Mapstruct 简明教程

MapStruct - Using Builder

MapStruct 允许使用 Builder。我们可以使用 Builder 框架或可以自定义 Builder。在以下示例中，我们使用自定义 Builder。

MapStruct allows to use Builders. We can use Builder frameworks or can use our custom builder. In below example, we are using a custom builder.

Example

在 Eclipse 中打开项目映射为 Mapping Direct Fields 中的更新内容。

Open project mapping as updated in Mapping Direct Fields chapter in Eclipse.

使用以下代码更新 Student.java −

Update Student.java with following code −

Student.java

package com.tutorialspoint.model;

public class Student {
   private final String name;
   private final int id;

   protected Student(Student.Builder builder) {
      this.name = builder.name;
      this.id = builder.id;
   }
   public static Student.Builder builder() {
      return new Student.Builder();
   }
   public static class Builder {
      private String name;
      private int id;
      public Builder name(String name) {
         this.name = name;
         return this;
      }
      public Builder id(int id) {
         this.id = id;
         return this;
      }
      public Student create() {
         return new Student( this );
      }
   }
   public String getName() {
      return name;
   }
   public int getId() {
      return id;
   }
}

使用以下代码更新 StudentMapper.java −

Update 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 {
   Student getModelFromEntity(StudentEntity studentEntity);
   @Mapping(target="id", source="id")
   @Mapping(target="name", source="name")
   StudentEntity getEntityFromModel(Student student);
}

使用以下代码更新 StudentMapperTest.java −

Update 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.entity.SubjectEntity;
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.setName("John");
      entity.setId(1);
      Student model = studentMapper.getModelFromEntity(entity);
      assertEquals(entity.getName(), model.getName());
      assertEquals(entity.getId(), model.getId());
   }
   @Test
   public void testModelToEntity() {
      Student.Builder builder = Student.builder().id(1).name("John");
      Student model = builder.create();
      StudentEntity entity = studentMapper.getEntityFromModel(model);
      assertEquals(entity.getName(), model.getName());
      assertEquals(entity.getId(), model.getId());
   }
}

运行以下命令以测试映射。

Run the following command to test the mappings.

mvn clean test

Output

命令成功后。验证输出。

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: \mvn\mapping\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.tutorialspoint.mapping.DeliveryAddressMapperTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.005 sec
Running com.tutorialspoint.mapping.StudentMapperTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.002 sec

Results :

Tests run: 3, Failures: 0, Errors: 0, Skipped: 0
...