基于servlet+jsp框架的管理系统：简单实现增、删、改、查。
在上一条博客中的代码基础上，进行修改。
第一步：
将原先的UserDao名字改成IUserDao，新建一个impl包，在包里新建UserDaoImpl.java
IUserDao:
package com.zhongruan.dao;
import com.zhongruan.model.User;
import java.util.List;
public interface IUserDao {
User findUserByUsername(String username);
List<User>findAll();
void delete(int id);
void addServlet(String username, String password);
void update(int id, String username, String password);
}
UserDaoImpl:
public class UserDaoImpl implements IUserDao {
@Override
public User findUserByUsername(String username) {
User user=null;
Connection connection=null;
PreparedStatement statement=null;
ResultSet resultSet=null;
try{
connection=DBUtil.getConnection();
String sql="select * from account where username=?";
statement=connection.prepareStatement(sql);
statement.setString(1,username);
resultSet=statement.executeQuery();
while (resultSet.next()){
user=new User();
user.setId(resultSet.getInt(1));
user.setUsername(username);
user.setPassword(resultSet.getString(3));
}
}catch (Exception e){
e.printStackTrace();
}finally {
DBUtil.closeAll(resultSet,statement,connection);
}
return user;
}
@Override
public List<User> findAll() {
ResultSet resultSet = null;
PreparedStatement statement = null;
Connection connection = null;
List<User>users = new ArrayList<>();
try {
connection = DBUtil.getConnection();
String sql = "select * from account";
statement = connection.prepareStatement(sql);
resultSet = statement.executeQuery();
while (resultSet.next()) {
User user = new User();
user.setId(resultSet.getInt(1));
user.setUsername(resultSet.getString(2));
user.setPassword(resultSet.getString(3));
users.add(user);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
DBUtil.closeALL(resultSet, statement, connection);
}
return users;
}
@Override
public void delete(int id) {
Connection connection=null;
PreparedStatement statement=null;
try {
connection=DBUtil.getConnection();
statement=connection.prepareStatement("delete from account where id=?");
statement.setInt(1,id);
statement.executeUpdate();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeAll(null,statement,connection);
}
}
@Override
public void addServlet(String username, String password) {
Connection connection=null;
PreparedStatement statement=null;
try {
connection=DBUtil.getConnection();
statement=connection.prepareStatement("insert into account(username,password) values (?,?)");
statement.setString(1,username);
statement.setString(2,password);
statement.executeUpdate();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeAll(null,statement,connection);
}
}
@Override
public void update(int id, String username, String password) {
Connection connection=null;
PreparedStatement statement=null;
try {
connection=DBUtil.getConnection();
statement=connection.prepareStatement("update account set username=?,password=? where id=?");
statement.setString(1,username);
statement.setString(2,password);
statement.setInt(3,id);
statement.executeUpdate();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.closeAll(null,statement,connection);
}
}
}
在service新建一个impl包，在包里新建UserServiceImpl.java
UserServiceImpl :
package com.zhongruan.service.impl;
import com.zhongruan.dao.IUserDao;
import com.zhongruan.dao.impl.UserDaoImpl;
import com.zhongruan.model.User;
import com.zhongruan.service.IUserService;
import java.util.List;
public class UserServiceImpl implements IUserService {
IUserDao userDao=new UserDaoImpl();
@Override
public Boolean login(String username, String password) {
User user=userDao.findUserByUsername(username);
if (user!=null&&user.getPassword().equals(password)){
return true;
}else {
return false;
}
}
@Override
public List<User> findAll() {
List<User> users=userDao.findAll();
return users;
}
@Override
public void delete(int id2) {
userDao.delete(id2);
}
@Override
public void add(String username, String password) {
userDao.addServlet(username,password);
}
@Override
public void update(int id, String username, String password) {
userDao.update(id,username,password);
}
}
将UserService改成IUserService
IUserService:
package com.zhongruan.service;
import com.zhongruan.model.User;
import java.util.List;
public interface IUserService {
Boolean login(String username, String password);
List<User> findAll();
void delete(int id2);
void add(String username, String password);
void update(int id, String username, String password);
}
新建一个servlet包，新建五个java，分别为FindServlet / LoginServlet / DeleteServlete /AddServlet /UpdateServlet。
FindServlet:
package com.zhongruan.servlet;
import com.zhongruan.model.User;
import com.zhongruan.service.IUserService;
import com.zhongruan.service.impl.UserServiceImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;
public class FindServlet extends HttpServlet {
IUserService userService=new UserServiceImpl();
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
List<User> users=userService.findAll();
HttpSession session=req.getSession();
session.setAttribute("userlist",users);
req.getRequestDispatcher("allUser.jsp").forward(req,resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
List<User> users=userService.findAll();
HttpSession session=req.getSession();
session.setAttribute("userlist",users);
req.getRequestDispatcher("allUser.jsp").forward(req,resp);
}
}
LoginServlet:
package com.zhongruan.servlet;
import com.zhongruan.dao.IUserDao;
import com.zhongruan.model.User;
import com.zhongruan.service.IUserService;
import com.zhongruan.service.impl.UserServiceImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;
public class LoginServlet extends HttpServlet{
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username=req.getParameter("username");
String password=req.getParameter("password");
IUserService userService= new UserServiceImpl();
Boolean flag=userService.login(username,password);
if (flag) {
req.getRequestDispatcher("/find").forward(req, resp);
} else {
req.getRequestDispatcher("failure.jsp").forward(req, resp);
}
}
}
DeleteServlete:
package com.zhongruan.servlet;
import com.zhongruan.service.IUserService;
import com.zhongruan.service.impl.UserServiceImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class DeleteServlete extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String id1=req.getParameter("id");
int id2=Integer.parseInt(id1);
IUserService userService=new UserServiceImpl();
userService.delete(id2);
req.getRequestDispatcher("/find").forward(req, resp);
}
}
AddServlet:
import com.zhongruan.service.IUserService;
import com.zhongruan.service.impl.UserServiceImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class AddServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username=req.getParameter("username");
String password=req.getParameter("password");
IUserService userService= new UserServiceImpl();
userService.add(username,password);
req.getRequestDispatcher("/find").forward(req, resp);
}
}
UpdateServlet :
package com.zhongruan.servlet;
import com.zhongruan.service.IUserService;
import com.zhongruan.service.impl.UserServiceImpl;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
public class UpdateServlet extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
String username=req.getParameter("username");
String password=req.getParameter("password");
String id1=req.getParameter("id");
int id2=Integer.parseInt(id1);
IUserService userService=new UserServiceImpl();
userService.update(id2,username,password);
req.getRequestDispatcher("/find").forward(req, resp);
}
}
更改web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0">
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>com.zhongruan.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>DeleteServlet</servlet-name>
<servlet-class>com.zhongruan.servlet.DeleteServlete</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>DeleteServlet</servlet-name>
<url-pattern>/delete</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>FindServlet</servlet-name>
<servlet-class>com.zhongruan.servlet.FindServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>FindServlet</servlet-name>
<url-pattern>/find</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>AddServlet</servlet-name>
<servlet-class>com.zhongruan.servlet.AddServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AddServlet</servlet-name>
<url-pattern>/add</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>UpdateServlet</servlet-name>
<servlet-class>com.zhongruan.servlet.UpdateServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>UpdateServlet</servlet-name>
<url-pattern>/update</url-pattern>
</servlet-mapping>
</web-app>
添加addUser.jsp:
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" isELIgnored="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>新增用户</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- 引入 Bootstrap -->
<link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
基于servlet+jsp框架的管理系统：简单实现增、删、改、查。
</h1>
</div>
</div>
</div>
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small>新增用户</small>
</h1>
</div>
</div>
</div>
<form action="/add" method="post">
<%--用 户 id：<input type="text" name="id"><br><br><br>--%>
用户姓名：<input type="text" name="username"><br><br><br>
用户密码：<input type="text" name="password"><br><br><br>
<input type="submit" value="添加" >
</form>
</div>
添加update.jsp
<%--
Created by IntelliJ IDEA.
User: MyPC
Date: 2019/9/29
Time: 14:45
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>修改</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- 引入 Bootstrap -->
<link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
基于servlet+jsp框架的管理系统：简单实现增、删、改、查。
</h1>
</div>
</div>
</div>
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small>修改用户</small>
</h1>
</div>
</div>
</div>
<form action="/update" method="post">
用 户 id：<input type="text" name="id"><br><br><br>
用户姓名：<input type="text" name="username"><br><br><br>
用户密码：<input type="text" name="password"><br><br><br>
<input type="submit" value="更改" >
</form>
</div>
</body>
</html>
新建allUrer
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8" isELIgnored="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>user列表</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<!-- 引入 Bootstrap -->
<link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
<div class="container">
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
基于servlet+jsp框架的管理系统：简单实现增、删、改、查。
</h1>
</div>
</div>
</div>
<div class="row clearfix">
<div class="col-md-12 column">
<div class="page-header">
<h1>
<small>用户列表 —— 显示所有用户</small>
</h1>
</div>
</div>
</div>
<div class="row">
<div class="col-md-4 column">
<a class="btn btn-primary" href="addUser.jsp">新增</a>
</div>
</div>
<div class="row clearfix">
<div class="col-md-12 column">
<table class="table table-hover table-striped">
<thead>
<tr>
<th>id</th>
<th>用户名</th>
<th>密码</th>
<th>操作</th>
</tr>
</thead>
<tbody>
<c:forEach var="user" items="${userlist}">
<tr>
<td>${user.id}</td>
<td>${user.username}</td>
<td>${user.password}</td>
<td>
<a href="/delete?id=${user.id}">删除</a>|
<a href="updateUser.jsp">修改</a>
</td>
</tr>
</c:forEach>
</tbody>
</table>
</div>
</div>
</div>