发布于2021-03-07 20:52 阅读(934) 评论(0) 点赞(14) 收藏(5)
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class sort {
public static void main(String[] args) {
List<Integer> list = new ArrayList<Integer>();
list.add(new Integer(5));
list.add(new Integer(13));
list.add(new Integer(4));
list.add(new Integer(9));
Collections.sort(list);
System.out.println(list.toString());
}
}
程序运行结果:
[4, 5, 9, 13],这种简单的排序直接按照自然顺序进行升序排列。
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class sort {
public static void main(String[] args) {
List<User> list = new ArrayList<User>();
list.add(new User("张三", 5));
list.add(new User("李四", 30));
list.add(new User("王五", 19));
list.add(new User("陈十七", 17));
Collections.sort(list); // 按年龄排序
System.out.println(list.toString());
}
}
class User implements Comparable<User>{
private String name; //姓名
private int age; // 年龄
public User(String name, int age) {
this.name = name;
this.age = age;
}
// getter && setter
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "User [name=" + name + ", age=" + age + "]";
}
@Override
public int compareTo(User user) { //重写Comparable接口的compareTo方法,
return this.age - user.getAge(); // 根据年龄升序排列,降序修改相减顺序即可
}
}
程序运行结果:根据年龄升序排列
[User [name=张三, age=5], User [name=陈十七, age=17], User [name=王五, age=19], User [name=李四, age=30]]
//对象中的数值类型排序
public class sort {
public static void main(String[] args) {
List<User> list = new ArrayList<User>();
list.add(new User("张三", 5));
list.add(new User("李四", 30));
list.add(new User("王五", 19));
list.add(new User("陈十七", 17));
Collections.sort(list, new Comparator<User>() {
@Override
public int compare(User u1, User u2) {
int diff = u1.getAge() - u2.getAge();
if (diff > 0) {
return 1;
}else if (diff < 0) {
return -1;
}
return 0; //相等为0
}
}); // 按年龄排序
System.out.println(list.toString());
}
}
运行结果:[User [name=张三, age=5], User [name=陈十七, age=17], User [name=王五, age=19], User [name=李四, age=30]]
//对象中的String类型排序
public class sort {
public static void main(String[] args) {
List<User> list = new ArrayList<User>();
list.add(new User("张三", 5));
list.add(new User("李四", 30));
list.add(new User("张三", 19));
list.add(new User("陈十七", 17));
Collections.sort(list, new Comparator<User>() {
@Override
public int compare(User u1, User u2) {
return u1.getName().compareTo(u2.getName());
}
}); // 按姓名排序
System.out.println(list.toString());
}
}
运行结果:[User [name=张三, age=5], User [name=张三, age=19], User [name=陈十七, age=17], User [name=李四, age=30]]
原文链接:https://blog.csdn.net/OOObject/article/details/114400025
作者:javabb
链接:http://www.javaheidong.com/blog/article/110807/5ecd6bd4e274908f3df0/
来源:java黑洞网
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