目录
概要
JavaWeb开发案例，使用JSP、Servlet、JDBC原生框架技术，实现用户模块的功能开发，主要用于学习。
功能
1. 注册
2. 登录
3. 用户模块
3.1 查询用户信息
3.2 删除用户信息
3.3 修改用户信息
技术名词解释
JSP：全称Java Server Pages, 是由Sun公司主导创建的一种动态网页技术标准，JSP中可以编写Java脚本
Servlet: 是Java Servlet的简称，称为小服务程序或服务连接器，用Java编写的服务器端程序,用来接收和响应来自web客户端发送的请求
JDBC：Java数据库连接，（Java Database Connectivity，简称JDBC）是Java语言中用来规范程序如何来访问数据库的应用程序接口
技术细节
1. 项目列表
2. 网页
res.html 注册页面
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>用户注册</h1>
<form action="res" method="post">
<input type="text" name="username"><br><br>
<input type="password" name="password"><br><br>
<button type="submit">注册</button>
</form>
</body>
</html>
login.html 登录页面
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>用户登录</h1>
<form action="login" method="post">
<input type="text" name="username"><br><br>
<input type="password" name="password"><br><br>
<button type="submit">登录</button>
</form>
</body>
</html>
main.jsp 首页
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!-- 引入list包 -->
<%@ page import="java.util.List"%>
<!-- 引入user包 -->
<%@ page import="com.qls.bean.User"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>XXX官网</h1>
<!-- 编写Java代码，从当前请求中获取到用户信息 -->
<p>
欢迎你,
<%=request.getParameter("username") %>
</p>
<!-- 编写Java代码，获取请求对象中存储的list集合 -->
<%
List<User> list = (List)request.getAttribute("list");
%>
<table>
<thead>
<tr>
<th>序号</th>
<th>账号</th>
<th>密码</th>
<th>操作</th>
</tr>
</thead>
<tbody>
<%for(User user : list){ %>
<tr>
<td><%=user.getId()%></td>
<td><%=user.getUsername()%></td>
<td><%=user.getPassword()%></td>
<td><a href="deleteUser?id=<%=user.getId()%>">删除</a></td>
</tr>
<%}%>
</tbody>
</table>
</body>
</html>3. Servlet
DBUtils工具类，建立数据库连接
package com.qls.utils;
import java.sql.Connection;
import java.sql.DriverManager;
public class DBUtils {
String url = "jdbc:mysql://localhost:3306/user";
String user = "root";
String pword = "root";
static {
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public Connection getConn() throws Exception {
Connection con = DriverManager.getConnection(url, user, pword);
return con;
}
}
User类，创建JavaBean
package com.qls.bean;
/**
* 用户类，存储用户表中的数据
* 属性与用户表的字段保持一致
* */
public class User {
int id;
String username;
String password;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
ResServlet 注册功能
package com.qls.servlet;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.qls.utils.DBUtils;
/**
* 注册请求
* */
@WebServlet("/res")
public class ResServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//接受请求
String username = request.getParameter("username");
String password = request.getParameter("password");
//获得链接
DBUtils db = new DBUtils();
try {
Connection conn = db.getConn();
String sql = "insert into user(username,password) values(?,?)";
PreparedStatement ps = conn.prepareStatement(sql);
//设置sql语句的参数
ps.setString(1, username);
ps.setString(2, password);
//执行sql 得到执行结果
int i = ps.executeUpdate();
//处理结果
if(i > 0) {
//执行成功，重定向跳转到登录页面
response.sendRedirect("login.html");
}else {
//执行失败 重定向跳转到注册页面
response.sendRedirect("res.html");
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
LoginSertvlet 登录功能
package com.qls.servlet;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.qls.utils.DBUtils;
/**
* 登录请求
*/
@WebServlet("/login")
public class LoginServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
DBUtils db = new DBUtils();
try {
Connection conn = db.getConn();
String sql = "select username,password from user where username=? and password=?";
//预处理对象
PreparedStatement ps = conn.prepareStatement(sql);
//给sql语句中的?占位符赋值
ps.setString(1, username);
ps.setString(2, password);
//执行sql，获取结果集
ResultSet rs = ps.executeQuery();
//处理结果集
while(rs.next()) {
String uname = rs.getString("username");
String pword = rs.getString("password");
//判断结果
if(username.equals(uname) && password.equals(pword)) {
//请求转发 跳转到主页
request.getRequestDispatcher("/show").forward(request, response);
}else {
//重定向，跳转到登录页面
response.sendRedirect("login.html");
}
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
ShowAllServlet 用户模块，查询用户信息功能
package com.qls.servlet;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.qls.bean.User;
import com.qls.utils.DBUtils;
/**
* 查询用户功能
*/
@WebServlet("/show")
public class ShowAllServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
DBUtils db = new DBUtils();
try {
Connection conn = db.getConn();
String sql = "select * from user";
PreparedStatement ps = conn.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
//创建集合，保存user对象
List<User> list = new ArrayList<User>();//user user
while(rs.next()) { //2 root root
int id = rs.getInt("id");//2
String username = rs.getString("username");//root
String password = rs.getString("password");//root
//创建User类对象 将遍历出来的一条数据，保存到user对象的属性中
User user = new User();
user.setId(id);
user.setUsername(username);
user.setPassword(password);
//将user对象 添加到list集合中
list.add(user);
}
//将list集合保存到request对象中
request.setAttribute("list", list);
//请求转发
request.getRequestDispatcher("main.jsp").forward(request, response);
}catch (Exception e) {
// TODO: handle exception
}
}
}
DeleteUserServlet 用户模块，删除用户信息功能
package com.qls.servlet;
import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.qls.bean.User;
import com.qls.utils.DBUtils;
/**
* 删除用户功能
*/
@WebServlet("/deleteUser")
public class DeleteUserServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
int uid = Integer.parseInt(id);
DBUtils db = new DBUtils();
try {
Connection conn = db.getConn();
String sql = "delete from user where id=?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1, uid);
int i = ps.executeUpdate();
if(i > 0) {
//请求转发 删除成功，将请求转发到查询表用户的servlet中，重新查询用户，重新展示用户信息
request.getRequestDispatcher("/show").forward(request, response);
}else {
//请求转发
request.getRequestDispatcher("main.jsp").forward(request, response);
}
}catch (Exception e) {
// TODO: handle exception
}
}
}
小结
本文主要使用JavaWeb原生框架，完成一个简单的学习案例，提供增删改查方法。
JSP中使用Java代码获取数据、展示数据。
Servlet中接收请求、处理业务逻辑、资源跳转。
JDBC建立数据库连接。