Category: restful

RESTful Web Services – Resources ”; Previous Next What is a Resource? REST architecture treats every content as a resource. These resources can be Text Files, Html Pages, Images, Videos or Dynamic Business Data. REST Server simply provides access to resources and REST client accesses and modifies the resources. Here each resource is identified by URIs/ Global IDs. REST uses various representations to represent a resource where Text, JSON, XML. The most popular representations of resources are XML and JSON. Representation of Resources A resource in REST is a similar Object in Object Oriented Programming or is like an Entity in a Database. Once a resource is identified then its representation is to be decided using a standard format so that the server can send the resource in the above said format and client can understand the same format. For example, in RESTful Web Services – First Application chapter, a user is a resource which is represented using the following XML format − <user> <id>1</id> <name>Mahesh</name> <profession>Teacher</profession> </user> The same resource can be represented in JSON format as follows − { “id”:1, “name”:”Mahesh”, “profession”:”Teacher” } Good Resources Representation REST does not impose any restriction on the format of a resource representation. A client can ask for JSON representation whereas another client may ask for XML representation of the same resource to the server and so on. It is the responsibility of the REST server to pass the client the resource in the format that the client understands. Following are some important points to be considered while designing a representation format of a resource in RESTful Web Services. Understandability − Both the Server and the Client should be able to understand and utilize the representation format of the resource. Completeness − Format should be able to represent a resource completely. For example, a resource can contain another resource. Format should be able to represent simple as well as complex structures of resources. Linkablity − A resource can have a linkage to another resource, a format should be able to handle such situations. However, at present most of the web services are representing resources using either XML or JSON format. There are plenty of libraries and tools available to understand, parse, and modify XML and JSON data. Print Page Previous Next Advertisements ”;

RESTful Web Services – Environment Setup ”; Previous Next This tutorial will guide you on how to prepare a development environment to start your work with Jersey Framework to create RESTful Web Services. Jersey framework implements JAX-RS 2.0 API, which is a standard specification to create RESTful Web Services. This tutorial will also teach you how to setup JDK, Tomcat and Eclipse on your machine before you the Jersey Framework is setup. Setup Java Development Kit (JDK) You can download the latest version of SDK from Oracle”s Java site − Java SE Downloads. You will find the instructions for installing JDK in the downloaded files. Follow the given instructions to install and configure the setup. Finally set the PATH and JAVA_HOME environment variables to refer to the directory that contains Java and Javac, typically java_install_dir/bin and java_install_dir respectively. If you are running Windows and installed the JDK in C:jdk1.7.0_75, you would have to put the following line in your C:autoexec.bat file. set PATH = C:jdk1.7.0_75bin;%PATH% set JAVA_HOME = C:jdk1.7.0_75 Alternatively, on Windows NT/2000/XP, you could also right-click on My Computer → select Properties → then Advanced → then Environment Variables. Then, you would update the PATH value and press the OK button. On Unix (Solaris, Linux, etc.), if the SDK is installed in /usr/local/jdk1.7.0_75 and you use the C Shell, you would put the following into your .cshrc file. setenv PATH /usr/local/jdk1.7.0_75/bin:$PATH setenv JAVA_HOME /usr/local/jdk1.7.0_75 Alternatively, if you use an Integrated Development Environment (IDE) like Borland JBuilder, Eclipse, IntelliJ IDEA, or Sun ONE Studio, compile and run a simple program to confirm that the IDE knows where you installed Java, otherwise do proper setup as given document of the IDE. Setup Eclipse IDE All the examples in this tutorial have been written using the Eclipse IDE. So, I would suggest you should have the latest version of Eclipse installed on your machine. To install Eclipse IDE, download the latest Eclipse binaries from https://www.eclipse.org/downloads/. Once you downloaded the installation, unpack the binary distribution to a convenient location. For example, in C:eclipse on windows, or /usr/local/eclipse on Linux/Unix and finally set the PATH variable appropriately. Eclipse can be started by executing the following commands on a windows machine, or you can simply double click on eclipse.exe. %C:eclipseeclipse.exe Eclipse can be started by executing the following commands on Unix (Solaris, Linux, etc.) machine − $/usr/local/eclipse/eclipse After a successful startup, if everything is fine, then your screen should display the following result − Setup Jersey Framework Libraries Now, if everything is fine, then you can proceed to setup the Jersey framework. Following are a few simple steps to download and install the framework on your machine. Make a choice whether you want to install Jersey on Windows, or Unix and then proceed to the next step to download the .zip file for windows and then the .tz file for Unix. Download the latest version of Jersey framework binaries from the following link – https://jersey.java.net/download.html. At the time of writing this tutorial, I downloaded jaxrs-ri-2.17.zip on my Windows machine and when you unzip the downloaded file it will give you the directory structure inside E:jaxrs-ri-2.17jaxrs-ri as shown in the following screenshot. You will find all the Jersey libraries in the directories C:jaxrs-ri-2.17jaxrs-rilib and dependencies in C:jaxrs-ri-2.17jaxrs-riext. Make sure you set your CLASSPATH variable on this directory properly otherwise you will face problem while running your application. If you are using Eclipse, then it is not required to set the CLASSPATH because all the settings will be done through Eclipse. Setup Apache Tomcat You can download the latest version of Tomcat from https://tomcat.apache.org/. Once you downloaded the installation, unpack the binary distribution into a convenient location. For example in C:apache-tomcat-7.0.59 on windows, or /usr/local/apache-tomcat-7.0.59 on Linux/Unix and set CATALINA_HOME environment variable pointing to the installation locations. Tomcat can be started by executing the following commands on a windows machine, or you can simply double click on startup.bat. %CATALINA_HOME%binstartup.bat or C:apache-tomcat-7.0.59binstartup.bat Tomcat can be started by executing the following commands on a Unix (Solaris, Linux, etc.) machine − $CATALINA_HOME/bin/startup.sh or /usr/local/apache-tomcat-7.0.59/bin/startup.sh After a successful startup, the default web applications included with Tomcat will be available by visiting http://localhost:8080/. If everything is fine then it should display the following result − Further information about configuring and running Tomcat can be found in the documentation included on this page. This information can also be found on the Tomcat website − https://tomcat.apache.org. Tomcat can be stopped by executing the following commands on a windows machine − %CATALINA_HOME%binshutdown or C:apache-tomcat-7.0.59binshutdown Tomcat can be stopped by executing the following commands on Unix (Solaris, Linux, etc.) machine − $CATALINA_HOME/bin/shutdown.sh or /usr/local/apache-tomcat-7.0.59/bin/shutdown.sh Once you are done with this last step, you are ready to proceed for your first Jersey example which you will see in the next chapter. Print Page Previous Next Advertisements ”;