技術標籤：筆記javajava

在程式碼開發中，經常會遇到不同實體類之間的欄位copy，以前經常用到的有通過set賦值或者apache、spring的BeanUtils.copyProperties()，原生的set賦值隨便速度比較快，但是當欄位多的時候，就顯得比較麻煩了，每個都要自己手動set一下值，而apache、spring的BeanUtils.copyProperties()可以解決這種欄位比較多的情況，但是這種方式有個弊端，就是，欄位的型別和名稱都必須一樣才可以，否則copy時會被忽略掉。知道接觸了一種新的方式，使用MapStruct方式。

加入MapStruct的依賴jar包

    <properties>
        <mapstruct.version>1.2.0.Final</mapstruct.version>
    </properties>

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-jdk8</artifactId>
            <version>${mapstruct.version}</version>
        </dependency>

        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>${mapstruct.version}</version>
        </dependency>
 

建立實體類User

public class User {
    private Integer id;
    private String userName;
    private String desc;
    private Integer age;
    private Double salary;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Double getSalary() {
        return salary;
    }

    public void setSalary(Double salary) {
        this.salary = salary;
    }
}
 

建立UserDTO類

public class UserDTO {
    private Integer id;
    private String userName;
    private Date createDate;
    private String remark;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Date getCreateDate() {
        return createDate;
    }

    public void setCreateDate(Date createDate) {
        this.createDate = createDate;
    }

    public String getRemark() {
        return remark;
    }

    public void setRemark(String remark) {
        this.remark = remark;
    }

    public UserDTO() {
    }

    @Override
    public String toString() {
        return "UserDTO{" +
                "id=" + id +
                ", userName='" + userName + '\'' +
                ", createDate=" + createDate +
                ", remark='" + remark + '\'' +
                '}';
    }

建立介面UserMapStruct

import org.mapstruct.MapMapping;
import org.mapstruct.Mapper;
import org.mapstruct.Mapping;
import org.mapstruct.Mappings;
import org.mapstruct.factory.Mappers;
@Mapper
public interface UserMapStruct {

    UserMapStruct INSTANCE = Mappers.getMapper(UserMapStruct.class);

    @Mappings({
        @Mapping(source = "desc",target = "remark")
    })
    public UserDTO userToDto(User user);
}

程式碼測試

public class TestUserMapStruct {

    public static void main(String[] args) {

        User user = new User();
        user.setId(1000);
        user.setAge(21);
        user.setDesc("測試複製工具");
        user.setSalary(400.44);
        user.setUserName("張三");

        UserDTO userDTO = UserMapStruct.INSTANCE.userToDto(user);
        System.out.println(userDTO.toString());

    }
}

輸出結果