Java代码实现按照距离、评分、订单数排序

从数据库查询出来数据集合后，可能不是我们想要的排序顺序，比如要求按照距离、评分、订单数排序

所以就需要我们在内存中进行排序

下面是用 Collections.sort()写的一个例子

import java.util.*;

public class Test {

    public static void main(String[] args) {
        List<Map<String,Object>> list = new ArrayList<>();
        Map<String, Object> map1 = new HashMap<>();
        map1.put("name","港岛煲仔饭店");
        map1.put("meter",1000);
        map1.put("grade",50);
        map1.put("count",99);
        list.add(map1);
        Map<String, Object> map2 = new HashMap<>();
        map2.put("name","兰州拉面店");
        map2.put("meter",1200);
        map2.put("grade",44);
        map2.put("count",66);
        list.add(map2);
        Map<String, Object> map3 = new HashMap<>();
        map3.put("name","西部大盘鸡店");
        map3.put("meter",600);
        map3.put("grade",49);
        map3.put("count",19);
        list.add(map3);

        sort(list,1);
        System.out.println("按距离最近排序");
        for (Map<String,Object> shop : list) {
            System.out.println(shop.get("name")+"---"+"距您"+shop.get("meter")+"米---"+"评分："+Float.valueOf(shop.get("grade").toString())/10+"分---"+"订单数："+shop.get("count")+"单");
        }
        System.out.println();

        System.out.println("按订单数最多排序");
        sort(list,2);
        for (Map<String,Object> shop : list) {
            System.out.println(shop.get("name")+"---"+"距您"+shop.get("meter")+"米---"+"评分："+Float.valueOf(shop.get("grade").toString())/10+"分---"+"订单数："+shop.get("count")+"单");
        }
        System.out.println();

        System.out.println("按评分最高排序");
        sort(list,3);
        for (Map<String,Object> shop : list) {
            System.out.println(shop.get("name")+"---"+"距您"+shop.get("meter")+"米---"+"评分："+Float.valueOf(shop.get("grade").toString())/10+"分---"+"订单数："+shop.get("count")+"单");
        }

    }

    /**
     * @description: 排序
     * @author: caoju
     */
    public static void sort(List<Map<String,Object>> BusinessList, int type){
        switch (type){
            case 1:
                Collections.sort(BusinessList , (o1, o2)-> {
                    Integer o1Value = Integer.valueOf(o1.get("meter").toString());
                    Integer o2Value = Integer.valueOf(o2.get("meter").toString());
                    return o1Value.compareTo(o2Value);
                });
                break;
            case 2:
                Collections.sort(BusinessList , (o1,o2)-> {
                    Integer o1Value = Integer.valueOf(o1.get("count").toString());
                    Integer o2Value = Integer.valueOf(o2.get("count").toString());
                    return o2Value.compareTo(o1Value);
                });
                break;
            case 3:
                Collections.sort(BusinessList , (o1,o2)-> {
                    Integer o1Value = Integer.valueOf(o1.get("grade").toString());
                    Integer o2Value = Integer.valueOf(o2.get("grade").toString());
                    return o2Value.compareTo(o1Value);
                });
                break;
        }
    }

}

看下最后执行的结果：

可以看到已经按照想排的顺序进行排序了