List集合中如何对对象进行排序呢?

List集合排序的实现思路

1.对象实体类需集成 Comparable 接口
   并实现 compareTo 方法
2.使用 Collections.sort(); 
   方法即可对list集合进行排序操作

 List<Book> list_book = new ArrayList<Book>();
        Book book=new Book(1,"java","a",8,2);
        Book book1=new Book(2,"jj","b",9,3);
        Book book2=new Book(3,"ttt","c",10,4);
        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);
        }
 
package com.java265.bean;

import lombok.Data;
import lombok.Getter;
import lombok.Setter;
 
@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
    }
}