使用Comparable接口自定义排序

Employee；

package textq;

/**

 * 调用接口Comparable排序

 * @author Administrator

 *

 */

public class Employee implements Comparable<Employee>{

private int id;

private String name;

private int age;

public Employee(int id,String name,int age){

    this.id=id;

    this.name=name;

    this.age=age;

}

@Override

//利用编号实现排序

public int compareTo(Employee o){

    if(id>o.id) return 1;

    else return -1;

}

@Override

public String toString(){

    StringBuilder sb=new StringBuilder();

    sb.append("员工编号"+id+",");

    sb.append("员工的名字"+name+",");

    sb.append("员工的年龄"+age);

    return sb.toString();

}

}

Test:

package textq;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

public class Test {

public static void main(String[] args) {

    List<Employee> list=new ArrayList<Employee>();

    list.add(new Employee(3,"java",21));

    list.add(new Employee(2,"java",22));

    list.add(new Employee(1,"java",23));

    System.out.println("排序前");

    for(Employee employee:list){

        System.out.println(employee);

    }

    System.out.println("排序后");

    Collections.sort(list);

    for(Employee employee:list){

        System.out.println(employee);

    }

}

}