Java中对list map根据map某个key值进行排序的方法

package test;

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 java_ListMapSort {
  public static void main(String[] args) {
    // TODO Auto-generated method stub 
    List<Map<String,  >> list = new ArrayList<Map<String,  >>();
    Map<String,  > map1 = new HashMap<String,  >();
    map1.put("name", "p");
    map1.put("cj", "5");
    Map<String,  > map2 = new HashMap<String,  >();
    map2.put("name", "h");
    map2.put("cj", "12");
    Map<String,  > map3 = new HashMap<String,  >();
    map3.put("name", "f");
    map3.put("cj", "31");
    list.add(map1);
    list.add(map3);
    list.add(map2);
    //排序前 
    for (Map<String,  > map : list) {
      System.out.println(map.get("cj"));
    }
    Collections.sort(list, new Comparator<Map<String,  >>() {
      public int compare(Map<String,  > o1, Map<String,  > 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,  > map : list) {
      System.out.println(map.get("cj"));
    }
  }
}