使用mapstruct实现对象拷贝

Mapstructs实现对象拷贝:

单个对象拷贝(默认只拷贝属性名和方法名都相同的值)，当属性名或者属性类型不同时可使用@Mapping注解进行映射
List拷贝
List嵌套List拷贝

代码示例

import lombok.AllArgsConstructor;
import lombok.Data;
import org.mapstruct.Mapper;
import org.mapstruct.Mapping;
import org.mapstruct.Mappings;
import org.mapstruct.factory.Mappers;

import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Mapstructs实现实现拷贝：
 *  1、单个对象拷贝
 *  2、List拷贝
 *  3、List嵌套拷贝
 *  4、自定义拷贝规则
 * MapSturct 是一个生成类型安全， 高性能且无依赖的 JavaBean 映射代码的注解处理器，编译后会生产相应代码，路径为
 * target/generated-sources/annotations/BeanCopierUtilImpl.java
 */
@Mapper
interface BeanCopierUtil {
    BeanCopierUtil INSTANCE = Mappers.getMapper(BeanCopierUtil.class);

    /**
     * 单个对象转化
     * @param userDto
     * @return
     */
    @Mappings({
            @Mapping(target = "userName", source = "user_name")
    })
    UserVo toVo(UserDto userDto);
    /**
     * List集合拷贝,支持嵌套，需要定义UserDto到UserVo的转化
     */
    List<UserVo> toVo(List<UserDto> userList);
}

public class MapstructTest {
    public static void main(String[] args) {
        List<UserDto> userDtoList = Stream.of(
                new UserDto("1","张三",5),
                new UserDto("2","李四",6)
        ).collect(Collectors.toList());
        List<UserVo> result = BeanCopierUtil.INSTANCE.toVo(userDtoList);
        System.out.println(userDtoList);
        System.out.println(result);

    }
}

@Data
@AllArgsConstructor
class UserDto {
    private String id;
    private String user_name;
    private Integer user_age;
}

@Data
class UserVo {
    private String id;
    private String userName;
    private Integer userAge;
}

运行结果

[UserDto(id=1, user_name=张三, user_age=5), UserDto(id=2, user_name=李四, user_age=6)]
[UserVo(id=1, userName=张三, userAge=null), UserVo(id=2, userName=李四, userAge=null)]

Pom.xml引入依赖包

<properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <mapstruct.version>1.5.5.Final</mapstruct.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>${mapstruct.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>${mapstruct.version}</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>