Lambad sort 多条件排序（实战）

最新推荐文章于 2023-07-10 17:12:47 发布

tian.tian

最新推荐文章于 2023-07-10 17:12:47 发布

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本文链接：https://blog.youkuaiyun.com/li_tiantian/article/details/103823691

本文介绍了使用Lambda表达式进行多条件排序的实际操作。首先，详细阐述了实体类的设计，接着通过具体示例展示了如何在Java中运用Lambda进行复杂排序的实现过程。

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一、实体类

import java.io.Serializable;
import lombok.Data;
@Data
public class Contract implements Serializable {
    private Integer contractCode;
    private Byte isDeleted;
}

二、示例


import static java.util.Comparator.comparing;

import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;

import org.junit.Test;

import com.alibaba.fastjson.JSON;

public class LambdaSortTest {

@Test
    public void sortTest1() {
        List<Contract> contracts = getContracts();
        System.out.println(JSON.toJSONString(contracts));
        
        // order by contractCode asc, isDelete desc;
        contracts.sort(comparing(Contract::getContractCode)
                                 .thenComparing(comparing(Contract::getIsDeleted).reversed()));
        System.out.println(JSON.toJSONString(contracts));
        
        // order by contractCode desc, isDelete asc;
        contracts.sort(comparing(Contract::getContractCode).reversed()
                       .thenComparing(Comparator.comparing(Contract::getIsDeleted)));
        System.out.println(JSON.toJSONString(contracts));
    }

    @Test
    public void sortTest2() {
        List<Contract> contracts = getContracts();
        System.out.println(JSON.toJSONString(contracts));
        
        // order by contractCode asc, isDelete desc;
        contracts.sort((Contract c1, Contract c2) -> {
            int result = c1.getContractCode().compareTo(c2.getContractCode());
            if (result != 0) {
                if (result == 1) {
                    return 1;
                }
            } else {
                result = c1.getIsDeleted() - c2.getIsDeleted();
                if (result == 1) {
                    return -1;
                }
            }
            return 0;
        });
        
        System.out.println(JSON.toJSONString(contracts));
    }
    
    private List<Contract> getContracts() {
        List<Contract> contracts = new ArrayList<>();
        contracts.add(getContract(10001, (byte) 0));
        contracts.add(getContract(10001, (byte) 1));
        contracts.add(getContract(10002, (byte) 0));
        contracts.add(getContract(10002, (byte) 1));
        contracts.add(getContract(10003, (byte) 1));
        contracts.add(getContract(10003, (byte) 0));
        return contracts;
    }

    private Contract getContract(Integer contractCode, Byte isDeleted) {
        Contract c = new Contract();
        c.setContractCode(contractCode);
        c.setIsDeleted(isDeleted);
        return c;
    }
}