2019独角兽企业重金招聘Python工程师标准>>>
package mianshi;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
/**
* @description
*
* @author shilvfei
*
* @date 2018年4月28日
*/
public class ArrayListTest {
public static void main(String[] args) {
User u1 = new User(1,"张三",23);
User u2 = new User(3,"李四",24);
User u3 = new User(2,"王五",29);
User u4 = new User(5,"赵流",21);
User u5 = new User(4,"黑八",22);
List<User> list = new ArrayList<>();
list.add(u1);
list.add(u2);
list.add(u3);
list.add(u4);
list.add(u5);
System.out.println("排序前:");
for (User user : list) {
System.out.println(user);
}
//Collections.sort(list, new SortByAge()); //按照年龄排序
Collections.sort(list,new SortByUserId());//按UserId排序
System.out.println("排序后:");
for (User user : list) {
System.out.println(user);
}
}
}
//年龄排序
class SortByAge implements Comparator<User>{
@Override
public int compare(User u1, User u2) {
if(u1.getAge()>u2.getAge()){
return 1;
}
return -1;
}
}
//UserId排序
class SortByUserId implements Comparator<User>{
@Override
public int compare(User u1, User u2) {
if(u1.getId()>u2.getId()){
return 1;
}
return -1;
}
}
//User实体
class User {
private int id ;
private String userName;
private int age;
public User(int id, String userName, int age) {
this.id = id;
this.userName = userName;
this.age = age;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User [id=" + id + ", userName=" + userName + ", age=" + age + "]";
}
}