Spring：BeanUtils工具类-copyProperties使用

1 使用

BeanUtils.copyProperties使用：

Drink实体类：

package com.xiaoxu.entity;

import lombok.Getter;
import lombok.Setter;

import java.math.BigDecimal;
import java.util.Date;


@Getter
@Setter
public class Drink {
    private String drinkName;
    private BigDecimal drinkPrice;
    private long count;
    private Date drinkTime;
    private Date gmtCreate;
    private Date gmtModified;
}

DrinkDto实体类：

package com.xiaoxu.dto;

import lombok.Setter;
import lombok.ToString;

import java.math.BigDecimal;


@ToString
@Setter
public class DrinkDto {
    private String name;
    private BigDecimal drinkPrice;
    private long count;
}

Drink转DrinkDto的转换类：

package com.xiaoxu.convertor;

import com.xiaoxu.dto.DrinkDto;
import com.xiaoxu.entity.Drink;
import org.springframework.beans.BeanUtils;

import java.math.BigDecimal;
import java.util.Date;


public class Drink2DrinkDtoConvertor {
    public static void main(String[] args) {
        Drink d = new Drink();
        d.setDrinkName("milk");
        d.setDrinkPrice(new BigDecimal("12.5"));
        d.setDrinkTime(new Date());
        d.setCount(100L);
        d.setGmtCreate(new Date());
        d.setGmtModified(new Date());

        System.out.println(Drink2DrinkDtoConvertor.convertor(d, 1));
        System.out.println(Drink2DrinkDtoConvertor.convertor(d, 2));
    }
    static DrinkDto convertor(Drink drink,int flag){
        DrinkDto drinkDto = new DrinkDto();
        switch(flag){
            case 1:
                BeanUtils.copyProperties(drink,drinkDto);
                break;
            case 2:
                BeanUtils.copyProperties(drink,drinkDto, "count");
                break;
            default:
                System.out.println("请检查flag值只能为1、2.");
        }
        return drinkDto;
    }
}

执行结果如下：

DrinkDto(name=null, drinkPrice=12.5, count=100)
DrinkDto(name=null, drinkPrice=12.5, count=0)

使用BeanUtils.copyProperties时，object对象须有setter和getter方法，target对象要setter方法，如此才可进行bean的属性copy。BeanUtils.copyProperties会将object中和target中同名属性直接copy过去，如果某些字段不需要copy，使用第三个String…参数即可，如上传入count后，那么count将被忽略，不会被copy过去。