Java Collections.sort方法对list集合排序

1、排序测试类

package com.web.test;

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

public class UserSort {

public static void main(String[] args) {
        List<User> userList =new ArrayList<User>();
        userList.add(new User(1,2.2));
        userList.add(new User(2,1.1));
        userList.add(new User(3,4.4));
        userList.add(new User(4,5.5));
        userList.add(new User(5,3.3));

        Collections.sort(userList, new Comparator<User>() {
public int compare(User u1, User u2) {
return new Double(u1.getSalary()).compareTo(new Double(u2.getSalary())); //升序
// return new Double(u2.getSalary()).compareTo(new Double(u2.getSalary())); //降序
            }
        });

for(User user : userList){
            System.out.println(user);
        }
    }
}

2、User对象，存储javabean属性

package com.web.test;

import java.io.Serializable;

/**
 * 用户
 *
 * @author Web
 */
public class User implements Serializable{
private static final long serialVersionUID = 1L;

private long id; // 主键
private double salary; // 薪资

public User() {

    }

public User(long id, double salary) {
super();
this.id = id;
this.salary = salary;
    }

public long getId() {
return id;
    }

public void setId(long id) {
this.id = id;
    }

public double getSalary() {
return salary;
    }

public void setSalary(double salary) {
this.salary = salary;
    }

@Override
public String toString() {
return "User [id=" + id + ", salary=" + salary + "]";
    }

}