使用到的是:
Collections.sort();
用法是:
List<Book> list_book = new ArrayList<Book>();
Book book=new Book(1,"aa","a",2,1);
Book book1=new Book(2,"bb","b",2,1);
Book book2=new Book(3,"cc","c",2,1);
list_book.add(book2);
list_book.add(book1);
list_book.add(book);
Collections.sort(list_book);
for (Book book3 : list_book) {
System.out.println(book3);
}
Book類要實作:Comparable接口 重寫compareTo()方法
package com.springboot_thread.bean;
import lombok.Data;
import lombok.Getter;
import lombok.Setter;
/**
* 作用:
*/
@Data
public class Book implements Comparable<Book>{
private Integer id;
private String bookName;
private String author;
private Integer stock;
private Integer tId;
public Book() {
}
public Book(Integer id, String bookName, String author, Integer stock, Integer tId) {
this.id = id;
this.bookName = bookName;
this.author = author;
this.stock = stock;
this.tId = tId;
}
@Override
public int compareTo(Book o) {
return this.id-o.id; //升序
//return o.id-this.id; 降序
}
}
轉載于:https://www.cnblogs.com/bulrush/p/10747613.html