目录
  • 实现步骤
    • jar包
    • 数据库的驱动以及用户密码
    • jsp页面
    • 注册页面
    • 登陆成功和失败的页面
    • 工具类
    • 登陆的类
    • 注册的类
    • 两个映射路径
  • 思路
    • 登陆
    • 注册
  • 总结

    实现步骤

    创建maven项目 配置Tomcat 这些都不细说了

    jar包

    因为要连接数据库所以一定要在maven项目下的xml文件下配置数据库的jar包依赖

        <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.28</version>
    </dependency>

    这个千万不要忘了 重重之重

    数据库的驱动以及用户密码

    package com.li.Servlet.blit;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;

public class JDBC {
    private static String url = null;
    private static String name = null;
    private static String password = null;

    static {
        try {
            Class.forName ( "com.mysql.cj.jdbc.Driver" );
        } catch (Exception e) {
            e.printStackTrace ( );
        }
        url = "jdbc:mysql://localhost:3306/zhiqingli?useUnicode=true&characterEncoding=utf8&useSSL=true";
        name = "root";
        password = "root";
    }

    public static Connection getConn() throws Exception {
        return DriverManager.getConnection ( url, name, password );
    }

    public static void release(Connection conn, PreparedStatement pst, ResultSet res) {
        try {
            if (res != null) {
                res.close ( );
            }
            if (pst != null) {
                pst.close ( );
            }
            if (conn != null) {
                conn.close ( );
            }
        } catch (Exception e) {
            e.printStackTrace ( );
        }
    }
}

    这个类可以直接复制使用，但要改成自己的数据库名字

    jsp页面

    登陆页面

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<body>
<form action="${pageContext.request.contextPath}/test" method="get">
   <h3>账号：<input type="text" name="account"></h3>
   <h3>密码：<input type="password" name="paw"></h3>
   <h3><input type="submit" value="登陆"><a href="https://www.freexyz.cn/dev/Register.jsp" rel="external nofollow"  target="_blank">注册</a></h3>
</form>
</body>
</html>

    注册页面

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
   <title>注册</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/res" method="post">
   <h3>账号：<input type="text" placeholder="请输入注册的账号" name="number"></h3>
   <h3>密码：<input type="password" placeholder="请输入注册的密码" name="word" id="one"></h3>
   <h3>确认密码：<input type="password" placeholder="确认一遍密码" name="u" id="two"></h3>
   <input type="submit" value="提交" οnclick="show()">
</form>
<Script>
function show(){
    var one = document.getElementById("one").value;
    var two = document.getElementById("two").value;
    if (one === two){
        alert("注册成功");
        window.open("index.jsp")
    }else {
        alert("两次输入的密码不一致");
    }
}
</Script>
</body>
</html>

    登陆成功和失败的页面

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>成功页面</title>
</head>
<body>
<h1>登陆成功，感谢使用</h1>
</body>
</html>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>失败页面</title>
</head>
<body>
<h1>登陆失败，账号密码找不到或者错误</h1>
</body>
</html>

    工具类

    工具人上线

    //登陆使用的方法
Connection conn = null;
  PreparedStatement pst = null;
  ResultSet res = null;
  boolean isQ;
   public boolean Select(String username,String paw)  {
      try {
          conn = JDBC.getConn ( );
          String sql = "SELECT * FROM `username` where `name`=? and `password`=?";
          pst = conn.prepareStatement (sql);
          pst.setObject ( 1,username );
          pst.setObject ( 2,paw );
          res = pst.executeQuery ( );
          if (res.next ()){
              isQ = true;
              System.out.println (res.getObject ( "name" )+" "+res.getObject ( "password" ));
              System.out.println ("登陆成功");
          }else {
              isQ = false;
              System.out.println ("登陆失败");
          }
      }catch (Exception e){
          e.printStackTrace ();
      }finally {
          JDBC.release ( conn,pst,res );
      }
      return isQ;
  }
  //注册用的方法
   public void addUser(String name,String paw){
      try {
          conn = JDBC.getConn ( );
          String sql = "insert into `username`(`name`,`password`) values (?,?)";
          pst = conn.prepareStatement ( sql );
          pst.setObject ( 1,name );
          pst.setObject ( 2,paw );
          int i = pst.executeUpdate ( );
          if (i>0){
              System.out.println ("添加成功");
          }
      }catch (Exception e){
          e.printStackTrace ();
      }finally {
          JDBC.release ( conn,pst,res );
      }
  }

    登陆的类

    package com.li.Servlet.test;

import com.li.Servlet.blit.Way;

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 index extends HttpServlet {
  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      String account = req.getParameter ( "account" );
      String paw = req.getParameter ( "paw" );
      Way way = new Way ();
      if (way.Select ( account,paw )){
          resp.sendRedirect ( "/s4/true.jsp" );
      }else {
          resp.sendRedirect ( "/s4/false.jsp" );
      }
  }

  @Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      doGet ( req, resp );
  }
}

    注册的类

    package com.li.Servlet.test;

import com.li.Servlet.blit.Way;

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 index02 extends HttpServlet {
  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      String number = req.getParameter ( "number" );
      String word = req.getParameter ( "word" );
       String u = req.getParameter ( "u" );
    if (word.equals ( u )){
          Way way = new Way ( );
          way.addUser ( number,word );
      }else {
          //当两次密码不一致的时候浏览器响应给用户当前注册的页面
          resp.sendRedirect ( "/s4/Register.jsp" );
      }
  }

  @Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      doGet ( req, resp );
  }
}

    两个映射路径

    <!--登陆-->
  <servlet>
      <servlet-name>test</servlet-name>
      <servlet-class>com.li.Servlet.test.index</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>test</servlet-name>
      <url-pattern>/test</url-pattern>
  </servlet-mapping>
<!--注册-->
  <servlet>
      <servlet-name>res</servlet-name>
      <servlet-class>com.li.Servlet.test.index02</servlet-class>
  </servlet>
  <servlet-mapping>
      <servlet-name>res</servlet-name>
      <url-pattern>/res</url-pattern>
  </servlet-mapping>

    思路

    登陆

    这个就是用户输入的账号和密码看看数据库里有没有，有的话就重定向到成功或这失败的页面，相当于浏览器响应给用户的请求结果

    注册

    相当于就是往数据库里面添加一个账号或者密码然返回到登陆页面

    这里我在注册类面没有用到重定向，而是在注册的jsp页面里判断之后跳转到登陆页面

    注意：这里为什么没在注册类里面用重定向

    因为使用重定向之后就直接返回了登陆类运行的结果

    总结

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