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反射的定义、机制等等概念网上有很多，这里就不做过多的赘述了，本文主要介绍通过反射机制获取对象中一个list属性的值，并将值赋值到另一个对象中。

上代码:

1.实体类

package com.study.reflex;

import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
public class Women {
    private Integer id;

    private String name;

    private String address;

    public Women(Integer id, String name, String address) {
        this.id = id;
        this.name = name;
        this.address = address;
    }
}

package com.study.reflex;

import lombok.Data;

@Data
public class User {
    private Integer id;

    private String name;

    private String address;

    public User() {
    }

    public User(Integer id, String name, String address) {
        this.id = id;
        this.name = name;
        this.address = address;
    }
}

说明:两个实体类的字段要一致才能进行下面的操作

2.公共基类

public interface BaseResponse {

}

3.实现类

package com.study.reflex;

import lombok.Data;

import java.util.List;

@Data
public class TargeResponse  implements BaseResponse{
    private int pageNumber;

    private int pageSize;
    private List<User> itmes;

}

package com.study.reflex;

import lombok.Data;

import java.util.List;

@Data
public class WomenResponse implements BaseResponse{
    private int pageNumber;

    private int pageSize;

    private List<Women> items;

}

4.响应基类

package com.study.reflex;

import lombok.Data;

@Data
public class BaseResult<T> {

    private boolean success;

    private int code;

    private T data;
}

测试类

package com.lubang.test;

import com.alibaba.fastjson.JSON;
import com.study.reflex.*;
import org.junit.Test;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class ReflexTest {

    @Test
    public void reflexTest() throws Exception {
        WomenResponse womenResponse = buildSource();
        BaseResult<BaseResponse> sourceResult = new BaseResult<>();
        sourceResult.setCode(200);
        sourceResult.setSuccess(true);
        sourceResult.setData(womenResponse);

        System.out.println("source:"+JSON.toJSONString(sourceResult));
        //将ReflexResponse中list中的对象值赋值给TargeResponse
        BaseResult<TargeResponse> tar = buildTargeByReflex(sourceResult,Women.class);
        System.out.println("targe:"+ JSON.toJSONString(tar));

    }

	//这里使用泛型适用性更广
    private <T,R> BaseResult<TargeResponse> buildTargeByReflex(BaseResult<T> baseResult, Class<R> targeClass) throws Exception {
        TargeResponse targeResponse = new TargeResponse();
        if(null != baseResult){
            List<User> list = new ArrayList<>();
            //获取baseResult中data数据即:BaseResponse
            T data = baseResult.getData();
            Class<?> aClass = data.getClass();
            //BaseResponse中items属性
            Field items = aClass.getDeclaredField("items");
            items.setAccessible(true);
            Object obj = items.get(data);
            //将object转成list
            List<R> tarList = objCastList(obj,targeClass);
            //遍历list
            for (R r : tarList) {
                Class<?> rClass = r.getClass();
                Field[] rFileds = rClass.getDeclaredFields();

                //new 一个目标对象
                User user = new User();
                Class<? extends User> userClass = user.getClass();
                //取目标对象所有属性名称
                List<String> userFiledNames = Arrays.stream(userClass.getDeclaredFields()).map(f -> f.getName()).collect(Collectors.toList());
                for (Field rFiled : rFileds) {
                    //取值
                    rFiled.setAccessible(true);
                    String name = rFiled.getName();
                    Object vaule = rFiled.get(r);

                    //赋值
                    if(userFiledNames.contains(name)){
                        Field targeField = userClass.getDeclaredField(name);
                        targeField.setAccessible(true);
                        targeField.set(user,vaule);
                    }
                }
                list.add(user);
            }
            targeResponse.setItmes(list);
        }
        BaseResult<TargeResponse> result = new BaseResult<>();
        result.setData(targeResponse);
        return result;
    }

    private <R> List<R> objCastList(Object obj, Class<R> clazz) {
        List<R> list = new ArrayList<>();
        if(obj instanceof List<?>){
            for (Object o :(List<?>)obj){
                list.add(clazz.cast(o));
            }
        }
        return list;
    }

    private WomenResponse buildSource() {
        Women women = new Women(1,"zhangsan","北海道");
        List<Women> list = new ArrayList<>();
        list.add(women);
        WomenResponse source = new WomenResponse();
        source.setItems(list);
        return source;
    }
}

测试结果:

在这里插入图片描述