第一个JSP+Servlet+JavaBean+JDBC示例程序

运行环境

Apache Tomcat 8.0.33
JDK 1.8.0_92
IntelliJ IDEA 2016.1.1
MySql 5.7.12
UbuntuKylin 16.04

一、在MYSQL中新建表并插入测试数据

create database test_jsp;
use test_jsp;
create table dbuser(
userId int auto_increment primary key,
userName varchar(50), 
userPasswd varchar(50)
);
insert into dbuser values(1,'admin','admin');

二、在idea中创建web项目，并建立带包结构。

idea项目列表

三、编写首页登陆界面

<%@ page contentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8"%>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>第一个JSP+Servlet+JavaBean+JDBC程序示例</title>
    <style type="text/css">
      body{
        color : #000 ;
        font-size : 12px ;
        margin : 0px auto ;
      }
    </style>
    <script type="text/javascript">
      function check(form){
        //document.forms.form1.username.value取得form1中Username的值 并判断是否为空
        if(document.forms.form1.username.value==""){
          //如果 为""则弹出提示
          alert("请输入用户名");
          //将输入焦点定位到没有输入的地方
          document.forms.form1.username.focus();
          //返回错误
          return false;
        }
        if(document.forms.form1.password.value==""){
          alert("请输入密码");
          document.forms.form1.password.focus();
          return false;
        }
      }
    </script>
  </head>
  <body>
  <form action="LoginServlet" method="post" name="form1">
    <table border="1" cellspacing="1" cellpadding="1"  bordercolor="silver" align="center">
      <tr>
        <td colspan="2" align="center" bgcolor="#e8e8e8">用户登陆</td>
      </tr>
      <tr>
        <td>用户名：</td>
        <td><input type="text" name="username"/></td>
      </tr>
      <tr>
        <td>密码：</td>
        <td><input type="password" name="password"/></td>
      </tr>
      <tr>
        <td></td>
        <!-- onclick="return check(this) 调用上面的Script进行验证 -->
        <td><input type="submit" name="submit" onclick="return check(this);"/><input type="reset" name="reset"/></td>
      </tr>
    </table>
  </form>
  </body>
</html>

登陆首页截图

四、编写userBean

package beans;

public class UserBean {
    public String username;
    public String password;

    public UserBean() {
        super();
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }
}

五、编写工具类DBConn

package utils;

import java.sql.*;

public class DBConn {
    public static String driver;//定义驱动
    public static String url;//定义URL
    public static String server;
    public static String dbname;
    public static String user;
    public static String pass;
    public static String port;
    public static Connection conn;//定义连接
    public static Statement stmt;//定义STMT
    public ResultSet rs;//定义结果集
    //设置CONN
    static{
        try {
            driver="com.mysql.jdbc.Driver";
            dbname="test_jsp";
            server="localhost";
            user="root";
            pass="root";
            port="3306";
            url="jdbc:mysql://"+server+":"+port+"/"+dbname+"?user="+user+"&password="+pass;
            Class.forName(driver);
            conn = DriverManager.getConnection(url);
            System.out.println("-------连接成功------");
        } catch(ClassNotFoundException classnotfoundexception) {
            classnotfoundexception.printStackTrace();
            System.err.println("db: " + classnotfoundexception.getMessage());
        } catch(SQLException sqlexception) {
            System.err.println("db.getconn(): " + sqlexception.getMessage());
        }
    }
    //构造函数，默认加裁配置文件为jdbc.driver
    public DBConn(){
        this.conn=this.getConn();
    }
    //返回Conn
    public Connection getConn(){
        return this.conn;
    }
    //执行插入
    public void doInsert(String sql) {
        try {
            stmt = conn.createStatement();
            int i = stmt.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeInset:" + sqlexception.getMessage());
        }finally{

        }
    }
    //执行删除
    public void doDelete(String sql) {
        try {
            stmt = conn.createStatement();
            int i = stmt.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeDelete:" + sqlexception.getMessage());
        }
    }
    //执行更新
    public void doUpdate(String sql) {
        try {
            stmt = conn.createStatement();
            int i = stmt.executeUpdate(sql);
        } catch(SQLException sqlexception) {
            System.err.println("db.executeUpdate:" + sqlexception.getMessage());
        }
    }
    //查询结果集
    public ResultSet doSelect(String sql) {
        try {
            conn=DriverManager.getConnection(url);
            stmt = conn.createStatement(java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,java.sql.ResultSet.CONCUR_READ_ONLY);
            rs = stmt.executeQuery(sql);
            System.out.println("取得结果集");
        } catch(SQLException sqlexception) {
            System.err.println("db.executeQuery: " + sqlexception.getMessage());
        }
        return rs;
    }
    /**
     *关闭数据库结果集，数据库操作对象，数据库链接
     @Function: Close all the statement and conn int this instance and close the parameter ResultSet
     @Param: ResultSet
     @Exception: SQLException,Exception
     **/
    public void close(ResultSet rs) throws SQLException, Exception {

        if (rs != null) {
            rs.close();
            rs = null;
        }

        if (stmt != null) {
            stmt.close();
            stmt = null;
        }

        if (conn != null) {
            conn.close();
            conn = null;
        }
    }

    /**
     *关闭数据库操作对象，数据库连接对象
     * Close all the statement and conn int this instance
     * @throws SQLException
     * @throws Exception
     */
    public void close() throws SQLException, Exception {
        if (stmt != null) {
            stmt.close();
            stmt = null;
        }

        if (conn != null) {
            conn.close();
            conn = null;
        }
    }
}

六、编写JavaBean CheckUser

package model;

import java.sql.ResultSet;
import java.sql.SQLException;

import utils.DBConn;
import beans.UserBean;

public class CheckUser {
    public boolean checkUsre(UserBean user){
        if(user.username.equals("")||user.username!=null){
            ResultSet rs=null;
            DBConn db=new DBConn();
            rs=db.doSelect("select * from dbuser where userName='"+user.getUsername()+"' && userPasswd='"+user.getPassword()+"'");
            try {
                if(rs.next()){
                    return true;
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return false;
    }
}

七、编写Servlet,LoginServlet.java

package servlet;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

import model.CheckUser;
import beans.UserBean;

public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //设置HTTP响应的文档类型,此处为Text/html,如果更改为application\msword则设置为word文档格式  
        response.setContentType("text/html;charset=UTF-8");
        //设置响应所采用的编码方式  
        response.setCharacterEncoding("UTF-8");
        //取得参数username的值  
        String uname=request.getParameter("username");
        String passwd=request.getParameter("password");


        UserBean user=new UserBean();
        user.setUsername(uname);
        user.setPassword(passwd);
        CheckUser cku=new CheckUser();
        boolean bool=cku.checkUsre(user);

        String forward;
        if(bool){
            forward="success.jsp";

        }else{
            forward="error.jsp";
        }
        RequestDispatcher rd=request.getRequestDispatcher(forward);
        rd.forward(request,response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request,response);
    }
}

八、在web.xml中配置Servlet

配置关键代码

<servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>servlet.LoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/LoginServlet</url-pattern>
    </servlet-mapping>

此项目整个web.xml代码

<?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_3_1.xsd"
         version="3.1">
    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>servlet.LoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/LoginServlet</url-pattern>
    </servlet-mapping>
</web-app>

九、编写错误页面及成功登陆页面

error.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8"%>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>登陆错误页面</title>
</head>
<body>
Sorry!你的登陆信息不正确!系统无法让你登陆!<a href="index.jsp">点击返回</a>
</body>
</html>

登陆错误页面截图
success.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" pageEncoding="UTF-8"%>
<jsp:useBean id="user" class="beans.UserBean" scope="request"/>
<jsp:setProperty name="user" property="*"/>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>登陆成功页面</title>
</head>
<body>
<%
    session.setAttribute("user",user);
    String username=user.getUsername();
%>

<%=username %>,欢迎您!<br>
您的IP是:<%=request.getRemoteAddr() %><br>
你的主机是:<%=request.getRemoteHost() %><br>
你使用的协议是:<%=request.getProtocol() %><br>
你目前的地址是:<%=request.getRealPath("/") %><br>
你的主机端口是:<%=request.getRemotePort() %>
</body>
</html>

登陆成功截图

此文章根据http://jzgl-javaeye.iteye.com/blog/647946实践并自行修改

小程子

第一个JSP+Servlet+JavaBean+JDBC示例程序

运行环境

一、在MYSQL中新建表并插入测试数据

二、在idea中创建web项目，并建立带包结构。

三、编写首页登陆界面

四、编写userBean

五、编写工具类DBConn

六、编写JavaBean CheckUser

七、编写Servlet,LoginServlet.java

八、在web.xml中配置Servlet

九、编写错误页面及成功登陆页面

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