hashmap排序

hashMap会自动根据键来排序，但是有时我们想根据值来排序，那应该怎么做呢

答案就是用collections.sort（）方法.

import Other.person;

import java.util.*;

public class HashMapTest {

    public static void main(String[] args) {

      HashMap<String, person> map=new HashMap<String,person>();
      map.put("x",new person("aa",27));
      map.put("e",new person("ee",26));
      map.put("q",new person("cc",22));
      map.put("f",new person("bb",23));
      map.put("s",new person("ff",24));
      map.put("z",new person("dd",25));

      Set<Map.Entry<String,person>> mm=map.entrySet();

    ArrayList<Map.Entry<String,person>> arr=new ArrayList<Map.Entry<String,person>>(mm);

    Collections.sort(arr,new Comparator<Map.Entry<String,person>>() {
        @Override
        public int compare(Map.Entry<String,person> o1, Map.Entry<String,person> o2) {
            return (o1.getValue().getAge()+"").compareTo(o2.getValue().getAge()+"");
        }
    });

    for (Map.Entry<String,person> x:arr){
        System.out.println(x.getKey()+"  "+x.getValue().getName()+"  "+x.getValue().getAge());
    }
}
}

public class person {
    private String name;
    private int age;

    public person(String name,int age){
        this.name=name;
        this.age=age;
    }



    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }


}