Java对List的排序

Java中对List排序的实现

一.实例

1.方法1：实现Comparable接口

import grammar.TestIntValue;

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

public class JavaTest {

    public static int initValue = 8;
    public static void main(String[] args) {
        Student s3 = new Student(3, "hadoop");
        Student s1 = new Student(1, "java");
        Student s2 = new Student(2, "spark");
        List students = new ArrayList();
        students.add(s3);
        students.add(s1);
        students.add(s2);
        System.out.println("Before:");
        for(Student s : students){
            System.out.println(s.toString());
        }
        Collections.sort(students);
        System.out.println("After:");
        for(Student s : students){
            System.out.println(s.toString());
        }
    }

   static class Student implements Comparable{
        private int id;
        private String name;

        public Student(int id ,String name){
            this.id = id;
            this.name = name;
        }

        @Override
        public int compareTo(Student stu) {
            return this.id - stu.id;
        }

       @Override
       public String toString() {
            return "id: "+this.id+",name: "+this.name;
       }
   }
}

• 实现结果

Before:
id: 3,name: hadoop
id: 1,name: java
id: 2,name: spark
After:
id: 1,name: java
id: 2,name: spark
id: 3,name: hadoop

2.匿名内部类