Category: mapstruct

MapStruct – Quick Guide ”; Previous Next MapStruct – Overview MapStruct is an annotation processor which is plugged into Java Compiler. Once plugged in, it can be used by command line tools like maven, gradle to process the mapping annotation to create a mapper class at compile time. When Mapping is required? In multilayered applications, data objects are used to fetch data from database and UI interacts with Models. Now data fetched into data models is required to map to Model or java beans to be passed to UI.Consider the following case. Entity class connected with database. StudentEntity.java @Entity class StudentEntity { String id; String name; } Model class connected with UI. Student.java class Student { String id; String name; } How MapStruct Works? MapStruct automates the process of creating a mapper to map data objects with model objects using annotations. It creates a mapper implementation at compile time which helps developer to figure out error during development and make is easy to understand. For example − StudentMapper.java @Mapper class StudentMapper { StudentMapper INSTANCE = Mappers.getMapper( StudentMapper.class ); StudentEntity modelToEntity(Student student); } Now StudentMapper.INSTANCE can be used to get mapped objects easily. StudentEntity studentEntity = StudentMapper.INSTANCE.modelToEntity(student); MapStruct – Environment Setup MapStruct is a Java based library, so the very first requirement is to have JDK installed on your machine. Step 1 – Setup Java Development Kit (JDK) You can download the latest version of SDK from Oracle”s Java site − Java SE Downloads. You will find instructions for installing JDK in downloaded files, follow the given instructions to install and configure the setup. Finally set 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 have installed the JDK in C:jdk-9.0.1, you would have to put the following line in your C:autoexec.bat file. set PATH=C:jdk-11.0.11bin;%PATH% set JAVA_HOME=C:jdk-11.0.11 Alternatively, on Windows NT/2000/XP, you will have to right-click on My Computer, select Properties → Advanced → Environment Variables. Then, you will have to update the PATH value and click the OK button. On Unix (Solaris, Linux, etc.), if the SDK is installed in /usr/local/jdk-9.0.1 and you use the C shell, you will have to put the following into your .cshrc file. setenv PATH /usr/local/jdk-11.0.11/bin:$PATH setenv JAVA_HOME /usr/local/jdk-11.0.11 Alternatively, if you use an Integrated Development Environment (IDE) like Borland JBuilder, Eclipse, IntelliJ IDEA, or Sun ONE Studio, you will have to compile and run a simple program to confirm that the IDE knows where you have installed Java. Otherwise, you will have to carry out a proper setup as given in the document of the IDE. Step 2 – Install mapstruct library along with dependencies Download following jars from MVNRepository and use them in your classpath. mapstruct-1.5.0.Beta1.jar mapstruct-processor-1.5.0.Beta1.jar Make sure you set your CLASSPATH variable on this directory properly otherwise you will face a problem while running your application. Step 3 – Setup Eclipse IDE All the examples in this tutorial have been written using Eclipse IDE. So we would suggest you should have the latest version of Eclipse installed on your machine. To install Eclipse IDE, download the latest Eclipse binaries from www.eclipse.org/downloads. Once you download the installation, unpack the binary distribution into a convenient location. For example, in C:eclipse on Windows, or /usr/local/eclipse on Linux/Unix and finally set PATH variable appropriately. Eclipse can be started by executing the following commands on 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 it should display the following result − Step 4 – Create a Maven Project C:MVN>mvn archetype:generate -DgroupId = com.tutorialspoint.mapping -DartifactId = mapping -DarchetypeArtifactId = maven-archetype-quickstart -DinteractiveMode = false It will create a maven project. Now update the pom.xml file as follows − <project xmlns=”http://maven.apache.org/POM/4.0.0″ xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=”http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd”> <modelVersion>4.0.0</modelVersion> <groupId>com.tutorialspoint.mapping</groupId> <artifactId>mapping</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> <name>mapping</name> <url>http://maven.apache.org</url> <dependencies> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter-engine</artifactId> <version>5.0.0</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct</artifactId> <version>1.5.0.Beta1</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.1</version> <configuration> <source>11</source> <target>11</target> <annotationProcessorPaths> <path> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>1.5.0.Beta1</version> </path> </annotationProcessorPaths> </configuration> </plugin> </plugins> </build> </project> Run the following command to update maven dependencies and build project. mvn package Once command is successful. Import the maven based project in Eclipse as a maven project. Rest Eclipse will handle. MapStruct – Basic Mapping Using mapstruct is very easy. To create a mapper use org.mapstruct.Mapper annotation on an interface. @Mapper public interface StudentMapper {…} Now create a conversion method in interface. @Mapper public interface StudentMapper { Student getModelFromEntity(StudentEntity student); } In case both source and target object properties have same name, those properties will be mapped automatically. In case property name is different, use the @Mapping annotation as following − @Mapper public interface StudentMapper { @Mapping(target=”className”, source=”classVal”) Student getModelFromEntity(StudentEntity student); } Here className is the property name in Student, a target object and classVal is the property name in StudentEntity, a source object. Example Open project mapping as created in Environment Setup chapter in Eclipse. Create Student.java with following code − Student.java package com.tutorialspoint.model; public class Student { private int id; private String name; private String className; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getClassName() { return className; } public void setClassName(String className) { this.className = className;

MapStruct – Mapping Map ”; Previous Next Using Mapstruct we can create mapping of map objects using @MapMapping annotation. Other rules of mapping are same as we”ve seen so far. Syntax @Mapper public interface UtilityMapper { @MapMapping(valueDateFormat = “dd.MM.yyyy”) Map<String, String> getMap(Map<Long, GregorianCalendar> source); } Following example demonstrates the same. Example Open project mapping as updated in Mapping List chapter in Eclipse. Create UtilityMapper.java with following code − UtilityMapper.java package com.tutorialspoint.mapper; import java.util.GregorianCalendar; import java.util.Map; import org.mapstruct.MapMapping; import org.mapstruct.Mapper; @Mapper public interface UtilityMapper { @MapMapping(valueDateFormat = “dd.MM.yyyy”) Map<String, String> getMap(Map<Long, GregorianCalendar> source); } Create UtilityMapperTest.java with following code − UtilityMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import java.util.GregorianCalendar; import java.util.HashMap; import java.util.Map; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.mapper.UtilityMapper; public class UtilityMapperTest { private UtilityMapper utilityMapper = Mappers.getMapper(UtilityMapper.class); @Test public void testMapMapping() { Map<Long, GregorianCalendar> source = new HashMap<>(); source.put(1L, new GregorianCalendar(2015, 3, 5)); Map<String, String> target = utilityMapper.getMap(source); assertEquals(“05.04.2015”, target.get(“1″)); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.CarMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.327 sec Running com.tutorialspoint.mapping.DeliveryAddressMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Running com.tutorialspoint.mapping.UtilityMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Results : Tests run: 5, Failures: 0, Errors: 0, Skipped: 0 … Print Page Previous Next Advertisements ”;

MapStruct – Environment Setup ”; Previous Next MapStruct is a Java based library, so the very first requirement is to have JDK installed on your machine. Step 1 – Setup Java Development Kit (JDK) You can download the latest version of SDK from Oracle”s Java site − Java SE Downloads. You will find instructions for installing JDK in downloaded files, follow the given instructions to install and configure the setup. Finally set 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 have installed the JDK in C:jdk-9.0.1, you would have to put the following line in your C:autoexec.bat file. set PATH=C:jdk-11.0.11bin;%PATH% set JAVA_HOME=C:jdk-11.0.11 Alternatively, on Windows NT/2000/XP, you will have to right-click on My Computer, select Properties → Advanced → Environment Variables. Then, you will have to update the PATH value and click the OK button. On Unix (Solaris, Linux, etc.), if the SDK is installed in /usr/local/jdk-9.0.1 and you use the C shell, you will have to put the following into your .cshrc file. setenv PATH /usr/local/jdk-11.0.11/bin:$PATH setenv JAVA_HOME /usr/local/jdk-11.0.11 Alternatively, if you use an Integrated Development Environment (IDE) like Borland JBuilder, Eclipse, IntelliJ IDEA, or Sun ONE Studio, you will have to compile and run a simple program to confirm that the IDE knows where you have installed Java. Otherwise, you will have to carry out a proper setup as given in the document of the IDE. Step 2 – Install mapstruct library along with dependencies Download following jars from MVNRepository and use them in your classpath. mapstruct-1.5.0.Beta1.jar mapstruct-processor-1.5.0.Beta1.jar Make sure you set your CLASSPATH variable on this directory properly otherwise you will face a problem while running your application. Step 3 – Setup Eclipse IDE All the examples in this tutorial have been written using Eclipse IDE. So we would suggest you should have the latest version of Eclipse installed on your machine. To install Eclipse IDE, download the latest Eclipse binaries from www.eclipse.org/downloads. Once you download the installation, unpack the binary distribution into a convenient location. For example, in C:eclipse on Windows, or /usr/local/eclipse on Linux/Unix and finally set PATH variable appropriately. Eclipse can be started by executing the following commands on 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 it should display the following result − Step 4 – Create a Maven Project C:MVN>mvn archetype:generate -DgroupId = com.tutorialspoint.mapping -DartifactId = mapping -DarchetypeArtifactId = maven-archetype-quickstart -DinteractiveMode = false It will create a maven project. Now update the pom.xml file as follows − <project xmlns=”http://maven.apache.org/POM/4.0.0″ xmlns:xsi=”http://www.w3.org/2001/XMLSchema-instance” xsi:schemaLocation=”http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd”> <modelVersion>4.0.0</modelVersion> <groupId>com.tutorialspoint.mapping</groupId> <artifactId>mapping</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> <name>mapping</name> <url>http://maven.apache.org</url> <dependencies> <dependency> <groupId>org.junit.jupiter</groupId> <artifactId>junit-jupiter-engine</artifactId> <version>5.0.0</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct</artifactId> <version>1.5.0.Beta1</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.1</version> <configuration> <source>11</source> <target>11</target> <annotationProcessorPaths> <path> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>1.5.0.Beta1</version> </path> </annotationProcessorPaths> </configuration> </plugin> </plugins> </build> </project> Run the following command to update maven dependencies and build project. mvn package Once command is successful. Import the maven based project in Eclipse as a maven project. Rest Eclipse will handle. Print Page Previous Next Advertisements ”;

MapStruct – Custom Mapping ”; Previous Next We can add custom methods as well to the Mapper created using org.mapstruct.Mapper annotation. We can create abstract class as well intead of an Interface. Mapstruct automatically creates the corresponding mapper class. Now create a default conversion method in interface. @Mapper public interface StudentMapper { default Student getModelFromEntity(StudentEntity studentEntity){ Student student = new Student(); student.setId(studentEntity.getId()); student.setName(studentEntity.getName()); student.setClassName(studentEntity.getClassVal()); return student; } } In similar fashion, we can create an abstract class as well as a mapper. @Mapper public absgract class StudentMapper { Student getModelFromEntity(StudentEntity studentEntity){ Student student = new Student(); student.setId(studentEntity.getId()); student.setName(studentEntity.getName()); student.setClassName(studentEntity.getClassVal()); return student; } } Example Open project mapping as updated in Basic Mapping chapter in Eclipse. Student.java package com.tutorialspoint.model; public class Student { private int id; private String name; private String className; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getClassName() { return className; } public void setClassName(String className) { this.className = className; } } StudentEntity.java package com.tutorialspoint.entity; public class StudentEntity { private int id; private String name; private String classVal; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getClassVal() { return classVal; } public void setClassVal(String classVal) { this.classVal = classVal; } } StudentMapper.java package com.tutorialspoint.mapper; import org.mapstruct.Mapper; import org.mapstruct.Mapping; import com.tutorialspoint.entity.StudentEntity; import com.tutorialspoint.model.Student; @Mapper public interface StudentMapper { default Student getModelFromEntity(StudentEntity studentEntity){ Student student = new Student(); student.setId(studentEntity.getId()); student.setName(studentEntity.getName()); student.setClassName(studentEntity.getClassVal()); return student; } @Mapping(target=”classVal”, source=”className”) StudentEntity getEntityFromModel(Student student); } StudentMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.entity.StudentEntity; import com.tutorialspoint.mapper.StudentMapper; import com.tutorialspoint.model.Student; public class StudentMapperTest { private StudentMapper studentMapper = Mappers.getMapper(StudentMapper.class); @Test public void testEntityToModel() { StudentEntity entity = new StudentEntity(); entity.setClassVal(“X”); entity.setName(“John”); entity.setId(1); Student model = studentMapper.getModelFromEntity(entity); assertEquals(entity.getClassVal(), model.getClassName()); assertEquals(entity.getName(), model.getName()); assertEquals(entity.getId(), model.getId()); } @Test public void testModelToEntity() { Student model = new Student(); model.setId(1); model.setName(“John”); model.setClassName(“X”); StudentEntity entity = studentMapper.getEntityFromModel(model); assertEquals(entity.getClassVal(), model.getClassName()); assertEquals(entity.getName(), model.getName()); assertEquals(entity.getId(), model.getId()); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.004 sec … Print Page Previous Next Advertisements ”;

MapStruct – Basic Mapping ”; Previous Next Using mapstruct is very easy. To create a mapper use org.mapstruct.Msapper annotation on an interface. @Mapper public interface StudentMapper {…} Now create a conversion method in interface. @Mapper public interface StudentMapper { Student getModelFromEntity(StudentEntity student); } In case both source and target object properties have same name, those properties will be mapped automatically. In case property name is different, use the @Mapping annotation as following − @Mapper public interface StudentMapper { @Mapping(target=”className”, source=”classVal”) Student getModelFromEntity(StudentEntity student); } Here className is the property name in Student, a target object and classVal is the property name in StudentEntity, a source object. Example Open project mapping as created in Environment Setup chapter in Eclipse. Create Student.java with following code − Student.java package com.tutorialspoint.model; public class Student { private int id; private String name; private String className; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getClassName() { return className; } public void setClassName(String className) { this.className = className; } } Create Student.java with following code − StudentEntity.java package com.tutorialspoint.entity; public class StudentEntity { private int id; private String name; private String classVal; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getClassVal() { return classVal; } public void setClassVal(String classVal) { this.classVal = classVal; } } Create StudentMapper.java with following code − StudentMapper.java package com.tutorialspoint.mapper; import org.mapstruct.Mapper; import org.mapstruct.Mapping; import com.tutorialspoint.entity.StudentEntity; import com.tutorialspoint.model.Student; @Mapper public interface StudentMapper { @Mapping(target=”className”, source=”classVal”) Student getModelFromEntity(StudentEntity student); @Mapping(target=”classVal”, source=”className”) StudentEntity getEntityFromModel(Student student); } Create StudentMapperTest.java with following code − StudentMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.entity.StudentEntity; import com.tutorialspoint.mapper.StudentMapper; import com.tutorialspoint.model.Student; public class StudentMapperTest { private StudentMapper studentMapper = Mappers.getMapper(StudentMapper.class); @Test public void testEntityToModel() { StudentEntity entity = new StudentEntity(); entity.setClassVal(“X”); entity.setName(“John”); entity.setId(1); Student model = studentMapper.getModelFromEntity(entity); assertEquals(entity.getClassVal(), model.getClassName()); assertEquals(entity.getName(), model.getName()); assertEquals(entity.getId(), model.getId()); } @Test public void testModelToEntity() { Student model = new Student(); model.setId(1); model.setName(“John”); model.setClassName(“X”); StudentEntity entity = studentMapper.getEntityFromModel(model); assertEquals(entity.getClassVal(), model.getClassName()); assertEquals(entity.getName(), model.getName()); assertEquals(entity.getId(), model.getId()); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.004 sec … Print Page Previous Next Advertisements ”;

MapStruct – Mapping Multiple Objects ”; Previous Next We can add map multiple objects as well. For Example, we want to get a DeliveryAddress Object using Student and Address object. Now create a mapper interface which can map two objects into one. @Mapper public interface DeliveryAddressMapper { @Mapping(source = “student.name”, target = “name”) @Mapping(source = “address.houseNo”, target = “houseNumber”) DeliveryAddress getDeliveryAddress(StudentEntity student, AddressEntity address); } Example Open project mapping as updated in Custom Mapping chapter in Eclipse. Create DeliveryAddress.java with following code − DeliveryAddress.java package com.tutorialspoint.model; public class DeliveryAddress { private String name; private int houseNumber; private String city; private String state; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getHouseNumber() { return houseNumber; } public void setHouseNumber(int houseNumber) { this.houseNumber = houseNumber; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } } Create AddressEntity.java with following code − AddressEntity.java package com.tutorialspoint.entity; public class AddressEntity { private int houseNo; private String city; private String state; public int getHouseNo() { return houseNo; } public void setHouseNo(int houseNo) { this.houseNo = houseNo; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } } Create DeliveryAddressMapper.java with following code − DeliveryAddressMapper.java package com.tutorialspoint.mapper; import org.mapstruct.Mapper; import org.mapstruct.Mapping; import com.tutorialspoint.entity.AddressEntity; import com.tutorialspoint.entity.StudentEntity; import com.tutorialspoint.model.DeliveryAddress; @Mapper public interface DeliveryAddressMapper { @Mapping(source = “student.name”, target = “name”) @Mapping(source = “address.houseNo”, target = “houseNumber”) DeliveryAddress getDeliveryAddress(StudentEntity student, AddressEntity address); } Create DeliveryAddressMapperTest.java with following code − DeliveryAddressMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.entity.AddressEntity; import com.tutorialspoint.entity.StudentEntity; import com.tutorialspoint.mapper.DeliveryAddressMapper; import com.tutorialspoint.model.DeliveryAddress; public class DeliveryAddressMapperTest { private DeliveryAddressMapper deliveryAddressMapper = Mappers.getMapper(DeliveryAddressMapper.class); @Test public void testEntityToModel() { StudentEntity student = new StudentEntity(); student.setClassVal(“X”); student.setName(“John”); student.setId(1); AddressEntity address = new AddressEntity(); address.setCity(“Y”); address.setState(“Z”); address.setHouseNo(1); DeliveryAddress deliveryAddress = deliveryAddressMapper.getDeliveryAddress(student, address); assertEquals(deliveryAddress.getName(), student.getName()); assertEquals(deliveryAddress.getCity(), address.getCity()); assertEquals(deliveryAddress.getState(), address.getState()); assertEquals(deliveryAddress.getHouseNumber(), address.getHouseNo()); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.DeliveryAddressMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.011 sec Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Results : Tests run: 3, Failures: 0, Errors: 0, Skipped: 0 … Print Page Previous Next Advertisements ”;

MapStruct – Useful Resources ”; Previous Next The following resources contain additional information on MapStruct. Please use them to get more in-depth knowledge on this. Useful Links on MapStruct MapStruct − Official site of MapStruct Useful Books on MapStruct To enlist your site on this page, please drop an email to [email protected] Print Page Previous Next Advertisements ”;

MapStruct – Using defaultExpression ”; Previous Next Using Mapstruct we can pass a computed value using defaultExpression in case source property is null using defaultExpression attribute of @Mapping annotation. Syntax @Mapping(target = “target-property”, source=”source-property” defaultExpression = “default-value-method”) Here default-value-method − target-property will be set as result of default-value-method in case source-property is null. Following example demonstrates the same. Example Open project mapping as updated in Mapping Using defaultValue chapter in Eclipse. Update CarEntity.java with following code − CarEntity.java package com.tutorialspoint.entity; import java.util.GregorianCalendar; public class CarEntity { private int id; private double price; private GregorianCalendar manufacturingDate; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } public GregorianCalendar getManufacturingDate() { return manufacturingDate; } public void setManufacturingDate(GregorianCalendar manufacturingDate) { this.manufacturingDate = manufacturingDate; } public String getName() { return name; } public void setName(String name) { this.name = name; } } Update Car.java with following code − Car.java package com.tutorialspoint.model; public class Car { private int id; private String price; private String manufacturingDate; private String brand; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getPrice() { return price; } public void setPrice(String price) { this.price = price; } public String getManufacturingDate() { return manufacturingDate; } public void setManufacturingDate(String manufacturingDate) { this.manufacturingDate = manufacturingDate; } public String getBrand() { return brand; } public void setBrand(String brand) { this.brand = brand; } public String getName() { return name; } public void setName(String name) { this.name = name; } } Update CarMapper.java with following code − CarMapper.java package com.tutorialspoint.mapper; import org.mapstruct.Mapper; import org.mapstruct.Mapping; import com.tutorialspoint.entity.CarEntity; import com.tutorialspoint.model.Car; import java.util.UUID; @Mapper( imports = UUID.class ) public interface CarMapper { @Mapping(source = “name”, target = “name”, defaultExpression = “java(UUID.randomUUID().toString())”) @Mapping(target = “brand”, constant = “BMW”) @Mapping(source = “price”, target = “price”, numberFormat = “$#.00”) @Mapping(source = “manufacturingDate”, target = “manufacturingDate”, dateFormat = “dd.MM.yyyy”) Car getModelFromEntity(CarEntity carEntity); } Update CarMapperTest.java with following code − CarMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import static org.junit.jupiter.api.Assertions.assertNotNull; import java.util.GregorianCalendar; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.entity.CarEntity; import com.tutorialspoint.mapper.CarMapper; import com.tutorialspoint.model.Car; public class CarMapperTest { private CarMapper carMapper=Mappers.getMapper(CarMapper.class); @Test public void testEntityToModel() { CarEntity entity = new CarEntity(); entity.setPrice(345000); entity.setId(1); entity.setManufacturingDate(new GregorianCalendar(2015, 3, 5)); Car model = carMapper.getModelFromEntity(entity); assertEquals(model.getPrice(), “$345000.00”); assertEquals(entity.getId(), model.getId()); assertEquals(“05.04.2015”, model.getManufacturingDate()); assertNotNull(model.getName()); assertEquals(“BMW”, model.getBrand()); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.CarMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.035 sec Running com.tutorialspoint.mapping.DeliveryAddressMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Results : Tests run: 4, Failures: 0, Errors: 0, Skipped: 0 … Print Page Previous Next Advertisements ”;

MapStruct – Using dateFormat ”; Previous Next MapStruct handles conversion of date to String in required format seamlessly. We can pass the required format as dateFormat during @Mapping annotation. For example, consider a case where a date stored in numbers is to be shown in particular format. Source − Entity has date as GregorianCalendar(2015, 3, 5). Target − Model to show date as 05.04.2015. dateFormat − Use format dd.MM.yyyy Example Open project mapping as updated in Mapping Using numberFormat chapter in Eclipse. Update CarEntity.java with following code − CarEntity.java package com.tutorialspoint.entity; import java.util.GregorianCalendar; public class CarEntity { private int id; private double price; private GregorianCalendar manufacturingDate; public int getId() { return id; } public void setId(int id) { this.id = id; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } public GregorianCalendar getManufacturingDate() { return manufacturingDate; } public void setManufacturingDate(GregorianCalendar manufacturingDate) { this.manufacturingDate = manufacturingDate; } } Update Car.java with following code − Car.java package com.tutorialspoint.model; public class Car { private int id; private String price; private String manufacturingDate; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getPrice() { return price; } public void setPrice(String price) { this.price = price; } public String getManufacturingDate() { return manufacturingDate; } public void setManufacturingDate(String manufacturingDate) { this.manufacturingDate = manufacturingDate; } } Update CarMapper.java with following code − CarMapper.java package com.tutorialspoint.mapper; import org.mapstruct.Mapper; import org.mapstruct.Mapping; import com.tutorialspoint.entity.CarEntity; import com.tutorialspoint.model.Car; @Mapper public interface CarMapper { @Mapping(source = “price”, target = “price”, numberFormat = “$#.00”) @Mapping(source = “manufacturingDate”, target = “manufacturingDate”, dateFormat = “dd.MM.yyyy”) Car getModelFromEntity(CarEntity carEntity); } Update CarMapperTest.java with following code − CarMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import java.util.GregorianCalendar; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.entity.CarEntity; import com.tutorialspoint.mapper.CarMapper; import com.tutorialspoint.model.Car; public class CarMapperTest { private CarMapper carMapper = Mappers.getMapper(CarMapper.class); @Test public void testEntityToModel() { CarEntity entity = new CarEntity(); entity.setPrice(345000); entity.setId(1); entity.setManufacturingDate(new GregorianCalendar(2015, 3, 5)); Car model = carMapper.getModelFromEntity(entity); assertEquals(model.getPrice(), “$345000.00”); assertEquals(entity.getId(), model.getId()); assertEquals(“05.04.2015″, model.getManufacturingDate()); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.CarMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.035 sec Running com.tutorialspoint.mapping.DeliveryAddressMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Results : Tests run: 4, Failures: 0, Errors: 0, Skipped: 0 … Print Page Previous Next Advertisements ”;

MapStruct – Mapping List ”; Previous Next Using Mapstruct we can map list in similar fashion as we map primitives. To get a list of objects, we should provide a mapper method which can map an object. Syntax @Mapper public interface CarMapper { List<String> getListOfStrings(List<Integer> listOfIntegers); List<Car> getCars(List<CarEntity> carEntities); Car getModelFromEntity(CarEntity carEntity); } Following example demonstrates the same. Example Open project mapping as updated in Mapping Using defaultExpression chapter in Eclipse. Update CarEntity.java with following code − CarEntity.java package com.tutorialspoint.entity; import java.util.GregorianCalendar; public class CarEntity { private int id; private double price; private GregorianCalendar manufacturingDate; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public double getPrice() { return price; } public void setPrice(double price) { this.price = price; } public GregorianCalendar getManufacturingDate() { return manufacturingDate; } public void setManufacturingDate(GregorianCalendar manufacturingDate) { this.manufacturingDate = manufacturingDate; } public String getName() { return name; } public void setName(String name) { this.name = name; } } Update Car.java with following code − Car.java package com.tutorialspoint.model; public class Car { private int id; private String price; private String manufacturingDate; private String brand; private String name; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getPrice() { return price; } public void setPrice(String price) { this.price = price; } public String getManufacturingDate() { return manufacturingDate; } public void setManufacturingDate(String manufacturingDate) { this.manufacturingDate = manufacturingDate; } public String getBrand() { return brand; } public void setBrand(String brand) { this.brand = brand; } public String getName() { return name; } public void setName(String name) { this.name = name; } } Update CarMapper.java with following code − CarMapper.java package com.tutorialspoint.mapper; import org.mapstruct.Mapper; import org.mapstruct.Mapping; import com.tutorialspoint.entity.CarEntity; import com.tutorialspoint.model.Car; import java.util.List; import java.util.UUID; @Mapper( imports = UUID.class ) public interface CarMapper { @Mapping(source = “name”, target = “name”, defaultExpression = “java(UUID.randomUUID().toString())”) @Mapping(target = “brand”, constant = “BMW”) @Mapping(source = “price”, target = “price”, numberFormat = “$#.00”) @Mapping(source = “manufacturingDate”, target = “manufacturingDate”, dateFormat = “dd.MM.yyyy”) Car getModelFromEntity(CarEntity carEntity); List<String> getListOfStrings(List<Integer> listOfIntegers); List<Car> getCars(List<CarEntity> carEntities); } Update CarMapperTest.java with following code − CarMapperTest.java package com.tutorialspoint.mapping; import static org.junit.jupiter.api.Assertions.assertEquals; import static org.junit.jupiter.api.Assertions.assertNotNull; import java.util.Arrays; import java.util.GregorianCalendar; import java.util.List; import org.junit.jupiter.api.Test; import org.mapstruct.factory.Mappers; import com.tutorialspoint.entity.CarEntity; import com.tutorialspoint.mapper.CarMapper; import com.tutorialspoint.model.Car; public class CarMapperTest { private CarMapper carMapper = Mappers.getMapper(CarMapper.class); @Test public void testEntityToModel() { CarEntity entity = new CarEntity(); entity.setPrice(345000); entity.setId(1); entity.setManufacturingDate(new GregorianCalendar(2015, 3, 5)); CarEntity entity1 = new CarEntity(); entity1.setPrice(445000); entity1.setId(2); entity1.setManufacturingDate(new GregorianCalendar(2015, 3, 5)); List<CarEntity> carEntities = Arrays.asList(entity, entity1); Car model = carMapper.getModelFromEntity(entity); assertEquals(“$345000.00”,model.getPrice()); assertEquals(entity.getId(), model.getId()); assertEquals(“BMW”, model.getBrand()); assertEquals(“05.04.2015″, model.getManufacturingDate()); List<Integer> list = Arrays.asList(1,2,3); List<String> listOfStrings = carMapper.getListOfStrings(list); List<Car> listOfCars = carMapper.getCars(carEntities); assertEquals(3, listOfStrings.size()); assertEquals(2, listOfCars.size()); } } Run the following command to test the mappings. mvn clean test Output Once command is successful. Verify the output. mvn clean test [INFO] Scanning for projects… … [INFO] — maven-surefire-plugin:2.12.4:test (default-test) @ mapping — [INFO] Surefire report directory: mvnmappingtargetsurefire-reports ——————————————————- T E S T S ——————————————————- Running com.tutorialspoint.mapping.CarMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.035 sec Running com.tutorialspoint.mapping.DeliveryAddressMapperTest Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec Running com.tutorialspoint.mapping.StudentMapperTest Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec Results : Tests run: 4, Failures: 0, Errors: 0, Skipped: 0 … Print Page Previous Next Advertisements ”;