mapstruct实体类转换工具

文章介绍了如何搭建MapStruct环境,包括添加依赖和相关插件配置。接着展示了Car和CarDto两个类的定义,以及使用MapStruct的Mapper接口进行对象转换的方法。最后提供了一个测试类MsTest来验证转换功能。

1、mapstruct环境搭建

1、导入依赖文件

	<properties>
        <org.mapstruct.version>1.4.2.Final</org.mapstruct.version>
    </properties>


<!--mapStruct依赖-->
     <dependency>
         <groupId>org.mapstruct</groupId>
         <artifactId>mapstruct</artifactId>
         <version>${org.mapstruct.version}</version>
     </dependency>
     <dependency>
         <groupId>org.mapstruct</groupId>
         <artifactId>mapstruct-processor</artifactId>
         <scope>provided</scope>
         <version>1.2.0.Final</version>
     </dependency>

<!--mapStruct相关插件-->
	<build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <!-- depending on your project -->
                    <target>1.8</target>
                    <!-- depending on your project -->
                    <annotationProcessorPaths>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>${org.mapstruct.version}</version>
                        </path>
                        <!-- other annotation processors -->
                    </annotationProcessorPaths>
                </configuration></plugin></plugins>
    </build>

2、创建car类

package cn.itedus.lottery.test.mapstruct;

import cn.itedus.lottery.test.mapstruct.entity.Brand;

/**
 * @author cl
 */
public class Car {

    private String make;

    private int numberOfSeats;

    private Brand brand;

    public Car(String make, int numberOfSeats, Brand brand) {
        this.make = make;
        this.numberOfSeats = numberOfSeats;
        this.brand = brand;
    }

    public Car() {
    }

    public Car(String make, int numberOfSeats) {
        this.make = make;
        this.numberOfSeats = numberOfSeats;
    }

    public String getMake() {
        return make;
    }

    public int getNumberOfSeats() {
        return numberOfSeats;
    }

    public void setMake(String make) {
        this.make = make;
    }

    public void setNumberOfSeats(int numberOfSeats) {
        this.numberOfSeats = numberOfSeats;
    }

    public Brand getBrand() {
        return brand;
    }

    public void setBrand(Brand brand) {
        this.brand = brand;
    }

    @Override
    public String toString() {
        return "Car{" +
                "make='" + make + '\'' +
                ", numberOfSeats=" + numberOfSeats +
                ", brand=" + brand +
                '}';
    }
}


3、创建carDto类

package cn.itedus.lottery.test.mapstruct;

import cn.itedus.lottery.test.mapstruct.entity.Brand;

/**
 * @author cl
 */
public class CarDto {

    private String make;

    private int seatCount;

    private String type;

    private Brand carBrand;



    public CarDto() {
    }

    public CarDto(String make, int seatCount, String type) {
        this.make = make;
        this.seatCount = seatCount;
        this.type = type;
    }


    public String getMake() {
        return make;
    }

    public int getSeatCount() {
        return seatCount;
    }

    public String getType() {
        return type;
    }

    public void setMake(String make) {
        this.make = make;
    }

    public void setSeatCount(int seatCount) {
        this.seatCount = seatCount;
    }

    public void setType(String type) {
        this.type = type;
    }

    public CarDto(String make, int seatCount, String type, Brand carBrand) {
        this.make = make;
        this.seatCount = seatCount;
        this.type = type;
        this.carBrand = carBrand;
    }

    public Brand getCarBrand() {
        return carBrand;
    }

    public void setCarBrand(Brand carBrand) {
        this.carBrand = carBrand;
    }

    @Override
    public String toString() {
        return "CarDto{" +
                "make='" + make + '\'' +
                ", seatCount=" + seatCount +
                ", type='" + type + '\'' +
                ", carBrand=" + carBrand +
                '}';
    }
}


4、创建CarMapper类

package cn.itedus.lottery.test.mapstruct;

import org.mapstruct.Mapper;
import org.mapstruct.Mapping;
import org.mapstruct.Mappings;
import org.mapstruct.factory.Mappers;

/**
 * @author cl
 */
@Mapper
public interface CarMapper {

    CarMapper instantce = Mappers.getMapper(CarMapper.class);

    /**
     * Car -> CarDto转换
     *
     * 将源类Car中的字段numberOfSeats转换到CarDto中的seatCount字段中
     *
     * 表达式如果想自动提示的话,则需要安装mapstruct support插件
     *
     * @param car
     * @return
     */
    @Mapping(source = "numberOfSeats", target = "seatCount")
    @Mapping(target = "type",constant = "bbb")
    CarDto carToCarDto(Car car);


    @Mappings({@Mapping(source = "numberOfSeats", target = "seatCount"),
            @Mapping(target = "type",constant = "bbb"),
            @Mapping(source = "brand",target = "carBrand")
    })
    CarDto carToCarDtoV2(Car car);

}


5、测试类

public class MsTest {

    @Test
    public void test_ms(){
        CarMapper instantce = CarMapper.instantce;

        Car car = new Car();
        car.setMake("from");
        car.setNumberOfSeats(100);
        car.setBrand(new Brand("宝马"));
        CarDto carDto = instantce.carToCarDtoV2(car);
        System.out.println(car);
        System.out.println(carDto);
    }
}

测试结果:
在这里插入图片描述

### Java BO 和 VO 实体类转换工具类 为了简化BO(业务对象)和VO(值对象)之间的转换过程,可以利用MapStruct这样的映射框架来减少手动编写转换逻辑的工作量。相比于传统的手写转换器方式,这种方式不仅减少了代码冗余度还提高了可维护性和扩展性。 #### 使用 MapStruct 进行实体类转换 首先,在项目中加入MapStruct依赖: ```xml <dependency> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-jdk8</artifactId> <version>1.5.2.Final</version> </dependency> <!-- 如果使用Maven编译插件 --> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.8.0</version> <configuration> <source>1.8</source> <target>1.8</target> <annotationProcessorPaths> <path> <groupId>org.mapstruct</groupId> <artifactId>mapstruct-processor</artifactId> <version>1.5.2.Final</version> </path> </annotationProcessorPaths> </configuration> </plugin> </plugins> </build> ``` 定义两个简单的实体类`UserBO`和`UserVO`作为例子: ```java public class UserBO { private Long id; private String name; // getter and setter methods... } public class UserVO { private Integer userId; // 不同类型的字段也可以被自动处理 private String userName; // getter and setter methods... } ``` 创建接口并配置Mapper规则: ```java import org.mapstruct.Mapper; import org.mapstruct.Mapping; import org.mapstruct.factory.Mappers; @Mapper public interface UserConverter { UserConverter INSTANCE = Mappers.getMapper(UserConverter.class); @Mapping(source = "id", target = "userId") // 映射不同名称的属性 @Mapping(source = "name", target = "userName") // 同样适用于相同名称的情况 UserVO boToVo(UserBO userBo); List<UserVO> bosToVos(List<UserBO> list); // 支持集合类型转换 } ``` 通过上述设置之后就可以轻松实现从`UserBO`到`UserVO`以及列表形式的数据转换了[^1]。 ```java // 示例用法 List<UserBO> userList = ... ; // 获取数据源 List<UserVO> voList = UserConverter.INSTANCE.bosToVos(userList); ``` 这种做法能够有效降低因字段变化带来的影响,并且保持良好的性能表现。
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