工具类----实体类与DTO之间的双向转换

package com.toolconclusion.transition;

import org.springframework.beans.BeanUtils;

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

/**
 * @Author: Sun
 * @DateTime: 2025/4/1 10:53
 * @Description: 实体和dto转换工具
 **/
public class EntityConverter {
    public static  D entity2DTO(E entity, Class dtoClass) {
        return convertBean(entity, dtoClass);
    }

    private static  B2 convertBean(B1 b1, Class b2Class) {
        B2 b2 = null;
        if (b1 == null) {
            return null;
        }
        try {
            b2 = b2Class.newInstance();
            BeanUtils.copyProperties(b1, b2);
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
        return b2;
    }

    public static  List entity2DTO(List entityList, Class dtoClass) {
        Stream stream = entityList.stream();

        return stream.map(e->entity2DTO(e,dtoClass)).collect(Collectors.toList());
    }

}

使用：

实体类：
public class User {
    private Long id;
    private String name;
    private String email;
    
    // 构造方法、getter和setter省略
}


DTO
public class UserDTO {
    private Long id;
    private String name;
    private String email;
    
    // 构造方法、getter和setter省略
}

public class Main {
    public static void main(String[] args) {
        // 单个对象转换
        User user = new User(1L, "张三", "[email protected]");
        UserDTO userDTO = EntityConverter.entity2DTO(user, UserDTO.class);
        System.out.println("单个转换结果: " + userDTO);
        
        // DTO转单个实体
        UserDTO userDTO = new UserDTO(1L, "张三", "[email protected]");
        User user = EntityConverter.entity2DTO(userDTO, User.class);
        System.out.println("DTO转实体结果: " + user);

        // 集合对象转换
        List users = Arrays.asList(
            new User(1L, "张三", "[email protected]"),
            new User(2L, "李四", "[email protected]")
        );
        
        List userDTOs = EntityConverter.entity2DTO(users, UserDTO.class);
        System.out.println("集合转换结果: " + userDTOs);
    }
}