java中如何使用字段对对象数组进行排序

1.实现Comparator进行排序

创建需要排序对象

/**
 * @author wangli
 * @create 2022-08-17 17:17
 */
@Data
public class TotalNumDto {
    @ApiModelProperty("工单总量")
    private Integer workNum;
 
    @ApiModelProperty("同比数")
    private Integer yoyNum;
 
    @ApiModelProperty("环比数")
    private Integer qoqNum;
}

实现Comparator的compare方式实现排序

    @Test
    public void test2(){
        List totalNumDtoList = new ArrayList<>();
        for (int i = 0; i < 3; i++) {
            TotalNumDto totalNumDto = new TotalNumDto();
            totalNumDto.setWorkNum(i*2+1);
            totalNumDtoList.add(totalNumDto);
        }
        System.out.println("排序前 = " + totalNumDtoList);
        Collections.sort(totalNumDtoList, new Comparator() {
            @Override
            public int compare(TotalNumDto o1, TotalNumDto o2) {
                //顺序
                //return o1.getWorkNum()-o2.getWorkNum();
                //逆序
                return o2.getWorkNum()-o1.getWorkNum();
            }
        });
        System.out.println("排序后 = " + totalNumDtoList);
    }

打印结果如下

排序前 = [

TotalNumDto(workNum=1, yoyNum=null, qoqNum=null),

TotalNumDto(workNum=3, yoyNum=null, qoqNum=null),

TotalNumDto(workNum=5, yoyNum=null, qoqNum=null)]
排序后 = [

TotalNumDto(workNum=5, yoyNum=null, qoqNum=null),

TotalNumDto(workNum=3, yoyNum=null, qoqNum=null),

TotalNumDto(workNum=1, yoyNum=null, qoqNum=null)]

比较它的两个参数的顺序。返回负整数、零或正整数，因为第一个参数小于、等于或大于第二个

当compare方法返回1时需要交换这两个数的位置，通过算法循环从而达到不断交换位