项目结构
Book.java
package beans;
public class Book {private Integer id;private String name;private double price;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public double getPrice() {return price;}public void setPrice(double price) {this.price = price;}
}BookDao.java
package dao;import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;import javax.resource.cci.ResultSet;import beans.Book;public class BookDao {
@SuppressWarnings({ "rawtypes", "unchecked" })
public ArrayList queryBookById(String id) {Connection conn=null;ArrayList books=new ArrayList();
try {try {Class.forName("com.mysql.jdbc.Driver");} catch (ClassNotFoundException e) {e.printStackTrace();}@SuppressWarnings("unused")String url="jdbc:mysql://localhost:3306/books?useUnicode=true&charaterEncoding=UTF-8";conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/books","root","123456");String sql="select * from book where id=?";PreparedStatement ps=conn.prepareStatement(sql);ps.setString(1, id);ResultSet rs=(ResultSet) ps.executeQuery();while(rs.next()){Book book=new Book();book.setId(rs.getInt(1));book.setName(rs.getString(2));book.setPrice(rs.getDouble(3));books.add(book);}rs.close();ps.close();} catch (SQLException e) {e.printStackTrace();}finally {try{if(conn!=null){conn.close();conn=null;}}catch(Exception e){}}return books;
}
}BookServlet.java
package servlet;import java.io.IOException;
import java.util.ArrayList;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import dao.BookDao;@SuppressWarnings("serial")
public class BookServlet extends HttpServlet {@SuppressWarnings("rawtypes")public void servlet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {String id =request.getParameter("id");BookDao dao=new BookDao();ArrayList books=dao.queryBookById(id);request.setAttribute("books", books);ServletContext application =this.getServletContext();RequestDispatcher rd=application.getRequestDispatcher("/showbook.jsp");rd.forward(request, response); }}
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<html>
<head> <title>查询书籍系统</title>
</head>
<body><form action="servlet/BookServlet" method="post">
请输入id: <input type="text" name="id"><input type="submit" value="查询"></form></body>
</html>showBook.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page import="dao.BookDao" %>
<%@ page import="java.util.ArrayList" %>
<%@ page import="beans.Book" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>书籍信息</title>
</head>
<body>
<%ArrayList books=(ArrayList)request.getAttribute("books");
%>
<table border="2">
<tr>
<td>id</td>
<td>name</td>
<td>price</td>
</tr>
<%
for (int i = 0;i < books.size();i++)
{
Book book = (Book)books.get(i);
%>
<tr>
<td><%=book.getId()%></td>
<td><%=book.getName()%></td>
<td><%=book.getPrice()%></td>
</tr>
<%
}
%>
</table>
</body>
</html>books.sql
/*Navicat Premium Data TransferSource Server : 11Source Server Type : MySQLSource Server Version : 80030Source Host : localhost:3306Source Schema : booksTarget Server Type : MySQLTarget Server Version : 80030File Encoding : 65001Date: 05/12/2023 21:02:10
*/SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;-- ----------------------------
-- Table structure for book
-- ----------------------------
DROP TABLE IF EXISTS `book`;
CREATE TABLE `book` (`id` int NOT NULL,`name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL,`price` double NULL DEFAULT NULL,PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;-- ----------------------------
-- Records of book
-- ----------------------------
INSERT INTO `book` VALUES (1, '西游记', 100);SET FOREIGN_KEY_CHECKS = 1;
mysql.jar包下载
MySQLjar包官方版下载丨最新版下载丨绿色版下载丨APP下载-123云盘
--更新于12-6
本文仅仅用了测试，会出现报错！！！
如报错HTTP method POST is not supported by this URL
或者The type java.lang.CharSequence cannot be resolved. It is indirectly referenced from required .class files等
经过一晚上测试，发现是由于自己book.java文件使用私有属性，以及在getid方法中出现于bookdao.java的类型并不匹配，加上EE5的library的导入，最后完成调试！
下面是改后的结构
数据库
数据导入用的是MySQL的workbench，可复制下来，直接在workbench中运行即可
-- MySQL dump 10.13 Distrib 8.0.32, for Win64 (x86_64)
--
-- Host: localhost Database: book
-- ------------------------------------------------------
-- Server version 8.0.32/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!50503 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;--
-- Table structure for table `book`
--DROP TABLE IF EXISTS `book`;
/*!40101 SET @saved_cs_client = @@character_set_client */;
/*!50503 SET character_set_client = utf8mb4 */;
CREATE TABLE `book` (`id` varchar(45) NOT NULL,`name` varchar(45) DEFAULT NULL,`price` float DEFAULT NULL,PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
/*!40101 SET character_set_client = @saved_cs_client */;--
-- Dumping data for table `book`
--LOCK TABLES `book` WRITE;
/*!40000 ALTER TABLE `book` DISABLE KEYS */;
INSERT INTO `book` VALUES ('1','水浒传',88.8);
/*!40000 ALTER TABLE `book` ENABLE KEYS */;
UNLOCK TABLES;
/*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;/*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
/*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
/*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
/*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;-- Dump completed on 2023-12-06 1:54:04
数据库数据完成后，进行book.java的修改
package beans;public class Book {String id;String name;float price;public String getId() {return id;}public void setId(String id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public float getPrice() {return price;}public void setPrice(float price) {this.price = price;}
}重启tomcat6.0
最后成功
在今晚test时候发现的问题
注意变量的类型，也可以继续使用id int ，price double型
重新生成方法
select all 选择public，生成
代码
package beans;public class Book {int id;String name;double price;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public double getPrice() {return price;}public void setPrice(double price) {this.price = price;}}修改bookdao.java
重启后访问报错
HTTP Status 500 - javax.servlet.ServletException: java.lang.NoSuchMethodError: beans.Book.getId()Ljava/lang/String;
（有待解决）
没有该方法调用
