java集合排序

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;

/*
 * Arrays.sort()
 * Connections.sort()
 *  这里 一个 .java 文件里面有两个 public 其中一个是 内部类
 */
public class Test2 {
    
    static int[] n = {6,5,8,9,4,2,3,7,0};
    static List<String> list = new ArrayList<String>();
    static List<A> list2 = new ArrayList<A>();
    
    
    public Test2(){
    }
    
    public static void main(String args[]){
        for(int i : n){
            list.add(i+"");
        }
        
        list2.add(new A(1,"a"));
        list2.add(new A(5,"f"));
        list2.add(new A(4,"e"));
        list2.add(new A(2,"b"));
        list2.add(new A(3,"d"));
        
        Arrays.sort(n);
        System.out.println(Arrays.toString(n));
        
        Collections.sort(list);
        System.out.println(list);
        
        Collections.sort(list2, new Comparator<A>() {

            @Override
            public int compare(A o1, A o2) {
                // TODO Auto-generated method stub
//                return o1.getName().compareTo(o2.getName());
                return o1.getId().compareTo(o2.getId());
            }
        });
        System.out.println(list2);
    }
    
    
    public static class A{
        private Integer id;
        private String name;
        
        public A(){}
        
        public A(int id, String name){
            this.id = id;
            this.name = name;
        }
        
        public Integer getId(){
            return this.id;
        }
        
        public void setId(Integer id){
            this.id = id;
        }
        
        public String getName(){
            return this.name;
        }
        
        public void setName(String name){
            this.name = name;
        }
        
        public String toString(){
            return "id : "+id+" name : "+name;
        }
    }
}

 控制台

[0, 2, 3, 4, 5, 6, 7, 8, 9]
[0, 2, 3, 4, 5, 6, 7, 8, 9]
[id : 1 name : a, id : 2 name : b, id : 3 name : d, id : 4 name : e, id : 5 name : f]