JAVA中对list map根据map某个key值进行排序

亦凉 2022-02-15 02:53 447阅读 0赞

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 javaListMapSort {
        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");
            list.add(map1);
            list.add(map3);
            list.add(map2);
            //排序前 
            for (Map<String, Object> map : list) {
                System.out.println(map.get("cj"));
            }
            Collections.sort(list, new Comparator<Map<String, Object>>() {
                public int compare(Map<String, Object> o1, Map<String, Object> o2) {
                    Integer name1 = Integer.valueOf(o1.get("cj").toString()) ;//name1是从你list里面拿出来的一个 
                    Integer name2 = Integer.valueOf(o2.get("cj").toString()) ; //name1是从你list里面拿出来的第二个name
                    return name1.compareTo(name2);
                }
            });
            //排序后 
            System.out.println("-------------------");
            for (Map<String, Object> map : list) {
                System.out.println(map.get("cj"));
            }
        }
    }