需要使用的 技术 工具:
- idea 2022 开发工具
- MySql 5.6 数据库工具
- Apache Tomcat 8.5.85 web应用部署工具
主要功能有:
涉及到的知识:
先打开数据库 创建一个数据库 然后 创建对应的表结构- CREATE TABLE `user` (
- `id` int(11) NOT NULL auto_increment,
- `name` varchar(255) NOT NULL,
- `pwd` varchar(255) NOT NULL,
- `sex` varchar(255) NOT NULL,
- `address` varchar(255) NOT NULL,
- `info` varchar(255) NOT NULL,
- PRIMARY KEY (`id`)
- ) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
-
- INSERT INTO `user` VALUES ('1', '123', '123', '女', '北京', '123');
- INSERT INTO `user` VALUES ('2', '111, '111', '男', '北京', '123123');
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然后打开 idea 创建以下 几个目录:
com.filter //过滤器 解决中文字符集乱码
com.util //数据库连接工具类
com.entity //实体类
com.dao //数据操作类
com.servlet //servlet类
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在filter下新建一个EncodingFilter用来解决中文字符集乱码,需要实现Filter接口,并且重写doFilter函数- package com.filter;
-
- import java.io.IOException;
-
- import javax.servlet.Filter;
- import javax.servlet.FilterChain;
- import javax.servlet.FilterConfig;
- import javax.servlet.ServletException;
- import javax.servlet.ServletRequest;
- import javax.servlet.ServletResponse;
-
- public class EncodingFilter implements Filter{
- public EncodingFilter(){
- System.out.println("过滤器构造");
- }
- public void destroy() {
- System.out.println("过滤器销毁");
- }
- public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {
- request.setCharacterEncoding("utf-8"); //将编码改为utf-8
- response.setContentType("text/html;charset=utf-8");
- chain.doFilter(request, response);
- }
-
- public void init(FilterConfig arg0) throws ServletException {
- System.out.println("过滤器初始化");
- }
-
- }
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然后到web.xml下进行对EncodingFilter相应的 xml配置- <?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">
-
- <filter>
- <filter-name>EncodingFilter</filter-name>
- <filter-class>com.filter.EncodingFilter</filter-class>
- </filter>
- <filter-mapping>
- <filter-name>EncodingFilter</filter-name>
- <url-pattern>/*</url-pattern>
- </filter-mapping>
-
- <welcome-file-list>
- <welcome-file>login.jsp</welcome-file>
- </welcome-file-list>
- </web-app>
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在util下新建一个DBconn类用来处理对数据库的连接操作(用户名和密码需要对照自己的数据库进行更改)- package com.util;
- import java.sql.*;
- public class DBConnection {
- //定义连接数据库的属性
- private static String JDBC_DRIVER = "com.mysql.jdbc.Driver";
- private static String url = "jdbc:mysql://localhost:3306/demo";
- // 用户 密码
- private static String username = "root";
- private static String pwd = "123456";
- private static Connection conn = null;
- static ResultSet rs = null;
- static PreparedStatement ps =null;
-
- public static void init(){
- try {
- Class.forName(JDBC_DRIVER);
- conn = DriverManager.getConnection(url,username,pwd);
- } catch (Exception e) {
- System.out.println("init [SQL驱动程序初始化失败!]");
- e.printStackTrace();
- }
- }
- public static int addUpdDel(String sql){
- int i = 0;
- try {
- PreparedStatement ps = conn.prepareStatement(sql);
- i = ps.executeUpdate();
- } catch (SQLException e) {
- System.out.println("数据库增删改异常");
- e.printStackTrace();
- }
- return i;
- }
- public static ResultSet selectSql(String sql){
- try {
- ps = conn.prepareStatement(sql);
- rs = ps.executeQuery(sql);
- } catch (SQLException e) {
- System.out.println("数据库查询异常");
- e.printStackTrace();
- }
- return rs;
- }
- public static void closeConn(){
- try {
- conn.close();
- } catch (SQLException e) {
- System.out.println("数据库关闭异常");
- e.printStackTrace();
- }
- }
- }
复制代码 在entity下新建一个User实体类 对应数据库中的每个字段- package com.entity;
- public class User {
- private int id;
- private String name;
- private String pwd;
- private String sex;
- private String address;
- private String info;
- 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 String getPwd() {
- return pwd;
- }
- public void setPwd(String pwd) {
- this.pwd = pwd;
- }
- public String getSex() {
- return sex;
- }
- public void setSex(String sex) {
- this.sex = sex;
- }
- public String getAddress() {
- return address;
- }
- public void setAddress(String address) {
- this.address = address;
- }
- public String getInfo() {
- return info;
- }
- public void setInfo(String info) {
- this.info = info;
- }
- }
复制代码 在dao下新建一个UserDao接口 以及对应的方法实现类 规范开发 需要使用 接口及实现类
UserDao.java- package com.dao;
- import com.entity.User;
- import java.util.List;
- public interface UserDao {
- public boolean login(String name,String pwd);//登录
- public boolean register(User user);//注册
- public List<User> getUserAll();//返回用户信息集合
- public boolean delete(int id) ;//根据id删除用户
- public boolean update(int id,String name, String pwd,String sex, String home,String info) ;//更新用户信息
- }
复制代码 在写一个 UserDaoImpl.java 实现UserDao接口,及未实现的方法- package com.dao;
- import com.entity.User;
- import com.util.DBConnection;
- import java.sql.ResultSet;
- import java.sql.SQLException;
- import java.util.ArrayList;
- import java.util.List;
- public class UserDaoImpl implements UserDao {
- DBConnection DBconn = new DBConnection();
- // 注册用户
- @Override
- public boolean register(User user) {
- boolean flag = false;
- DBconn.init();
- int i =DBconn.addUpdDel("insert into user(name,pwd,sex,address,info) " +
- "values('"+user.getName()+"','"+user.getPwd()+"','"+user.getSex()+"','"+user.getAddress()+"','"+user.getInfo()+"')");
- if(i>0){
- flag = true;
- }
- DBconn.closeConn();
- return flag;
- }
- // 查询 登录用户是否存在
- @Override
- public boolean login(String name, String pwd) {
- boolean flag = false;
- try {
- DBconn.init();
- ResultSet rs = DBconn.selectSql("select * from user where name='"+name+"' and pwd='"+pwd+"'");
- while(rs.next()){
- if(rs.getString("name").equals(name) && rs.getString("pwd").equals(pwd)){
- flag = true;
- }
- }
- DBconn.closeConn();
- } catch (SQLException e) {
- e.printStackTrace();
- }
- return flag;
- }
- // 获取用户
- @Override
- public List<User> getUserAll() {
- List<User> list = new ArrayList<User>();
- try {
- DBconn.init();
- ResultSet rs = DBconn.selectSql("select * from user");
- while(rs.next()){
- User user = new User();
- user.setId(rs.getInt("id"));
- user.setName(rs.getString("name"));
- user.setPwd(rs.getString("pwd"));
- user.setSex(rs.getString("sex"));
- user.setAddress(rs.getString("address"));
- user.setInfo(rs.getString("info"));
- list.add(user);
- }
- DBconn.closeConn();
- return list;
- } catch (SQLException e) {
- e.printStackTrace();
- }
- return null;
- }
- // 更新用户数据
- @Override
- public boolean update(int id, String name, String pwd, String sex, String home, String info) {
- boolean flag = false;
- DBconn.init();
- String sql ="update user set name ='"+name
- +"' , pwd ='"+pwd
- +"' , sex ='"+sex
- +"' , home ='"+home
- +"' , info ='"+info+"' where id = "+id;
- int i =DBconn.addUpdDel(sql);
- if(i>0){
- flag = true;
- }
- DBconn.closeConn();
- return flag;
- }
- // 删除用户
- @Override
- public boolean delete(int id) {
- boolean flag = false;
- DBconn.init();
- String sql = "delete from user where id="+id;
- int i =DBconn.addUpdDel(sql);
- if(i>0){
- flag = true;
- }
- DBconn.closeConn();
- return flag;
- }
- }
复制代码 在servlet下创建DengluServlet用来实现对用户登录的操作 ,实现Servlet具体内容,然后需要去WEB_INF下的web.xml去配置servlet- package com.servlet;
- import com.dao.UserDao;
- import com.dao.UserDaoImpl;
- import javax.servlet.*;
- import javax.servlet.http.*;
- import javax.servlet.annotation.*;
- import java.io.IOException;
- @WebServlet(name = "signinServlet", value = "/signinServlet")
- public class Signin extends HttpServlet { // serverlet 需要继承 HttpServerlet 并重写doGet和doPost方法
- @Override
- protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
- doPost(request, response); //将信息使用doPost方法执行 对应jsp页面中的form表单中的method
- }
- @Override
- protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
- String name = request.getParameter("name"); //得到jsp页面传过来的参数
- String pwd = request.getParameter("pwd");
- UserDao ud = new UserDaoImpl();
- if(ud.login(name, pwd)){
- request.setAttribute("xiaoxi", "欢迎用户"+name); //向request域中放置信息
- request.getRequestDispatcher("/success.jsp").forward(request, response);//转发到成功页面
- }else{
- response.sendRedirect("index.jsp"); //重定向到首页
- }
- }
- }
复制代码 两点要注意的地方:
一:getParameter与getAttribute两者的区别
request.setAttribute("xiaoxi", "欢迎用户"+name);//向request域中放置信息 ( 键值对的形式) 名字为xiaoxi 内容为"欢迎用户"+name
request.getAttribute("xiaoxi");//得到request域中放置名字为xiaoxi的信息
request.getParameter("name");//得到request域的参数信息(得到jsp页面传过来的参数)
getAttribute表示从request范围取得设置的属性,必须要先setAttribute设置属性,才能通过getAttribute来取得,设置与取得的为Object对象类型 。
getParameter表示接收参数,参数为页面提交的参数,包括:表单提交的参数、URL重写(就是xxx?id=1中的id)传的参数等,因此这个并没有设置参数的方法(没有setParameter),而且接收参数返回的不是Object,而是String类型
二:转发与重定向的区别
(1).重定向的执行过程:Web服务器向浏览器发送一个http响应--》浏览器接受此响应后再发送一个新的http请求到服务器--》服务器根据此请求寻找资源并发送给浏览器。它可以重定向到任意URL,不能共享request范围内的数据。
(2).重定向是在客户端发挥作用,通过新的地址实现页面转向。
(3).重定向是通过浏览器重新请求地址,在地址栏中可以显示转向后的地址。
(4).转发过程:Web服务器调用内部方法在容器内部完成请求和转发动作--》将目标资源发送给浏览器,它只能在同一个Web应用中使用,可以共享request范围内的数据。
(5).转发是在服务器端发挥作用,通过forward()方法将提交信息在多个页面间进行传递。
(6).转发是在服务器内部控制权的转移,客户端浏览器的地址栏不会显示出转向后的地址。
在servlet下创建一个ZhuceServlet用来实现用户注册的操作- package com.servlet;
- import com.dao.UserDao;
- import com.dao.UserDaoImpl;
- import com.entity.User;
- 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(name = "LogonServlet", value = "/LogonServlet")
- public class Logon extends HttpServlet{
- @Override
- protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- super.doGet(req, resp);
- }
- @Override
- protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- String name = req.getParameter("name"); //获取jsp页面传过来的参数
- String pwd = req.getParameter("pwd");
- String sex = req.getParameter("sex");
- String address = req.getParameter("address");
- String info = req.getParameter("info");
- User user = new User(); //实例化一个对象,组装属性
- user.setName(name);
- user.setPwd(pwd);
- user.setSex(sex);
- user.setAddress(address);
- user.setInfo(info);
- UserDao ud = new UserDaoImpl();
- if( ud.register(user) ){
- req.setAttribute("username", name); //向req域中放置参数
- req.setAttribute("xiaoxi", "注册成功");
- req.getRequestDispatcher("/login.jsp").forward(req, resp); //转发到登录页面
- }else{
- resp.sendRedirect("login.jsp");//重定向到首页
- }
- }
- }
复制代码 在servlet下创建SearchallServlet用来返回数据库中所有用户信息 Searchall.java- package com.servlet;
- import com.dao.UserDao;
- import com.dao.UserDaoImpl;
- import com.entity.User;
- 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(name = "SearchallServlet", value = "/SearchallServlet")
- public class Searchall extends HttpServlet {
- @Override
- protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- super.doGet(req, resp);
- }
- @Override
- protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- UserDao ud = new UserDaoImpl();
- List<User> userAll = ud.getUserAll();
- req.setAttribute("userAll", userAll);
- req.getRequestDispatcher("/showall.jsp").forward(req, resp);
- }
- }
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在servlet下创建DeleteServlet用来删除用户操作 DeleteServlet.java- package com.servlet;
- import com.dao.UserDao;
- import com.dao.UserDaoImpl;
- 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(name = "DeleteServlet", value = "/DeleteServlet")
- public class Delete extends HttpServlet {
- @Override
- protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- super.doGet(req, resp);
- }
- @Override
- protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- String id = req.getParameter("id");
- int userId = Integer.parseInt(id);
- UserDao ud = new UserDaoImpl();
- if(ud.delete(userId)){
- req.setAttribute("xiaoxi", "删除成功");
- req.getRequestDispatcher("/Searchall").forward(req, resp);
- }else{
- resp.sendRedirect("index.jsp");
- }
- }
- }
复制代码 在servlet下创建UpdateServlet操作用来更新用户信息 UpdateServlet.java- [/code][code]package com.servlet;
- import com.dao.UserDao;
- import com.dao.UserDaoImpl;
- 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(name = "UpdateServlet", value = "/UpdateServlet")
- public class Update extends HttpServlet {
- @Override
- protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- super.doGet(req, resp);
- }
- @Override
- protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
- String id = req.getParameter("id");
- int userId = Integer.parseInt(id);
- String name = req.getParameter("name");
- String pwd = req.getParameter("pwd");
- String sex = req.getParameter("sex");
- String home = req.getParameter("home");
- String info = req.getParameter("info");
- System.out.println("------------------------------------"+userId);
- UserDao ud = new UserDaoImpl();
- if(ud.update(userId, name, pwd, sex, home, info)){
- req.setAttribute("xiaoxi", "更新成功");
- req.getRequestDispatcher("/Searchall").forward(req, resp);
- }else{
- resp.sendRedirect("index.jsp");
- }
- }
- }
复制代码
配置servlet - <?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">
-
- <filter>
- <filter-name>EncodingFilter</filter-name>
- <filter-class>com.filter.EncodingFilter</filter-class>
- </filter>
- <filter-mapping>
- <filter-name>EncodingFilter</filter-name>
- <url-pattern>/*</url-pattern>
- </filter-mapping>
- <servlet>
- <servlet-name>LogonServlet</servlet-name>
- <servlet-class>com.servlet.Logon</servlet-class>
- </servlet>
- <servlet>
- <servlet-name>SigninServlet</servlet-name>
- <servlet-class>com.servlet.Signin</servlet-class>
- </servlet>
- <servlet>
- <servlet-name>SearchallServlet</servlet-name>
- <servlet-class>com.servlet.Searchall</servlet-class>
- </servlet>
- <servlet>
- <servlet-name>DeleteServlet</servlet-name>
- <servlet-class>com.servlet.Delete</servlet-class>
- </servlet>
- <servlet>
- <servlet-name>UpdateServlet</servlet-name>
- <servlet-class>com.servlet.Update</servlet-class>
- </servlet>
-
- <servlet-mapping>
- <servlet-name>LogonServlet</servlet-name>
- <url-pattern>/LogonServlet</url-pattern>
- </servlet-mapping>
- <servlet-mapping>
- <servlet-name>SigninServlet</servlet-name>
- <url-pattern>/SigninServlet</url-pattern>
- </servlet-mapping>
- <servlet-mapping>
- <servlet-name>SearchallServlet</servlet-name>
- <url-pattern>/SearchallServlet</url-pattern>
- </servlet-mapping>
- <servlet-mapping>
- <servlet-name>DeleteServlet</servlet-name>
- <url-pattern>/DeleteServlet</url-pattern>
- </servlet-mapping>
- <servlet-mapping>
- <servlet-name>UpdateServlet</servlet-name>
- <url-pattern>/UpdateServlet</url-pattern>
- </servlet-mapping>
-
- <welcome-file-list>
- <welcome-file>login.jsp</welcome-file>
- </welcome-file-list>
- </web-app>
复制代码
新建jsp页面 login- <%@ page contentType="text/html;charset=UTF-8" language="java" %>
- <html>
- <head>
- <title>登录页</title>
- </head>
- <body>
- <form action="SigninServlet" method="post">
- 用户名:<input type="text" name="name"value=""><br><br>
- 密码: <input type="password" name="pwd"value=""><br><br>
- <input type="submit"value="登录"name="denglu"><input type="reset"value="重置"><br>
- </form>
- <form action="zhuce.jsp">
- <input type="submit"value="新用户注册">
- </form>
- </body>
- </html>
复制代码
zhuce.jsp 用户注册页面- <%@ page contentType="text/html;charset=UTF-8" language="java" %>
- <%
- String path = request.getContextPath();
- String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
- %>
- <html>
- <head>
- <title>My JSP 'BB.jsp' starting page</title>
- </head>
- <body >
- <form action="LogonServlet"method="post" style="padding-top:-700px;">
- 输入用户名:<input name="name" type="text"><br><br>
- 输入密码:<input name="pwd" type="password"><br><br>
- 选择性别:<input type="radio"name="sex"value="男"checked>男
- <input type="radio"name="sex"value="女">女<br><br>
- 选择家乡:
- <select name="address">
- <option value="上海">上海</option>
- <option value="北京" selected>北京</option>
- <option value="纽约">纽约</option>
- </select><br>
- 填写个人信息:<br>
- <textarea name="info" row="5"cols="30"></textarea><br>
- <input type="reset"value="重置"><input type="submit"value="注册">
- </form>
- </body>
- </html>
复制代码
失败页面 index.jsp- <%@ page contentType="text/html;charset=UTF-8" language="java" %>
- <html>
- <head>
- <title></title>
- </head>
- <body>
- <p>失败</p>
- </body>
- </html>
复制代码 success.jsp 成功页面- <%@ page contentType="text/html;charset=UTF-8" language="java" %>
- <html>
- <head>
- <title>My JSP 'success.jsp' starting page</title>
- </head>
- <body>
- ${xiaoxi} <br>
- <a target="_blank" href="https://www.cnblogs.com/showall.jsp">查看所有用户</a>
- </body>
- </html>
复制代码
完成以上工作就可以 运行 Tomcat服务,然后运行啦
本博文参考大佬 http://blog.csdn.net/qq_23994787/article/details/73612870
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