JAVA中对list map根据map某个key值进行排序并取出前四条数据

最新推荐文章于 2024-05-14 08:45:10 发布

原创最新推荐文章于 2024-05-14 08:45:10 发布 · 8.5k 阅读

1 ·

CC 4.0 BY-SA版权

java基础专栏收录该内容

23 篇文章

订阅专栏

这段代码展示了如何在Java中对List<Map<String, Object>>根据Map的'cj'键值进行排序，并打印出排序后的前四条数据。首先创建了一个包含多个Map的List，然后使用Collections.sort()方法和自定义Comparator进行排序，最后通过subList()方法取出前四名。" 103552128,9155007,路由器配置指南：命令行操作与管理,"['网络管理', '路由器配置', '网络设备', '命令行操作', '网络基础']

import java.util.ArrayList;

import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Test {
public static void main(String[] args) {
// TODO Auto-generated method stub
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
Map<String, Object> map1 = new HashMap<String, Object>();
map1.put("name", "p");
map1.put("cj", "5");
Map<String, Object> map2 = new HashMap<String, Object>();
map2.put("name", "h");
map2.put("cj", "12");
Map<String, Object> map3 = new HashMap<String, Object>();
map3.put("name", "f");
map3.put("cj", "31");
Map<String, Object> map4 = new HashMap<String, Object>();
map4.put("name", "i");
map4.put("cj", "0");
Map<String, Object> map5 = new HashMap<String, Object>();
map5.put("name", "o");
map5.put("cj", "99");
list.add(map1);
list.add(map3);
list.add(map2);
list.add(map4);
list.add(map5);
//排序前
for (Map<String, Object> map : list) {
System.out.print(map.get("cj"));
System.out.println(map.get("name"));
}

Collections.sort(list, new Comparator<Map<String, Object>>() {
public int compare(Map<String, Object> o1, Map<String, Object> o2) {
Integer name2 = Integer.valueOf(o1.get("cj").toString()) ;
Integer name1 = Integer.valueOf(o2.get("cj").toString()) ;
return name1.compareTo(name2);
}
});

//排序后
System.out.println("-------------------");
for (Map<String, Object> map : list.subList(0, 4)) {
System.out.print(map.get("cj"));
System.out.println(map.get("name"));
}
}
}