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MapStruct allows to call a conversion method for customized logic. We can use expression to achieve the same where we can pass any java object and call its method to do the conversion.
Syntax
@Mapping(target = "target-property", expression = "java(target-method())")
Here
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target-property − the property for which we are doing the mapping.
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expression − mapper will call the java method written in the expression.
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target-method − target-method is the method to be called. In case method is present in different class, use new class-name.target-method()
Example
Open project mapping as updated in Mapping Using dateFormat 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 java.text.SimpleDateFormat; import java.util.Date; import java.util.GregorianCalendar; 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(target = "manufacturingDate", expression = "java(getManufacturingDate(carEntity.getManufacturingDate()))") Car getModelFromEntity(CarEntity carEntity); default String getManufacturingDate(GregorianCalendar manufacturingDate) { Date d = manufacturingDate.getTime(); SimpleDateFormat sdf = new SimpleDateFormat( "dd.MM.yyyy" ); return sdf.format( d ); } }
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 ...
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