java类映射转换框架MapStrcut

类之间转换框架 mapStruct

maven 中引用 jar

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>${org.projectlombok.version}</version>
</dependency>

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId> <!-- use mapstruct-jdk8 for Java 8 or higher -->
    <version>${org.mapstruct.version}</version>
</dependency>

配置 maven-compiler-plugin

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.6.0</version>
    <configuration>
        <source>${java.version}</source> <!-- or higher, depending on your project -->
        <target>${java.version}</target> <!-- or higher, depending on your project -->
        <annotationProcessorPaths>
            <!-- 如果使用lombok, 需要将lombok放在 mapstruct之前 -->
            <path>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${org.projectlombok.version}</version>
            </path>
            <path>
                <groupId>org.mapstruct</groupId>
                <artifactId>mapstruct-processor</artifactId>
                <version>${org.mapstruct.version}</version>
            </path>
        </annotationProcessorPaths>
        <compilerArgs>
            <!-- 不生成impl生成的时间 -->
            <arg>-Amapstruct.suppressGeneratorTimestamp=true</arg>
            <!-- 生成的impl类将带有 @Component spring注解 -->
            <arg>-Amapstruct.defaultComponentModel=spring</arg>
        </compilerArgs>
    </configuration>
</plugin>

使用

编写需要转换的类

转换 CustomerDo -> CustomerDto -> CustomerVo

@Data
@AllArgsConstructor
public class CustomerDo {
    private String firstName;
    private String lastName;
}

@Data
public class CustomerDto {
    private String forename;
    private String surname;
}

@Data
public class CustomerVo {
    private String firstName;
    private String lastName;
}

编写转换 Mapper (非Mybatis中的Mapper)

@org.mapstruct.Mapper
public interface CustomerMapper {

    /** 其实就是 CustomerMapper 实例对象 */
    CustomerMapper INSTANCE = Mappers.getMapper(CustomerMapper.class);

    /**
     * CustomerDo 转换成 CustomerDto
     *
     * \@org.mapstruct.Mapping
     * source: 源类的属性
     * target: 目标类的属性
     * 如果两个类中的属性名不相同, 则需要进行 source -> target 进行映射;
     * 如果两个类属性名完全相同, 则无需添加 \@org.mapstruct.Mapping, MapStruct 自动相同名称进行映射
     *
     * @param customerDo 源数据
     * @return 转换之后数据
     */
    @Mapping(source = "firstName", target = "forename")
    @Mapping(source = "lastName", target = "surname")
    CustomerDto customerToDto(CustomerDo customerDo);

    /** CustomerDto 转换成 CustomerVo */
    @Mapping(source = "forename", target = "firstName")
    @Mapping(source = "surname", target = "lastName")
    CustomerVo customerToVo(CustomerDto dto);

}

编译结果

执行 mvn clean compile -Dmaven.test.skip=true, 结果如下:

@Generated(
    value = "org.mapstruct.ap.MappingProcessor",
    comments = "version: 1.4.2.Final, compiler: javac, environment: Java 1.8.0_271 (Oracle Corporation)"
)
// <arg>-Amapstruct.defaultComponentModel=spring</arg> 作用的结果, 如果不想用spring, 可以去掉
@Component
public class CustomerMapperImpl implements CustomerMapper {

    @Override
    public CustomerDto customerToDto(CustomerDo customerDo) {
        if ( customerDo == null ) {
            return null;
        }

        CustomerDto customerDto = new CustomerDto();

        customerDto.setForename( customerDo.getFirstName() );
        customerDto.setSurname( customerDo.getLastName() );

        return customerDto;
    }

    @Override
    public CustomerVo customerToVo(CustomerDto dto) {
        if ( dto == null ) {
            return null;
        }

        CustomerVo customerVo = new CustomerVo();

        customerVo.setFirstName( dto.getForename() );
        customerVo.setLastName( dto.getSurname() );

        return customerVo;
    }
}

测试

/**
 * @author Chris
 * @version 1.0.0
 * @date 2021/02/02
 */
class CustomerMapperTest {
    @Test
    public void test1() {
        System.out.println("===== test1 =====");
        CustomerDo customerDo = new CustomerDo("Jacky", "Brown");
        final CustomerDto customerDto = CustomerMapper.INSTANCE.customerToDto(customerDo);
        System.out.println(customerDto);

        final CustomerVo customerVo = CustomerMapper.INSTANCE.customerToVo(customerDto);
        System.out.println(customerVo);
    }
}

结果正常, 测试结束.

因为 MapStrcut 编译时生成的类中直接使用get/set做转换处理的.所以理论上性能应该是所有映射框架中最好的. 其他映射框架如 orika,beanutils. 如果做类之间转换, 推荐使用 MapStruct 及 orika