此代码只考虑正确情况，未判断错误情况

package dboperate;

import java.util.Scanner;

import model.BookDB;

import dboperate.ConnectionMC;

public class MainClassDB {

public MainClassDB()

{

Scanner scanner = new Scanner(System.in);

while(true)

{

System.out.println("欢迎进入图书管理系统！");

System.out.println("添加新书————————————1");

System.out.println("删除图书————————————2");

System.out.println("修改图书————————————3");

System.out.println("查询图书————————————4");

System.out.println("退出系统————————————5");

int chioce = scanner.nextInt();

if(chioce == 5)

{

System.out.println("系统退出了！");

break;

}

switch(chioce)

{

case 1 : addBook();

break;

case 2 : deleteBook();

break;

case 3 : updateBook();

break;

case 4 : printAllBook();

break;

}

}

}

public void addBook()

{

Scanner scanner = new Scanner(System.in);

System.out.println("请输入需要添加的书名：");

String bookname = scanner.nextLine();

System.out.println("请输入需要添加的图书ID：");

String id = scanner.nextLine();

System.out.println("请输入需要添加的图书价格：");

Double price = scanner.nextDouble();

System.out.println("请输入需要添加的图书作者：");

String writer = scanner.next();

BookDB book = new BookDB(bookname,id,price,writer);

ConnectionMC connectionmc = new ConnectionMC();

connectionmc.addBook(book);

connectionmc.printAllBook();

}

public void deleteBook()

{

Scanner scanner = new Scanner(System.in);

System.out.println("请输入你要删除的书名");

String bookName = scanner.nextLine();

ConnectionMC connectionmc = new ConnectionMC();

connectionmc.deleteBook(bookName);

connectionmc.printAllBook();

}

public void updateBook()

{

System.out.println("请输入你要修改的书名");

Scanner scanner = new Scanner(System.in);

String oldBookName = scanner.nextLine();

ConnectionMC connectionmc = new ConnectionMC();

System.out.println("请输入新书名：");

String newBookName = scanner.nextLine();

System.out.println("请输入新ID：");

String newId = scanner.nextLine();

System.out.println("请输入新价格：");

double newprice = scanner.nextDouble();

System.out.println("请输入新书作者：");

String newwriter = scanner.next();

BookDB newbook = new BookDB(newBookName,newId,newprice,newwriter);

connectionmc.updateBook(oldBookName,newbook);

System.out.println("修改成功！");

connectionmc.printAllBook();

}

public void printAllBook()

{

ConnectionMC connectionmc = new ConnectionMC();

connectionmc.printAllBook();

}

public static void main(String agrs[])

{

new MainClassDB();

}

}

package dboperate;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import model.BookDB;

public class ConnectionMC {

static final String url = "jdbc:mysql://localhost:3306/booklist?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8";

static final String name = "com.mysql.cj.jdbc.Driver";

static final String user = "root";

static final String password = "13060228428";

static //静态代码段会在类被加载时自动执行一次

{

try

{

Class.forName(name);

System.out.println("链接成功！");

}

catch(ClassNotFoundException cE)

{

System.out.println("Class Not Found Exception:"+cE.toString());

}

}

public static Connection getConnection()

{

try {

return DriverManager.getConnection(url, user, password);

} catch (SQLException e) {

e.printStackTrace();

return null;

}

}

public static void closeConnection(ResultSet rs,Statement statement,Connection conn)

{

try {

if(rs!=null)rs.close();

if(statement!=null)statement.close();

if(conn!=null)conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

}

public static void closeConnection(Statement statement,Connection conn)

{

closeConnection(null,statement,conn);

}

public void addBook(BookDB book)

{

Connection conn = ConnectionMC.getConnection();

String sql = "insert into booklist(bookname,id,price,writer) values(?,?,?,?)";

PreparedStatement psmt;

try {

psmt = conn.prepareStatement(sql);

psmt.setString(1, BookDB.getBookName());

psmt.setString(2, BookDB.getId());

psmt.setDouble(3, BookDB.getPrice());

psmt.setString(4, BookDB.getwriter());

psmt.execute();

ConnectionMC.closeConnection(psmt, conn);

} catch (SQLException e1) {

e1.printStackTrace();

}

}

public void updateBook(String oldBookName,BookDB newbook)

{

Connection conn = ConnectionMC.getConnection();

String sql ="UPDATE booklist SET bookname='"+BookDB.getBookName()+"',id='"+BookDB.getId()+

"',price='"+BookDB.getPrice()+"',writer='"+BookDB.getwriter()+"'WHERE bookname='"+oldBookName+"'";

PreparedStatement psmt=null;

try {

psmt = conn.prepareStatement(sql);

psmt.executeUpdate(sql);

ConnectionMC.closeConnection(psmt, conn);

} catch (SQLException e) {

e.printStackTrace();

}

}

public void deleteBook(String bookName)

{

Connection conn = ConnectionMC.getConnection();

String sql = "delete from booklist where bookName=?";

try {

PreparedStatement psmt = conn.prepareStatement(sql);

psmt.setString(1,bookName);

psmt.execute();

ConnectionMC.closeConnection(psmt, conn);

} catch (SQLException e) {

e.printStackTrace();

}

}

public void printAllBook()

{

try

{

Connection conn = ConnectionMC.getConnection();

Statement s = conn.createStatement();

String sql = "select * from booklist";

ResultSet rs = s.executeQuery(sql);

while (rs.next())

{

String bookname = rs.getString(1);

String id = rs.getString(2);

Double price = rs.getDouble(3);

String writer = rs.getString(4);

System.out.println("bookname:" + bookname + ", id:" + id + ", price:" + price+", wirter:"+ writer);

}

ConnectionMC.closeConnection(rs, s, conn);

} catch (SQLException e) {

e.printStackTrace();

}

}

public static void main(String[] args) {

// TODO Auto-generated method stub

}

}

package model;

public class BookDB {

private static String bookName;

private static String id;

private static String writer;

private static Double price;

public BookDB(String bookName,String id,Double price,String writer)

{

BookDB.bookName = bookName;

BookDB.id = id;

BookDB.price = price;

BookDB.writer = writer;

}

public static String getId()

{

return id;

}

public void setId(String id)

{

BookDB.id = id;

}

public static String getBookName()

{

return bookName;

}

public void setBookName(String bookName)

{

BookDB.bookName = bookName;

}

public static Double getPrice()

{

return price;

}

public void setPrice(Double price)

{

BookDB.price = price;

}

public void setwriter(String writer)

{

BookDB.writer=writer;

}

public static String getwriter()

{

return writer;

}

public String toString()

{

return(bookName+","+id+","+price+","+writer);

}

}