[JAVA] Bean mapping with MapStruct Part 2

Continuation of the last time http://qiita.com/kentama/items/09a8573bd5d0831b470e

Create one bean from multiple beans

Bean

public class Hoge {
    private String hoge1;
    private String hoge2;
    private String hoge3;
    private String hoge4;

    // constructor/getter/setter
}

public class Fuga {
    public String fuga1;
    public String fuga2;

    // constructor/getter/setter
}

public class Piyo {
    public String piyo1;
    public String piyo2;

    // constructor/getter/setter
}

Creating a Mapper

Specify which bean field to use in the @Mapping source attribute.

@Mapper
public interface HogeMapper {
    HogeMapper INSTANCE = Mappers.getMapper(HogeMapper.class);

    @Mapping(target = "hoge1", source = "fuga.fuga1")
    @Mapping(target = "hoge2", source = "fuga.fuga2")
    @Mapping(target = "hoge3", source = "piyo.piyo1")
    @Mapping(target = "hoge4", source = "piyo.piyo2")
    public Hoge map(Fuga fuga, Piyo piyo);
}

Run

Fuga fuga = new Fuga("a", "b");
Piyo piyo = new Piyo("c", "d");
Hoge hoge = HogeMapper.INSTANCE.map(fuga, piyo);

System.out.println(hoge.getHoge1()); // a
System.out.println(hoge.getHoge2()); // b
System.out.println(hoge.getHoge3()); // c
System.out.println(hoge.getHoge4()); // d

Update the created bean

Creating a Mapper

Add @MappingTarget to the argument to be updated.

@Mapper
public interface UpdateMapper {
    UpdateMapper INSTANCE = Mappers.getMapper(UpdateMapper.class);

    @Mapping(target = "hoge1", source = "fuga1")
    @Mapping(target = "hoge2", source = "fuga2")
    @Mapping(target = "hoge3", source = "fuga1")
    @Mapping(target = "hoge4", source = "fuga2")
    public void updateHogeFromFuga(Fuga fuga, @MappingTarget Hoge hoge);
}

Run

Fuga fuga = new Fuga("a", "b");
Hoge hoge = new Hoge("1", "2", "3", "4");
UpdateMapper.INSTANCE.updateHogeFromFuga(fuga, hoge);

System.out.println(hoge.getHoge1()); // a
System.out.println(hoge.getHoge2()); // b
System.out.println(hoge.getHoge3()); // a
System.out.println(hoge.getHoge4()); // b

Add custom method

Method using default method

You can define a default method and add your own mapping method.

@Mapper
public interface FooBarMapper {
    FooBarMapper INSTANCE = Mappers.getMapper(FooBarMapper.class);

    default Bar fooToBar(Foo foo) {
        Bar bar = new Bar();
        bar.setBar1(foo.getFoo1());
        bar.setBar2(foo.getFoo2());
        return bar;
    }
}

Method using abstract class

It has been created in the interface class so far, but it can also be created in the abstract class.

@Mapper
public abstract class FooBarMapper {
    public Bar fooToBar(Foo foo) {
        Bar bar = new Bar();
        bar.setBar1(foo.getFoo1());
        bar.setBar2(foo.getFoo2());
        return bar;
    }
}

When using it, it is necessary to explicitly create an instance.

FooBarMapperImpl mapper = new FooBarMapperImpl();
Bar bar = mapper.fooToBar(new Foo("AIUEO", "Kakikukeko"));

System.out.println(bar.getBar1()); //AIUEO
System.out.println(bar.getBar2()); //Kakikukeko

Next time.