Category: apache Httpclient

Apache HttpClient – Proxy Authentication ”; Previous Next In this chapter, we will learn how to create a HttpRequest authenticated using username and password and tunnel it through a proxy to a target host, using an example. Step 1 – Create a CredentialsProvider object The CredentialsProvider Interface maintains a collection to hold the user login credentials. You can create its object by instantiating the BasicCredentialsProvider class, the default implementation of this interface. CredentialsProvider credentialsPovider = new BasicCredentialsProvider(); Step 2 – Set the credentials You can set the required credentials to the CredentialsProvider object using the setCredentials() method. This method accepts two objects − AuthScope object − Authentication scope specifying the details like hostname, port number, and authentication scheme name. Credentials object − Specifying the credentials (username, password). Set the credentials using the setCredentials() method for both host and proxy as shown below. credsProvider.setCredentials(new AuthScope(“example.com”, 80), new UsernamePasswordCredentials(“user”, “mypass”)); credsProvider.setCredentials(new AuthScope(“localhost”, 8000), new UsernamePasswordCredentials(“abc”, “passwd”)); Step 3 – Create an HttpClientBuilder object Create a HttpClientBuilder using the custom() method of the HttpClients class as shown below − //Creating the HttpClientBuilder HttpClientBuilder clientbuilder = HttpClients.custom(); Step 4 – Set the CredentialsProvider You can set the CredentialsProvider object to a HttpClientBuilder object using the setDefaultCredentialsProvider() method. Pass the previously created CredentialsProvider object to this method. clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider); Step 5 – Build the CloseableHttpClient Build the CloseableHttpClient object using the build() method. CloseableHttpClient httpclient = clientbuilder.build(); Step 6 – Create the proxy and target hosts Create the target and proxy hosts by instantiating the HttpHost class. //Creating the target and proxy hosts HttpHost target = new HttpHost(“example.com”, 80, “http”); HttpHost proxy = new HttpHost(“localhost”, 8000, “http”); Step 7 – Set the proxy and build a RequestConfig object Create a RequestConfig.Builder object using the custom() method. Set the previously created proxyHost object to the RequestConfig.Builder using the setProxy() method. Finally, build the RequestConfig object using the build() method. RequestConfig.Builder reqconfigconbuilder= RequestConfig.custom(); reqconfigconbuilder = reqconfigconbuilder.setProxy(proxyHost); RequestConfig config = reqconfigconbuilder.build(); Step 8 – Create a HttpGet request object and set config object to it. Create a HttpGet object by instantiating the HttpGet class. Set the config object created in the previous step to this object using the setConfig() method. //Create the HttpGet request object HttpGet httpGet = new HttpGet(“/”); //Setting the config to the request httpget.setConfig(config); Step 9 – Execute the request Execute the request by passing the HttpHost object (target) and request (HttpGet) as parameters to the execute() method. HttpResponse httpResponse = httpclient.execute(targetHost, httpget); Example Following example demonstrates how to execute a HTTP request through a proxy using username and password. import org.apache.http.HttpHost; import org.apache.http.HttpResponse; import org.apache.http.auth.AuthScope; import org.apache.http.auth.UsernamePasswordCredentials; import org.apache.http.client.CredentialsProvider; import org.apache.http.client.config.RequestConfig; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.BasicCredentialsProvider; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClientBuilder; import org.apache.http.impl.client.HttpClients; public class ProxyAuthenticationExample { public static void main(String[] args) throws Exception { //Creating the CredentialsProvider object CredentialsProvider credsProvider = new BasicCredentialsProvider(); //Setting the credentials credsProvider.setCredentials(new AuthScope(“example.com”, 80), new UsernamePasswordCredentials(“user”, “mypass”)); credsProvider.setCredentials(new AuthScope(“localhost”, 8000), new UsernamePasswordCredentials(“abc”, “passwd”)); //Creating the HttpClientBuilder HttpClientBuilder clientbuilder = HttpClients.custom(); //Setting the credentials clientbuilder = clientbuilder.setDefaultCredentialsProvider(credsProvider); //Building the CloseableHttpClient object CloseableHttpClient httpclient = clientbuilder.build(); //Create the target and proxy hosts HttpHost targetHost = new HttpHost(“example.com”, 80, “http”); HttpHost proxyHost = new HttpHost(“localhost”, 8000, “http”); //Setting the proxy RequestConfig.Builder reqconfigconbuilder= RequestConfig.custom(); reqconfigconbuilder = reqconfigconbuilder.setProxy(proxyHost); RequestConfig config = reqconfigconbuilder.build(); //Create the HttpGet request object HttpGet httpget = new HttpGet(“/”); //Setting the config to the request httpget.setConfig(config); //Printing the status line HttpResponse response = httpclient.execute(targetHost, httpget); System.out.println(response.getStatusLine()); } } Output On executing, the above program generates the following output − HTTP/1.1 200 OK Print Page Previous Next Advertisements ”;

Apache HttpClient – Interceptors ”; Previous Next Interceptors are those which helps to obstruct or change requests or responses. Protocol interceptors in general act upon a specific header or a group of related headers. HttpClient library provides support for interceptors. Request interceptor The HttpRequestInterceptor interface represents the request interceptors. This interface contains a method known as a process in which you need to write the chunk of code to intercept the requests. On the client side, this method verifies/processes the requests before sending them to the server and, on the server side, this method is executed before evaluating the body of the request. Creating request interceptor You can create a request interceptor by following the steps given below. Step 1 – Create an object of HttpRequestInterceptor Create an object of the HttpRequestInterceptor interface by implementing its abstract method process. HttpRequestInterceptor requestInterceptor = new HttpRequestInterceptor() { @Override public void process(HttpRequest request, HttpContext context) throws HttpException, IOException { //Method implementation . . . . . }; Step 2 – Instantiate CloseableHttpClient object Build a custom CloseableHttpClient object by adding above created interceptor to it as shown below − //Creating a CloseableHttpClient object CloseableHttpClient httpclient = HttpClients.custom().addInterceptorFirst(requestInterceptor).build(); Using this object, you can carry out the request executions as usual. Example Following example demonstrates the usage of request interceptors. In this example, we have created a HTTP GET request object and added three headers: sample-header, demoheader, and test-header to it. In the processor() method of the interceptor, we are verifying the headers of the request sent; if any of those headers is sample-header, we are trying to remove it and display the list of headers of that particular request. import java.io.IOException; import org.apache.http.Header; import org.apache.http.HttpException; import org.apache.http.HttpRequest; import org.apache.http.HttpRequestInterceptor; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.message.BasicHeader; import org.apache.http.protocol.HttpContext; public class InterceptorsExample { public static void main(String args[]) throws Exception{ //Creating an HttpRequestInterceptor HttpRequestInterceptor requestInterceptor = new HttpRequestInterceptor() { @Override public void process(HttpRequest request, HttpContext context) throws HttpException, IOException { if(request.containsHeader(“sample-header”)) { System.out.println(“Contains header sample-header, removing it..”); request.removeHeaders(“sample-header”); } //Printing remaining list of headers Header[] headers= request.getAllHeaders(); for (int i = 0; i<headers.length;i++) { System.out.println(headers[i].getName()); } } }; //Creating a CloseableHttpClient object CloseableHttpClient httpclient = HttpClients.custom().addInterceptorFirst(requestInterceptor).build(); //Creating a request object HttpGet httpget1 = new HttpGet(“https://www.tutorialspoint.com/”); //Setting the header to it httpget1.setHeader(new BasicHeader(“sample-header”,”My first header”)); httpget1.setHeader(new BasicHeader(“demo-header”,”My second header”)); httpget1.setHeader(new BasicHeader(“test-header”,”My third header”)); //Executing the request HttpResponse httpresponse = httpclient.execute(httpget1); //Printing the status line System.out.println(httpresponse.getStatusLine()); } } Output On executing the above program, the following output is generated − Contains header sample-header, removing it.. demo-header test-header HTTP/1.1 200 OK Response interceptor The HttpResponseInterceptor interface represents the response interceptors. This interface contains a method known as process(). In this method, you need to write the chunk of code to intercept the responses. On the server side, this method verifies/processes the response before sending them to the client, and on the client side, this method is executed before evaluating the body of the response. Creating response interceptor You can create a response interceptor by following the steps given below − Step 1 – Create an object of HttpResponseInterceptor Create an object of the HttpResponseInterceptor interface by implementing its abstract method process. HttpResponseInterceptor responseInterceptor = new HttpResponseInterceptor() { @Override public void process(HttpResponse response, HttpContext context) throws HttpException, IOException { //Method implementation . . . . . . . . } }; Step 2: Instantiate CloseableHttpClient object Build a custom CloseableHttpClient object by adding above created interceptor to it, as shown below − //Creating a CloseableHttpClient object CloseableHttpClient httpclient = HttpClients.custom().addInterceptorFirst(responseInterceptor).build(); Using this object, you can carry out the request executions as usual. Example The following example demonstrates the usage of response interceptors. In this example, we have added three headers: sample-header, demo-header, and test-header to the response in the processor. After executing the request and obtaining the response, we printed names of all the headers of the response using the getAllHeaders() method. And in the output, you can observe the names of three headers in the list. import java.io.IOException; import org.apache.http.Header; import org.apache.http.HttpException; import org.apache.http.HttpResponse; import org.apache.http.HttpResponseInterceptor; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.protocol.HttpContext; public class ResponseInterceptorsExample { public static void main(String args[]) throws Exception{ //Creating an HttpRequestInterceptor HttpResponseInterceptor responseInterceptor = new HttpResponseInterceptor() { @Override public void process(HttpResponse response, HttpContext context) throws HttpException, IOException { System.out.println(“Adding header sample_header, demo-header, test_header to the response”); response.setHeader(“sample-header”, “My first header”); response.setHeader(“demo-header”, “My second header”); response.setHeader(“test-header”, “My third header”); } }; //Creating a CloseableHttpClient object CloseableHttpClient httpclient = HttpClients.custom().addInterceptorFirst(responseInterceptor).build(); //Creating a request object HttpGet httpget1 = new HttpGet(“https://www.tutorialspoint.com/”); //Executing the request HttpResponse httpresponse = httpclient.execute(httpget1); //Printing remaining list of headers Header[] headers = httpresponse.getAllHeaders(); for (int i = 0; i<headers.length;i++) { System.out.println(headers[i].getName()); } } } Output On executing, the above program generates the following result − On executing the above program generates the following output. Adding header sample_header, demo-header, test_header to the response Accept-Ranges Access-Control-Allow-Headers Access-Control-Allow-Origin Cache-Control Content-Type Date Expires Last-Modified Server Vary X-Cache sample-header demo-header test-header Print Page Previous Next Advertisements ”;

Apache HttpClient – Aborting a Request ”; Previous Next You can abort the current HTTP request using the abort() method, i.e., after invoking this method, on a particular request, execution of it will be aborted. If this method is invoked after one execution, responses of that execution will not be affected and the subsequent executions will be aborted. Example If you observe the following example, we have created a HttpGet request, printed the request format used using the getMethod(). Then, we have carried out another execution with the same request. Printed the status line using the 1st execution again. Finally, printed the status line of the second execution. As discussed, the responses of the 1st execution (execution before abort method) are printed (including the second status line that is written after the abort method) and, all the subsequent executions of the current request after the abort method are failed invoking an exception. import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; public class HttpGetExample { public static void main(String args[]) throws Exception{ //Creating an HttpClient object CloseableHttpClient httpclient = HttpClients.createDefault(); //Creating an HttpGet object HttpGet httpget = new HttpGet(“https://www.tutorialspoint.com/”); //Printing the method used System.out.println(httpget.getMethod()); //Executing the Get request HttpResponse httpresponse = httpclient.execute(httpget); //Printing the status line System.out.println(httpresponse.getStatusLine()); httpget.abort(); System.out.println(httpresponse.getEntity().getContentLength()); //Executing the Get request HttpResponse httpresponse2 = httpclient.execute(httpget); System.out.println(httpresponse2.getStatusLine()); } } Output On executing, the above program generates the following output − On executing, the above program generates the following output. GET HTTP/1.1 200 OK -1 Exception in thread “main” org.apache.http.impl.execchain.RequestAbortedException: Request aborted at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:180) at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185) at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89) at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110) at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185) at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83) at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:108) at HttpGetExample.main(HttpGetExample.java:32) Print Page Previous Next Advertisements ”;

Apache HttpClient – Response Handlers ”; Previous Next Processing the HTTP responses using the response handlers is recommended. In this chapter, we are going to discuss how to create response handlers and how to use them to process a response. If you use the response handler, all the HTTP connections will be released automatically. Creating a response handler The HttpClient API provides an interface known as ResponseHandler in the package org.apache.http.client. In order to create a response handler, implement this interface and override its handleResponse() method. Every response has a status code and if the status code is in between 200 and 300, that means the action was successfully received, understood, and accepted. Therefore, in our example, we will handle the entities of the responses with such status codes. Executing the request using response handler Follow the steps given below to execute the request using a response handler. Step 1 – Create an HttpClient Object The createDefault() method of the HttpClients class returns an object of the class CloseableHttpClient, which is the base implementation of the HttpClient interface. Using this method create an HttpClient object CloseableHttpClient httpclient = HttpClients.createDefault(); Step 2 – Instantiate the Response Handler Instantiate the response handler object created above using the following line of code − ResponseHandler<String> responseHandler = new MyResponseHandler(); Step 3 – Create a HttpGet Object The HttpGet class represents the HTTP GET request which retrieves the information of the given server using a URI. Create an HttpGet request by instantiating the HttpGet class and by passing a string representing the URI as a parameter to its constructor. ResponseHandler<String> responseHandler = new MyResponseHandler(); Step 4 – Execute the Get request using response handler The CloseableHttpClient class has a variant of execute() method which accepts two objects ResponseHandler and HttpUriRequest, and returns a response object. String httpResponse = httpclient.execute(httpget, responseHandler); Example Following example demonstrates the usage of response handlers. import java.io.IOException; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.ResponseHandler; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.util.EntityUtils; class MyResponseHandler implements ResponseHandler<String>{ public String handleResponse(final HttpResponse response) throws IOException{ //Get the status of the response int status = response.getStatusLine().getStatusCode(); if (status >= 200 && status < 300) { HttpEntity entity = response.getEntity(); if(entity == null) { return “”; } else { return EntityUtils.toString(entity); } } else { return “”+status; } } } public class ResponseHandlerExample { public static void main(String args[]) throws Exception{ //Create an HttpClient object CloseableHttpClient httpclient = HttpClients.createDefault(); //instantiate the response handler ResponseHandler<String> responseHandler = new MyResponseHandler(); //Create an HttpGet object HttpGet httpget = new HttpGet(“https://www.tutorialspoint.com/”); //Execute the Get request by passing the response handler object and HttpGet object String httpresponse = httpclient.execute(httpget, responseHandler); System.out.println(httpresponse); } } Output The above programs generate the following output − <!DOCTYPE html> <!–[if IE 8]><html class = “ie ie8”> <![endif]–> <!–[if IE 9]><html class = “ie ie9”> <![endif]–> <!–[if gt IE 9]><!–> <html lang = “en-US”> <!–<![endif]–> <head> <!– Basic –> <meta charset = “utf-8”> <meta http-equiv = “X-UA-Compatible” content = “IE = edge”> <meta name = “viewport” content = “width = device-width,initial-scale = 1.0,userscalable = yes”> <link href = “https://cdn.muicss.com/mui-0.9.39/extra/mui-rem.min.css” rel = “stylesheet” type = “text/css” /> <link rel = “stylesheet” href = “/questions/css/home.css?v = 3” /> <script src = “/questions/js/jquery.min.js”></script> <script src = “/questions/js/fontawesome.js”></script> <script src = “https://cdn.muicss.com/mui-0.9.39/js/mui.min.js”></script> </head> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <script> window.dataLayer = window.dataLayer || []; function gtag() {dataLayer.push(arguments);} gtag(”js”, new Date()); gtag(”config”, ”UA-232293-17”); </script> </body> Print Page Previous Next Advertisements ”;

Apache HttpClient – Overview ”; Previous Next The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. This is the foundation for data communication for the World Wide Web (i.e., Internet) since 1990. HTTP is a generic and stateless protocol which can be used for other purposes as well using extensions of its request methods, error codes, and headers. Basically, HTTP is a TCP/IP based communication protocol, that is used to deliver data (HTML files, image files, query results, etc.) on the World Wide Web. The default port is TCP 80, but other ports can be used as well. It provides a standardized way for computers to communicate with each other. HTTP specification defines how clients” request data will be constructed and sent to the server, and how the servers respond to these requests. What is Http Client Http client is a transfer library, it resides on the client side, sends and receives HTTP messages. It provides up to date, feature-rich and, efficient implementation which meets the recent HTTP standards. In addition to this using client library, one can build HTTP based applications such as web browsers, web service clients, etc. Features of Http Client Following are the prominent features of Http client − HttpClient library implements all the available HTTP methods. HttpClient library provides APIs to secure the requests using the Secure Socket Layer protocol. Using HttpClient, you can establish connections using proxies. You can authenticate connections using authentication schemes such as Basic, Digest, NTLMv1, NTLMv2, NTLM2 Session etc. HttpClient library supports sending requests through multiple threads. It manages multiple connections established from various threads using ClientConnectionPoolManager. Using Apache HttpClient library, you can set connection timeouts. Print Page Previous Next Advertisements ”;

Apache HttpClient – Http Post Request ”; Previous Next A POST request is used to send data to the server; for example, customer information, file upload, etc., using HTML forms. The HttpClient API provides a class named HttpPost which represents the POST request. Follow the steps given below to send a HTTP POST request using HttpClient library. Step 1 – Create an HttpClient Object The createDefault() method of the HttpClients class returns an object of the class CloseableHttpClient, which is the base implementation of the HttpClient interface. Using this method, create an HttpClient object. CloseableHttpClient httpClient = HttpClients.createDefault(); Step 2 – Create HttpPost Object The HttpPost class represents the HTTP POST request. This sends required data and retrieves the information of the given server using a URI. Create this request by instantiating the HttpPost class and pass a string value representing the URI, as a parameter to its constructor. HttpGet httpGet = new HttpGet(“https://www.tutorialspoint.com/”); Step 3 – Execute the Get Request The execute() method of the CloseableHttpClient object accepts a HttpUriRequest (interface) object (i.e. HttpGet, HttpPost, HttpPut, HttpHead etc.) and returns a response object. HttpResponse httpResponse = httpclient.execute(httpget); Example Following is an example which demonstrates the execution of the HTTP POST request using HttpClient library. import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; public class HttpPostExample { public static void main(String args[]) throws Exception{ //Creating a HttpClient object CloseableHttpClient httpclient = HttpClients.createDefault(); //Creating a HttpGet object HttpPost httppost = new HttpPost(“https://www.tutorialspoint.com/”); //Printing the method used System.out.println(“Request Type: “+httppost.getMethod()); //Executing the Get request HttpResponse httpresponse = httpclient.execute(httppost); Scanner sc = new Scanner(httpresponse.getEntity().getContent()); //Printing the status line System.out.println(httpresponse.getStatusLine()); while(sc.hasNext()) { System.out.println(sc.nextLine()); } } } Output The above program generates the following output. Request Type: POST <!DOCTYPE html> <!–[if IE 8]><html class = “ie ie8”> <![endif]–> <!–[if IE 9]><html class = “ie ie9”> <![endif]–> <!–[if gt IE 9]><!–> <html lang = “en-US”> <!–<![endif]–> <head> <!– Basic –> <meta charset = “utf-8”> <title>Parallax Scrolling, Java Cryptography, YAML, Python Data Science, Java i18n, GitLab, TestRail, VersionOne, DBUtils, Common CLI, Seaborn, Ansible, LOLCODE, Current Affairs 2018, Apache Commons Collections</title> <meta name = “Description” content = “Parallax Scrolling, Java Cryptography, YAML, Python Data Science, Java i18n, GitLab, TestRail, VersionOne, DBUtils, Common CLI, Seaborn, Ansible, LOLCODE, Current Affairs 2018, Intellij Idea, Apache Commons Collections, Java 9, GSON, TestLink, Inter Process Communication (IPC), Logo, PySpark, Google Tag Manager, Free IFSC Code, SAP Workflow”/> <meta name = “Keywords” content=”Python Data Science, Java i18n, GitLab, TestRail, VersionOne, DBUtils, Common CLI, Seaborn, Ansible, LOLCODE, Gson, TestLink, Inter Process Communication (IPC), Logo”/> <meta http-equiv = “X-UA-Compatible” content = “IE = edge”> <meta name = “viewport” conten t= “width = device-width,initial-scale = 1.0,userscalable = yes”> <link href = “https://cdn.muicss.com/mui-0.9.39/extra/mui-rem.min.css” rel = “stylesheet” type = “text/css” /> <link rel = “stylesheet” href = “/questions/css/home.css?v = 3” /> <script src = “/questions/js/jquery.min.js”></script> <script src = “/questions/js/fontawesome.js”></script> <script src = “https://cdn.muicss.com/mui-0.9.39/js/mui.min.js”></script> </head> . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . </script> </body> </html> Print Page Previous Next Advertisements ”;

Apache HttpClient Tutorial PDF Version Quick Guide Resources Job Search Discussion Http client is a transfer library. It resides on the client side, sends and receives Http messages. It provides up to date, feature-rich, and an efficient implementation which meets the recent Http standards. Audience This tutorial has been prepared for the beginners to help them understand the concepts of Apache HttpClient library. Prerequisites Before you start practicing various types of examples given in this reference, we assume that you already have knowledge in Java programming. And, having knowledge of Http protocol concepts helps in understanding this tutorial better. Print Page Previous Next Advertisements ”;

Apache HttpClient – Cookies Management ”; Previous Next Cookies are text files stored on the client computer and they are kept for various information tracking purpose. HttpClient provides support for cookies you can create and manage cookies. Creating a cookie Follow the steps given below to create a cookie using HttpClient library. Step 1 – Create Cookiestore object The CookieStore interface represents the abstract store for Cookie objects. You can create a cookie store by instantiating the BasicCookieStore class, a default implementation of this interface. //Creating the CookieStore object CookieStore cookieStore = new BasicCookieStore(); Step 2 – Create ClientCookie object In addition to the functionalities of a cookie, ClientCookie can get the original cookies in the server. You can create a client cookie by instantiating the BasicClientCookie class. To the constructor of this class, you need to pass the key-value pair that you desired to store in that particular cookie. //Creating client cookie BasicClientCookie clientCookie = new BasicClientCookie(“name”,”Raju”); Step 3 – Set values to the cookie To a client cookie, you can set/remove path, value, version, expiry date, domain, comment, and attribute using the respective methods. Calendar myCal = new GregorianCalendar(2018, 9, 26); Date expiryDate = myCal.getTime(); clientcookie.setExpiryDate(expiryDate); clientcookie.setPath(“/”); clientcookie.setSecure(true); clientcookie.setValue(“25”); clientcookie.setVersion(5); Step 4 – Add cookie to the cookie store You can add cookies to the cookie store using the addCookie() method of the BasicCookieStore class. Add the required cookies to the Cookiestore. //Adding the created cookies to cookie store cookiestore.addCookie(clientcookie); Example Following example demonstrates how to create cookies and add them to a cookie store. Here, we created a cookie store, a bunch of cookies by setting the domain and path values, and added these to the cookie store. import org.apache.http.client.CookieStore; import org.apache.http.impl.client.BasicCookieStore; import org.apache.http.impl.cookie.BasicClientCookie; public class CookieHandlingExample { public static void main(String args[]) throws Exception{ //Creating the CookieStore object CookieStore cookiestore = new BasicCookieStore(); //Creating client cookies BasicClientCookie clientcookie1 = new BasicClientCookie(“name”,”Raju”); BasicClientCookie clientcookie2 = new BasicClientCookie(“age”,”28″); BasicClientCookie clientcookie3 = new BasicClientCookie(“place”,”Hyderabad”); //Setting domains and paths to the created cookies clientcookie1.setDomain(“.sample.com”); clientcookie2.setDomain(“.sample.com”); clientcookie3.setDomain(“.sample.com”); clientcookie1.setPath(“/”); clientcookie2.setPath(“/”); clientcookie3.setPath(“/”); //Adding the created cookies to cookie store cookiestore.addCookie(clientcookie1); cookiestore.addCookie(clientcookie2); cookiestore.addCookie(clientcookie3); } } Retrieving a cookie You can get the cookies added to a cookie store using getCookies() method of the asicCookieStore class. This method returns a list which holds all the cookies in the cookie store. You can print the contents of a cookie store using the Iterator as shown below − //Retrieving the cookies List list = cookieStore.getCookies(); //Creating an iterator to the obtained list Iterator it = list.iterator(); while(it.hasNext()) { System.out.println(it.next()); } Example Following example demonstrates how to retrieve cookies from a cookie store. Here, we are adding a bunch of cookies to a cookie store and retrieving them back. import org.apache.http.client.CookieStore; import org.apache.http.impl.client.BasicCookieStore; import org.apache.http.impl.cookie.BasicClientCookie; public class CookieHandlingExample { public static void main(String args[]) throws Exception{ //Creating the CookieStore object CookieStore cookiestore = new BasicCookieStore(); //Creating client cookies BasicClientCookie clientcookie1 = new BasicClientCookie(“name”,”Raju”); BasicClientCookie clientcookie2 = new BasicClientCookie(“age”,”28″); BasicClientCookie clientcookie3 = new BasicClientCookie(“place”,”Hyderabad”); //Setting domains and paths to the created cookies clientcookie1.setDomain(“.sample.com”); clientcookie2.setDomain(“.sample.com”); clientcookie3.setDomain(“.sample.com”); clientcookie1.setPath(“/”); clientcookie2.setPath(“/”); clientcookie3.setPath(“/”); //Adding the created cookies to cookie store cookiestore.addCookie(clientcookie1); cookiestore.addCookie(clientcookie2); cookiestore.addCookie(clientcookie3); } } Output On executing, this program generates the following output − [version: 0][name: age][value: 28][domain: .sample.com][path: /][expiry: null] [version: 0][name: name][value: Raju][domain: my.example.com][path: /][expiry: null] [version: 0][name: place][value: Hyderabad][domain: .sample.com][path: /][expiry: null] Print Page Previous Next Advertisements ”;

Apache HttpClient – Form-Based Login ”; Previous Next Using the HttpClient library you can send a request or, login to a form by passing parameters. Follow the steps given below to login to a form. Step 1 – Create an HttpClient object The createDefault() method of the HttpClients class returns an object of the class CloseableHttpClient, which is the base implementation of the HttpClient interface. Using this method, create an HttpClient object − CloseableHttpClient httpClient = HttpClients.createDefault(); Step 2 – Create a RequestBuilder object The class RequestBuilder is used to build request by adding parameters to it. If the request type is PUT or POST, it adds the parameters to the request as URL encoded entity Create a RequestBuilder object (of type POST) using the post() method. //Building the post request object RequestBuilder reqbuilder = RequestBuilder.post(); Step 3 – Set Uri and parameters to the RequestBuilder. Set the URI and parameters to the RequestBuilder object using the setUri() and addParameter() methods of the RequestBuilder class. //Set URI and parameters RequestBuilder reqbuilder = reqbuilder.setUri(“http://httpbin.org/post”); reqbuilder = reqbuilder1.addParameter(“Name”, “username”).addParameter(“password”, “password”); Step 4 – Build the HttpUriRequest object After setting the required parameters, build the HttpUriRequest object using the build() method. //Building the HttpUriRequest object HttpUriRequest httppost = reqbuilder2.build(); Step 5 – Execute the request The execute method of the CloseableHttpClient object accepts a HttpUriRequest (interface) object (i.e. HttpGet, HttpPost, HttpPut, HttpHead etc.) and returns a response object. Execute the HttpUriRequest created in the previous steps by passing it to the execute() method. //Execute the request HttpResponse httpresponse = httpclient.execute(httppost); Example Following example demonstrates how to logon to a form by sending login credentials. Here, we have sent two parameters − username and password to a form and tried to print the message entity and status of the request. import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.client.methods.RequestBuilder; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import org.apache.http.util.EntityUtils; import java.io.IOException; import java.net.URISyntaxException; public class FormLoginExample { public static void main(String args[]) throws Exception { //Creating CloseableHttpClient object CloseableHttpClient httpclient = HttpClients.createDefault(); //Creating the RequestBuilder object RequestBuilder reqbuilder = RequestBuilder.post(); //Setting URI and parameters RequestBuilder reqbuilder1 = reqbuilder.setUri(“http://httpbin.org/post”); RequestBuilder reqbuilder2 = reqbuilder1.addParameter(“Name”, “username”).addParameter(“password”, “password”); //Building the HttpUriRequest object HttpUriRequest httppost = reqbuilder2.build(); //Executing the request HttpResponse httpresponse = httpclient.execute(httppost); //Printing the status and the contents of the response System.out.println(EntityUtils.toString(httpresponse.getEntity())); System.out.println(httpresponse.getStatusLine()); } } Output On executing, the above program generates the following output − { “args”: {}, “data”: “”, “files”: {}, “form”: { “Name”: “username”, “password”: “password” }, “headers”: { “Accept-Encoding”: “gzip,deflate”, “Connection”: “close”, “Content-Length”: “31”, “Content-Type”: “application/x-www-form-urlencoded; charset = UTF-8”, “Host”: “httpbin.org”, “User-Agent”: “Apache-HttpClient/4.5.6 (Java/1.8.0_91)” }, “json”: null, “origin”: “117.216.245.180”, “url”: “http://httpbin.org/post” } HTTP/1.1 200 OK Form Login with Cookies If your form stores cookies, instead of creating default CloseableHttpClient object. Create a CookieStore object by instantiating the BasicCookieStore class. //Creating a BasicCookieStore object BasicCookieStore cookieStore = new BasicCookieStore(); Create a HttpClientBuilder using the custom() method of the HttpClients class. //Creating an HttpClientBuilder object HttpClientBuilder clientbuilder = HttpClients.custom(); Set the cookie store to the client builder using the setDefaultCookieStore() method. //Setting default cookie store to the client builder object Clientbuilder = clientbuilder.setDefaultCookieStore(cookieStore); Build the CloseableHttpClient object using the build() method. //Building the CloseableHttpClient object CloseableHttpClient httpclient = clientbuilder1.build(); Build the HttpUriRequest object as specified above by passing execute the request. If the page stores cookies, the parameters you have passed will be added to the cookie store. You can print the contents of the CookieStore object where you can see your parameters (along with the previous ones the page stored in case). To print the cookies, get all the cookies from the CookieStore object using the getCookies() method. This method returns a List object. Using Iterator, print the list objects contents as shown below − //Printing the cookies List list = cookieStore.getCookies(); System.out.println(“list of cookies”); Iterator it = list.iterator(); if(it.hasNext()) { System.out.println(it.next()); } Print Page Previous Next Advertisements ”;

Apache HttpClient – Custom SSL Context ”; Previous Next Using Secure Socket Layer, you can establish a secured connection between the client and server. It helps to safeguard sensitive information such as credit card numbers, usernames, passwords, pins, etc. You can make connections more secure by creating your own SSL context using the HttpClient library. Follow the steps given below to customize SSLContext using HttpClient library − Step 1 – Create SSLContextBuilder object SSLContextBuilder is the builder for the SSLContext objects. Create its object using the custom() method of the SSLContexts class. //Creating SSLContextBuilder object SSLContextBuilder SSLBuilder = SSLContexts.custom(); Step 2 – Load the Keystore In the path Java_home_directory/jre/lib/security/, you can find a file named cacerts. Save this as your key store file (with extension .jks). Load the keystore file and, its password (which is changeit by default) using the loadTrustMaterial() method of the SSLContextBuilder class. //Loading the Keystore file File file = new File(“mykeystore.jks”); SSLBuilder = SSLBuilder.loadTrustMaterial(file, “changeit”.toCharArray()); Step 3 – build an SSLContext object An SSLContext object represents a secure socket protocol implementation. Build an SSLContext using the build() method. //Building the SSLContext SSLContext sslContext = SSLBuilder.build(); Step 4 – Creating SSLConnectionSocketFactory object SSLConnectionSocketFactory is a layered socket factory for TSL and SSL connections. Using this, you can verify the Https server using a list of trusted certificates and authenticate the given Https server. You can create this in many ways. Depending on the way you create an SSLConnectionSocketFactory object, you can allow all hosts, allow only self-signed certificates, allow only particular protocols, etc. To allow only particular protocols, create SSLConnectionSocketFactory object by passing an SSLContext object, string array representing the protocols need to be supported, string array representing the cipher suits need to be supported and a HostnameVerifier object to its constructor. new SSLConnectionSocketFactory(sslcontext, new String[]{“TLSv1”}, null, SSLConnectionSocketFactory.getDefaultHostnameVerifier()); To allow all hosts, create SSLConnectionSocketFactory object by passing a SSLContext object and a NoopHostnameVerifier object. //Creating SSLConnectionSocketFactory SSLConnectionSocketFactory object SSLConnectionSocketFactory sslConSocFactory = new SSLConnectionSocketFactory(sslcontext, new NoopHostnameVerifier()); Step 5 – Create an HttpClientBuilder object Create an HttpClientBuilder object using the custom() method of the HttpClients class. //Creating HttpClientBuilder HttpClientBuilder clientbuilder = HttpClients.custom(); Step 6 – Set the SSLConnectionSocketFactory object Set the SSLConnectionSocketFactory object to the HttpClientBuilder using the setSSLSocketFactory() method. //Setting the SSLConnectionSocketFactory clientbuilder = clientbuilder.setSSLSocketFactory(sslConSocFactory); Step 7 – Build the CloseableHttpClient object Build the CloseableHttpClient object by calling the build() method. //Building the CloseableHttpClient CloseableHttpClient httpclient = clientbuilder.build(); Step 8 – Create an HttpGet object The HttpGet class represents the HTTP GET request which retrieves the information of the given server using a URI. Create a HTTP GET request by instantiating the HttpGet class by passing a string representing the URI. //Creating the HttpGet request HttpGet httpget = new HttpGet(“https://example.com/”); Step 9 – Execute the request Execute the request using the execute() method. //Executing the request HttpResponse httpresponse = httpclient.execute(httpget); Example Following example demonstrates the customization of the SSLContrext − import java.io.File; import javax.net.ssl.SSLContext; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.conn.ssl.NoopHostnameVerifier; import org.apache.http.conn.ssl.SSLConnectionSocketFactory; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClientBuilder; import org.apache.http.impl.client.HttpClients; import org.apache.http.ssl.SSLContextBuilder; import org.apache.http.ssl.SSLContexts; import org.apache.http.util.EntityUtils; public class ClientCustomSSL { public final static void main(String[] args) throws Exception { //Creating SSLContextBuilder object SSLContextBuilder SSLBuilder = SSLContexts.custom(); //Loading the Keystore file File file = new File(“mykeystore.jks”); SSLBuilder = SSLBuilder.loadTrustMaterial(file, “changeit”.toCharArray()); //Building the SSLContext usiong the build() method SSLContext sslcontext = SSLBuilder.build(); //Creating SSLConnectionSocketFactory object SSLConnectionSocketFactory sslConSocFactory = new SSLConnectionSocketFactory(sslcontext, new NoopHostnameVerifier()); //Creating HttpClientBuilder HttpClientBuilder clientbuilder = HttpClients.custom(); //Setting the SSLConnectionSocketFactory clientbuilder = clientbuilder.setSSLSocketFactory(sslConSocFactory); //Building the CloseableHttpClient CloseableHttpClient httpclient = clientbuilder.build(); //Creating the HttpGet request HttpGet httpget = new HttpGet(“https://example.com/”); //Executing the request HttpResponse httpresponse = httpclient.execute(httpget); //printing the status line System.out.println(httpresponse.getStatusLine()); //Retrieving the HttpEntity and displaying the no.of bytes read HttpEntity entity = httpresponse.getEntity(); if (entity != null) { System.out.println(EntityUtils.toByteArray(entity).length); } } } Output On executing, the above program generates the following output. HTTP/1.1 200 OK 1270 Print Page Previous Next Advertisements ”;