Jsp+Servlet+JDBC(c3p0连接池)+Mysql实现增删改查
一、 项目介绍
1、采用MVC架构模式中，JSP充当视图（view）而Servlet适合充当控制器（controller）。
2、项目开发工具：
(1) jdk1.8.0_92
(2) apache-tomcat-8.5.39
(3) mysql-5.5.45-winx64
(4) Navicat_for_MySQL_11.0.10
(5) IDEA-2019.3.4
3、所需jar包：
(1) c3p0-0.9.1.2.jar
(2) jstl-1.2.jar
(3) mysql-connector-java-5.1.6.jar
4、项目目录结构
5、数据库信息
6、项目截图(只展示部分功能截图)
二、源码
1、c3p0-config.xml （此配置文件直接是在src文件夹下）
<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
<!-- 我们希望在配置文件中，出现链接的参数信息 -->
<!-- 1、配置默认数据源-->
<default-config>
<!-- name 属性定义 链接参数的key 标签的内容 代表值-->
<property name="driverClass">com.mysql.jdbc.Driver</property>
<!-- 采用了简写形式，三个/-->
<property name="jdbcUrl">jdbc:mysql:///myschool
<property name="user">root</property>
<property name="password">root</property>
</default-config>
</c3p0-config>
注意：MySQL 8.0 以上版本 数据库驱动发送变化，配置文件使用下面的
<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
<!-- 我们希望在配置文件中，出现链接的参数信息 -->
<!-- 1、配置默认数据源-->
<default-config>
<!-- name 属性定义 链接参数的key 标签的内容 代表值-->
<property name="driverClass">com.mysql.cj.jdbc.Driver</property>
<!-- 采用了简写形式，三个/-->
<property name="jdbcUrl">jdbc:mysql:///myschool?characterEncoding=utf8&useUnicode=true&useSSL=false&serverTimezone=UTC
<property name="user">root</property>
<property name="password">root</property>
</default-config>
</c3p0-config>
2、Jsp页面
(1) index.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
Created by IntelliJ IDEA.
User: 南一
Date: 2020/9/8
Time: 22:31
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>显示所有用户信息</title>
<%
String path = request.getContextPath();
%>
<style type="text/css">
a {
text-decoration: none;
border: 1px solid red;
}
table {
border: 1px solid black;
text-align: center;
border-collapse: collapse;
}
tr, td {
border: 1px solid black;
}
</style>
</head>
<body bgcolor="#ffe4c4">
<div align="center">
<h3>员工明细列表</h3>
<table>
<tr>
<td>序号</td>
<td>员工编号</td>
<td>员工姓名</td>
<td>password</td>
<td>update</td>
<td>delete</td>
</tr>
<%
int i = 1;
pageContext.setAttribute("index", i);
%>
<c:forEach items="${requestScope.lists}" var="list">
<tr>
<td>${index}</td>
<td>${list.id}</td>
<td>${list.username}</td>
<td>${list.password}</td>
<td>
<button onclick=" location.href='UpdateUserServlet?id=${list.id}'">修改</button>
</td>
<%-- 直接通过<a>超链接标签访问DeleteUserServlet，onclick="return confirm('确定删除吗？')浏览器弹窗提醒--%>
<td><a href="DeleteUserServlet?id=${list.id}" onclick="return confirm('确定删除吗？')">删除</a></td>
</tr>
<%
i++;
pageContext.setAttribute("index", i);
%>
</c:forEach>
</table>
<br>
<a href="/ShowUserServlet">显示所有</a>
<a href="add.jsp">添加</a>
<a href="/DeleteAllUserServlet">删除所有</a>
</div>
</body>
</html>
(2) add.jsp
<%--
Created by IntelliJ IDEA.
User: 南一
Date: 2020/9/8
Time: 23:56
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>添加</title>
<style type="text/css">
a {
text-decoration: none;
border:1px solid red;
}
</style>
<script type="text/javascript">
function UserBlur() {
//根据id拿到用户输入的输入框
var _input = document.getElementById("username");
//获取输入框的内容
var _username = _input.value;
//创建regExp对象
var regExp = new RegExp("^[a-zA-Z\u4e00-\u9fa5]+$");
//判断用户输入的名字是不是符合我们的校验规则
if (regExp.test(_username)) {
var _input = document.getElementById("UserSpan");
_input.innerHTML = "";
} else {
var _input = document.getElementById("UserSpan");
_input.innerHTML = "必须是字母汉字";
}
}
</script>
</head>
<body bgcolor="#7fffd4">
<h4 align="">添加页面</h4>
<%--${pageContext.request.contextPath}获取项目名字--%>
<form method="post" action="/AddUserServlet">
用户名：
<input type="text" name="username" id="username" onblur="UserBlur();"/><font color="red">*</font>
<font color="red"><span id="UserSpan"></span></font><br>
密 码：<input type="password" name="password"/><font color="red">${requestScope.p}</font><br>
<br>
<input type="submit" value="添加"/>
<input type="reset" value="重置"/>
<a href="http://localhost:8080/ShowUserServlet">返回</a>
</form>
</body>
</html>
(3) update.jsp
<%--
Created by IntelliJ IDEA.
User: 南一
Date: 2020/9/9
Time: 21:03
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>修改页面</title>
<style type="text/css">
a {
text-decoration: none;
border: 1px solid red;
}
</style>
</head>
<body>
<%-- 获取路径--%>
<form action="/FinalUpdateServlet" method="get">
用户id:<input type="text" name="id" id="id" value="${map.id}" readonly="readonly"/>
<font color="red">用户id不允许修改</font><br>
用户名：
<input type="text" name="username" id="username" value="${map.username}"/><br>
密 码：<input type="password" name="password" id="password" value="${map.password}"/><br>
<input type="submit" value="修改"/>
<a href="http://localhost:8080/ShowUserServlet">返回</a>
</form>
</body>
</html>
3、utils工具类
JdbcUtil.java
package com.utils;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class JdbcUtil {
//创建c3p0的实例，读取src下面的配置文件中default-config里面的默认数据源
private static ComboPooledDataSource ds = new ComboPooledDataSource();
//创建c3p0的实例，读取src下面的配置文件中named-config里面的初始数据源
// private static ComboPooledDataSource ds1 = new ComboPooledDataSource("petshop");
//从连接池里面获取连接
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
//关闭两个参数，释放资源
public static void close(Connection conn, PreparedStatement ps) {
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
//使用连接池后，此时的close()并不是关闭链接，而是把链接放回到了连接池中
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
//关闭三个参数，释放资源
public static void close(Connection conn, PreparedStatement ps, ResultSet rs) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
ps.close();
} catch (SQLException e) {
e.printStackTrace();
}
try {
//使用连接池后，此时的close()并不是关闭链接，而是把链接放回到了连接池中
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
4、pojo层（实体映射层）
User.java
package com.pojo;
public class User {
private int id;
private String username;
private 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;
}
public User() {
}
public User(int id, String username, String password) {
this.id = id;
this.username = username;
this.password = password;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}
5、dao层（直接与数据库进行交互的层）,这里我将显示所有、增加、删除、修改的方法写在了一个java文件里
ShowUserDaoImpl.java
package com.dao;
import com.pojo.User;
import com.utils.JdbcUtil;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class ShowUserDaoImpl {
//显示所有
public List<User> showUser() {
//创建连接变量，并且赋初始值为null
Connection conn = null;
PreparedStatement pstm = null;
ResultSet rs = null;
//定义list集合存对象信息
List<User> list = new ArrayList<>();
try {
conn = JdbcUtil.getConnection();
String sql = "select * from user";
pstm = conn.prepareStatement(sql);
rs = pstm.executeQuery();
while (rs.next()) {
//获取数据库的信息
int id = rs.getInt("id");
String username = rs.getString("username");
String password = rs.getString("password");
//把查询到的信息封装到user对象中
User resUser = new User();
resUser.setId(id);
resUser.setUsername(username);
resUser.setPassword(password);
//把user对象添加到list集合中
list.add(resUser);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.close(conn, pstm, rs);
}
return list;
}
//添加用户信息
public int addDaoUser(User user) {
//创建连接变量，并且赋初始值为null
Connection conn = null;
PreparedStatement pstm = null;
try {
conn = JdbcUtil.getConnection();
//因为id在MySQL中设置的是自动增长，所以赋值里面填null即可
String sql = "insert into user(id,username,password) value (null,?,?) ";
pstm = conn.prepareStatement(sql);
pstm.setString(1, user.getUsername());
pstm.setString(2, user.getPassword());
int i = pstm.executeUpdate();
if (i > 0) {
return 1;
} else {
return 0;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.close(conn, pstm);
}
return 0;
}
//删除用户
public int deleteDaoUser(String id) {
//创建连接变量，并且赋初始值为null
Connection conn = null;
PreparedStatement pstm = null;
try {
conn = JdbcUtil.getConnection();
//因为id在MySQL中设置的是自动增长，所以赋值里面填null即可
String sql = "delete from user where id = ?";
pstm = conn.prepareStatement(sql);
pstm.setString(1, id);
int i = pstm.executeUpdate();
if (i > 0) {
return 1;
} else {
return 0;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.close(conn, pstm);
}
return 0;
}
//删除所有用户信息
public int deleteAllDaoUser() {
//创建连接变量，并且赋初始值为null
Connection conn = null;
PreparedStatement pstm = null;
try {
conn = JdbcUtil.getConnection();
//因为id在MySQL中设置的是自动增长，所以赋值里面填null即可
String sql = "delete from user";
pstm = conn.prepareStatement(sql);
int i = pstm.executeUpdate();
if (i > 0) {
return 1;
} else {
return 0;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.close(conn, pstm);
}
return 0;
}
//先根据id去查询，用作回显
public Map<String, Object> toUpdateDaoUser(int id) {
//创建连接变量，并且赋初始值为null
Connection conn = null;
PreparedStatement pstm = null;
ResultSet rs = null;
//定义Map集合存对象信息
Map<String, Object> map = new HashMap<String, Object>();
try {
conn = JdbcUtil.getConnection();
String sql = "select * from user where id = ?";
pstm = conn.prepareStatement(sql);
pstm.setInt(1, id);
System.out.println(sql);
rs = pstm.executeQuery();
while (rs.next()) {
//获取数据库的信息
int userid = rs.getInt("id");
String username = rs.getString("username");
String password = rs.getString("password");
//放到Map集合
map.put("id", userid);
map.put("username", username);
map.put("password", password);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.close(conn, pstm, rs);
}
return map;
}
//最终修改
public boolean updateUser(User user) {
//创建连接变量，并且赋初始值为null
Connection conn = null;
PreparedStatement pstm = null;
try {
conn = JdbcUtil.getConnection();
String sql = "update user set username = ?,password = ? where id = ?";
pstm = conn.prepareStatement(sql);
pstm.setString(1, user.getUsername());
pstm.setString(2, user.getPassword());
pstm.setInt(3, user.getId());
int a = pstm.executeUpdate();
if (a > 0) {
return true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcUtil.close(conn, pstm);
}
return false;
}
}
6、service层（业务处理层），调用dao层方法
ServiceImpl.java
package com.service;
import com.dao.ShowUserDaoImpl;
import com.pojo.User;
import java.util.List;
import java.util.Map;
public class ServiceImpl {
//注入dao层
ShowUserDaoImpl addDao = new ShowUserDaoImpl();
//显示所有用户信息
public List<User> showAllUser() {
return addDao.showUser();
}
//添加用户
public int addUser(User user) {
return addDao.addDaoUser(user);
}
//删除用户
public int deleteUser(String id) {
return addDao.deleteDaoUser(id);
}
//删除所有用户
public int deleteAllUser() {
return addDao.deleteAllDaoUser();
}
//修改之前先查询，进行回显
public Map<String, Object> toUpdate(int id) {
return addDao.toUpdateDaoUser(id);
}
//最终修改
public boolean updateUser(User user) {
boolean updateUser = addDao.updateUser(user);
if (updateUser == true) {
return updateUser;
}
return false;
}
}
7、servlet层（请求控制层）
ShowUserServlet.java
package com.controller;
import com.pojo.User;
import com.service.ServiceImpl;
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 java.io.IOException;
import java.util.List;
@WebServlet("/ShowUserServlet")
public class ShowUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//注入service层
ServiceImpl service = new ServiceImpl();
//调用service层方法
List<User> list = service.showAllUser();
//把获取到的list集合查询到的所有用户信息，写入到浏览器的request域中
request.setAttribute("lists", list);
//将查询到的所有用户信息转发到index.jsp页面进行显示
request.getRequestDispatcher("index.jsp").forward(request, response);
}
}
AddUserServlet.java
package com.controller;
import com.pojo.User;
import com.service.ServiceImpl;
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 java.io.IOException;
@WebServlet("/AddUserServlet")
public class AddUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码集
request.setCharacterEncoding("utf-8");
//获取页面提交的数据
String username = request.getParameter("username");
String password = request.getParameter("password");
//把获取到的用户信息封装到user实体类对象中去
User user = new User();
user.setUsername(username);
user.setPassword(password);
System.out.println(user);
//调用service
ServiceImpl userService = new ServiceImpl();
//添加功能，要么成功要么失败，update方法如果添加成功返回>0
int a = userService.addUser(user);
if (a == 1) {
//添加成功后，重定向显示所有用户的页面,这里为了直接跳到查询后的页面，直接重定向到ShowUserServlet
response.sendRedirect("http://localhost:8080/ShowUserServlet");
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}
DeleteUserServlet.java
package com.controller;
import com.service.ServiceImpl;
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 java.io.IOException;
@WebServlet("/DeleteUserServlet")
public class DeleteUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置编码集
request.setCharacterEncoding("utf-8");
// 获取id,根据id来删除,getParameter()方法返回的是String类型
String id = request.getParameter("id");
//注入service层
ServiceImpl service = new ServiceImpl();
//调用service层的删除方法
int a = service.deleteUser(id);
if (a == 1) {
//删除成功后，重定向显示所有用户的页面
response.sendRedirect("http://localhost:8080/ShowUserServlet");
}
}
}
DeleteAllUserServlet.java
package com.controller;
import com.service.ServiceImpl;
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 java.io.IOException;
@WebServlet("/DeleteAllUserServlet")
public class DeleteAllUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//注入service层
ServiceImpl service = new ServiceImpl();
//调用service层的删除方法
int a = service.deleteAllUser();
if (a == 1) {
//删除成功后，重定向显示所有用户的页面
response.sendRedirect("http://localhost:8080/ShowUserServlet");
}
}
}
UpdateUserServlet.java
package com.controller;
import com.service.ServiceImpl;
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 java.io.IOException;
import java.util.Map;
//先根据id查询
@WebServlet("/UpdateUserServlet")
public class UpdateUserServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//修改之前先查询，用作修改的回显
//根据id来修改
request.setCharacterEncoding("utf-8");
String id = request.getParameter("id");
//注入service层
ServiceImpl service = new ServiceImpl();
//调用service层方法,将String类型的id强转为int类型
Map<String, Object> map = service.toUpdate(Integer.parseInt(id));
System.out.println(map);
//写入浏览器
request.setAttribute("map", map);
//转发到update.jsp页面
request.getRequestDispatcher("update.jsp").forward(request, response);
}
}
FinalUpdateServlet.java
package com.controller;
import com.pojo.User;
import com.service.ServiceImpl;
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 java.io.IOException;
@WebServlet("/FinalUpdateServlet")
public class FinalUpdateServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置字符集
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
//获取页面上所有提交的参数
String id = request.getParameter("id");
String username = request.getParameter("username");
String password = request.getParameter("password");
//封装到user实体中
User user = new User();
//使用Integer.parseInt(id)将String类型的id转为Int类型
user.setId(Integer.parseInt(id));
user.setUsername(username);
user.setPassword(password);
//调用service层方法
ServiceImpl service = new ServiceImpl();
boolean updateUser = service.updateUser(user);
if (updateUser == true) {
response.sendRedirect("/ShowUserServlet");
}
}
}