JSP+Servlet + JDBC 实现简单的登录验证模块
2016-08-04 18:03
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数据库设计+编码+运行调试
数据库准备：
二话不说，上图
文件组织如下：
首先写出三个JSP页面文件
login.jsp
<%@ page language="java" contentType="text/html;charset=gb2312"
pageEncoding="gb2312"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>登陆页面</title>
</head>
<body>
<center> 登陆界面</center>
<center>
<form action="login"method="post">
用户名 <input type="text" name = "username"/><br><br>
密码 <input type="text" name ="password"> <br>
<input type = "submit" value ="提交">
</form>
</center>
</body>
</html>
back.jsp
<%@ page language="java" contentType="text/html;charset=gb2312"
pageEncoding="gb2312"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>登陆失败</title>
</head>
<body>
用户密码错误，单击
<ahref="login.jsp">这里</a>
返回
</body>
</html>
welcome.jsp
<%@ page import ="java.util.*"contentType="text/html; charset=gb2312"
pageEncoding="gb2312"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>登陆成功</title>
</head>
<body>
欢迎你！登陆成功！<br>
<%
Date today = new Date();
int d = today.getDay();
int h = today.getHours();
String s = "";
if(h>0 && h< 12)
s = "上午好";
else if(h>=12)
s = "下午好";
String day[] = {"日","一","二","三","四","五","六"};
out.println(s+ "，今天是星期" + day[d]);
%>
</body>
</html>
接着，写一个数据库处理类以及一个servlet类
DBUtil.java
package javabean;
import java.sql.*;
public class DBUtil {
boolean bInited = false;
//加载驱动
public void initJDBC() throws ClassNotFoundException {
//加载MYSQL JDBC驱动程序
Class.forName("com.mysql.jdbc.Driver");
bInited = true;
System.out.println("Success loading Mysql Driver!");
}
public Connection getConnection() throwsClassNotFoundException,
SQLException{
if(!bInited){
initJDBC();
}
//连接URL为 jdbc:mysql//服务器地址/数据库名
//后面的2个参数分别是登陆用户名和密码
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/user","root","123");
return conn;
}
public boolean loginSuccess(String userName,String password){
boolean returnValue = false;
String sql = "SELECT * FROM user";
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try{
conn = getConnection();
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next()){
String userNameInDB = rs.getString("name");
String passwordInDB = rs.getString("pwd");
if(userNameInDB.equals(userName)&&
passwordInDB.equals(password)){
returnValue = true;
break;
}
}
}catch (ClassNotFoundException e) {
e.printStackTrace();
}catch (SQLException e) {
e.printStackTrace();
}
return returnValue;
}
}
LoginServlet.java
package servlet;
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javabean.DBUtil;
public class LoginServlet implements javax.servlet.Servlet{
public void destroy() {
}
public ServletConfig getServletConfig() {
return null;
}
public String getServletInfo() {
return null;
}
public void init(ServletConfig arg0) throws ServletException{
}
public void doPost(HttpServletRequestrequest,HttpServletResponse response)
throws ServletException,IOException{
String userName = request.getParameter("username");//取得用户名
String password = request.getParameter("password");//取得密码
DBUtil db = new DBUtil();//构建数据库对象
boolean canLogin = db.loginSuccess(userName, password);
if(canLogin){//根据登陆情况，跳转页面
response.sendRedirect("welcome.jsp");
}else{
response.sendRedirect("back.jsp");
}
}
public void service(ServletRequest request, ServletResponseresponse)
throws ServletException, IOException {
HttpServletRequest rq = (HttpServletRequest)request;
HttpServletResponse rs = (HttpServletResponse) response;
doPost(rq,rs);
}
}
最后，web配置文件如下：
<?xmlversion="1.0"encoding="UTF-8"?>
<web-appversion="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
</web-app>
实验注意要点
程序运行结果如下：
数据库准备：
二话不说，上图
文件组织如下：
首先写出三个JSP页面文件
login.jsp
<%@ page language="java" contentType="text/html;charset=gb2312"
pageEncoding="gb2312"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>登陆页面</title>
</head>
<body>
<center> 登陆界面</center>
<center>
<form action="login"method="post">
用户名 <input type="text" name = "username"/><br><br>
密码 <input type="text" name ="password"> <br>
<input type = "submit" value ="提交">
</form>
</center>
</body>
</html>
back.jsp
<%@ page language="java" contentType="text/html;charset=gb2312"
pageEncoding="gb2312"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>登陆失败</title>
</head>
<body>
用户密码错误，单击
<ahref="login.jsp">这里</a>
返回
</body>
</html>
welcome.jsp
<%@ page import ="java.util.*"contentType="text/html; charset=gb2312"
pageEncoding="gb2312"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=gb2312">
<title>登陆成功</title>
</head>
<body>
欢迎你！登陆成功！<br>
<%
Date today = new Date();
int d = today.getDay();
int h = today.getHours();
String s = "";
if(h>0 && h< 12)
s = "上午好";
else if(h>=12)
s = "下午好";
String day[] = {"日","一","二","三","四","五","六"};
out.println(s+ "，今天是星期" + day[d]);
%>
</body>
</html>
接着，写一个数据库处理类以及一个servlet类
DBUtil.java
package javabean;
import java.sql.*;
public class DBUtil {
boolean bInited = false;
//加载驱动
public void initJDBC() throws ClassNotFoundException {
//加载MYSQL JDBC驱动程序
Class.forName("com.mysql.jdbc.Driver");
bInited = true;
System.out.println("Success loading Mysql Driver!");
}
public Connection getConnection() throwsClassNotFoundException,
SQLException{
if(!bInited){
initJDBC();
}
//连接URL为 jdbc:mysql//服务器地址/数据库名
//后面的2个参数分别是登陆用户名和密码
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/user","root","123");
return conn;
}
public boolean loginSuccess(String userName,String password){
boolean returnValue = false;
String sql = "SELECT * FROM user";
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try{
conn = getConnection();
stmt = conn.createStatement();
rs = stmt.executeQuery(sql);
while(rs.next()){
String userNameInDB = rs.getString("name");
String passwordInDB = rs.getString("pwd");
if(userNameInDB.equals(userName)&&
passwordInDB.equals(password)){
returnValue = true;
break;
}
}
}catch (ClassNotFoundException e) {
e.printStackTrace();
}catch (SQLException e) {
e.printStackTrace();
}
return returnValue;
}
}
LoginServlet.java
package servlet;
import java.io.IOException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javabean.DBUtil;
public class LoginServlet implements javax.servlet.Servlet{
public void destroy() {
}
public ServletConfig getServletConfig() {
return null;
}
public String getServletInfo() {
return null;
}
public void init(ServletConfig arg0) throws ServletException{
}
public void doPost(HttpServletRequestrequest,HttpServletResponse response)
throws ServletException,IOException{
String userName = request.getParameter("username");//取得用户名
String password = request.getParameter("password");//取得密码
DBUtil db = new DBUtil();//构建数据库对象
boolean canLogin = db.loginSuccess(userName, password);
if(canLogin){//根据登陆情况，跳转页面
response.sendRedirect("welcome.jsp");
}else{
response.sendRedirect("back.jsp");
}
}
public void service(ServletRequest request, ServletResponseresponse)
throws ServletException, IOException {
HttpServletRequest rq = (HttpServletRequest)request;
HttpServletResponse rs = (HttpServletResponse) response;
doPost(rq,rs);
}
}
最后，web配置文件如下：
<?xmlversion="1.0"encoding="UTF-8"?>
<web-appversion="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/login</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>login.jsp</welcome-file>
</welcome-file-list>
</web-app>
实验注意要点
程序运行结果如下：
内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理 
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