Java实现图书持久化

要求

构造图书类，包含名称（字符串）、作者（字符串）、出版社（字符串）、版本号（整数）、价格（浮点数），构造图书馆类，其中包含若干图书，用容器存储图书对象，然后定义方法void addBook(Book b)添加图书对象，定义方法void persist()，将所有图书存至本地文件books.dat里，定义方法Book[] restore() 从文件books,dat中读取所有图书，并返回图书列表数组。 main函数中构造图书馆类对象，向其中添加3个图书对象，测试其persist和restore方法。（注意，请使用对象序列化方法实现）

代码

复制代码

import java.io.*;
import java.util.*;




class Book {
    String name;
    String author;
    String press;
    int no;
    double price;

    public Book(String _name, String _author, String _press, int _no, double _price) {
        this.name = _name;
        this.author = _author;
        this.press = _press;
        this.no = _no;
        this.price = _price;
    } 

    public String toString() {
        return name+" "+author+" "+press +" "+no+" "+price;
    } 
}


class Library{
    Book[] books=new Book[99999999];
    int nums=0;

    public void addBook(Book book) {
        books[nums]=book;
        nums++;
    }

    public void persist() throws IOException {
        File file=new File("./books.dat");
        if(!file.exists()){
            file.createNewFile();
        }
        FileWriter fw=new FileWriter(file);
        for(int i=0;i<nums;i++){
            fw.write(books[i].toString());
            fw.write("\n");
        }
        fw.flush();
        fw.close();
    }

    public Book[] restore() throws IOException {
        Library library = new Library();
        File file=new File("./books.dat");
        if(!file.exists()) {
            file.createNewFile();
        }
        BufferedReader input=null;
        input=new BufferedReader(new InputStreamReader(new FileInputStream("./books.dat")));
        String s=input.readLine();
        while(s!=null){
            String[] s1=s.split(" ");
            Book book=new Book(s1[0],s1[1],s1[2],Integer.parseInt(s1[3]),Double.parseDouble(s1[4]));
            library.addBook(book);
            s=input.readLine(); 
        }
        input.close();
        return library.books;
    }
}


public class Main5 {
    public static void main(String[] args) throws IOException  {
        Library library = new Library();
        library.addBook(new Book("大秦帝国1", "czk", "百花出版社", 10001, 38.88));
        library.addBook(new Book("大秦帝国2", "czk", "百花出版社", 10002, 38.88));
        library.addBook(new Book("大秦帝国3", "czk", "百花出版社", 10003, 38.88));
        library.persist();
        Book books[] = library.restore();
        for(int i=0;i<library.nums;i++){
            System.out.println(books[i].toString());
        }
    }
}

分析

没什么想说的，水一水