javaEE之jsp+JavaBean实现登录+注册+留言功能（外挂数据库）
实现效果
#UserBean.java
package nmx;
public class UserBean {
private String username;
private String truename;
private String email;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getTruename() {
return truename;
}
public void setTruename(String truename) {
this.truename = truename;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
#login.jsp（登录页面）
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'login.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form name="form1" method="post">
用户名：<input type="text" name="username"><br>
密码 ： <input type="password" name="password"><br>
<input type="submit" value="注册" name="register" onclick="this.form.action = 'register.jsp'">
<input type="submit" value="登录" name="login" onclick="this.form.action = 'validate.jsp'">
</form>
</body>
</html>
#validate.jsp（登录验证）
<%@ page language="java" import="java.util.*,nmx.*,java.sql.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'validate.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
%>
<jsp:useBean id="userBean" class="nmx.UserBean" />
<%
String Username=request.getParameter("username");
String Password=request.getParameter("password");
Class.forName("com.mysql.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
String usename="root";
String psw="";
Connection conn=DriverManager.getConnection(url, usename, psw);
if(conn!=null){
String sql="select * from user where username='"+Username+"' and password='"+Password+"'";
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);
if(rs.next()){
userBean=new UserBean();
userBean.setUsername(rs.getString("username"));
userBean.setTruename(rs.getString("truename"));
userBean.setEmail(rs.getString("email"));
session.setAttribute("user", userBean);
response.sendRedirect("main.jsp");
}else{
response.sendRedirect("error.jsp");
}
conn.close();
}else{
out.println("数据库连接失败！");
}
%>
</body>
</html>
#main.jsp（登陆后的主页面）
<%@ page language="java" import="java.util.*,nmx.*,java.sql.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'main.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<jsp:useBean id="user" class="nmx.UserBean" scope="session" />
<%//if(user.getUsername()==null){ response.sendRedirect("login.jsp");} %>
Hello,<%=user.getUsername()%><br>
<%
Class.forName("com.mysql.jdbc.Driver");
String url="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
String usename="root";
String psw="";
Connection conn=DriverManager.getConnection(url, usename, psw);
if(conn!=null){
String sql="select * from user ";
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery(sql);
// List user_list=new ArrayList();
%>
<table border="1">
<tr>
<td>id</td><td>用户名</td><td>真实姓名</td><td>邮箱</td>
</tr>
<%
while(rs.next()){
%>
<tr>
<td><%=rs.getInt("id") %></td>
<td><%=rs.getString("username") %></td>
<td><%=rs.getString("truename") %></td>
<td><%=rs.getString("email") %></td>
</tr>
<%} %>
</table>
<%
String sql1="select * from message ";
Statement stmt1=conn.createStatement();
ResultSet rs1=stmt1.executeQuery(sql1);
%>
<table border="1">
<tr><td>用户名</td><td>留言</td></tr>
<%while(rs1.next()){ %>
<tr>
<td><%=rs1.getString("username") %></td>
<td><%=rs1.getString("message") %></td>
</tr>
<%
}%>
</table>
<% conn.close();
}else{
out.println("数据库连接失败！");
}
%>
<form action="message.jsp" method="post">
<input type="submit" value="留言" >
<%
// out.print(user.getUsername());
session.setAttribute("user", user); %>
</form>
</body>
</html>
#message.jsp（留言页面）
<%@ page language="java" import="java.util.*,nmx.*,java.sql.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'message.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<jsp:useBean id="user" class="nmx.UserBean" scope="session" />
<% request.setCharacterEncoding("utf-8");
session.getAttribute("user");
session.setAttribute("Username", user);
%>
<form >
<textarea name="message" method="post"></textarea><br>
<input type="submit" value="提交" onclick="this.form.action = 'message.jsp'">
<input type="button" value="返回" onclick="window.location='main.jsp'">
</form>
<%
int id=0;
String message=request.getParameter("message");
if(message!=null){
Class.forName("com.mysql.jdbc.Driver");//记载数据库驱动，注册到驱动管理器
String url="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
String username="root";
String password="";
Connection conn=DriverManager.getConnection(url,username,password);
String sql1="insert into message values(?,?,?)";
String sql2="select id from message";
PreparedStatement ps1=conn.prepareStatement(sql1);
PreparedStatement ps2=conn.prepareStatement(sql2);
ResultSet rs=ps2.executeQuery();
while(rs.next()){
id=rs.getInt(1);
}
id+=1;
ps1.setInt(1,id);
ps1.setString(2,user.getUsername());
ps1.setString(3,message);
int rtn=ps1.executeUpdate();
ps1.close();
ps2.close();
conn.close();
%>
<%
if(rtn==1){
out.println("留言成功！");
}else{
out.println("留言失败！");
}
}%>
</body>
</html>
#error.jsp（登录失败页面）
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'error.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
用户名或密码错误，请<a href="login.jsp">重新登录</a>
</body>
</html>
#register.jsp（注册页面）
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'register.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<form name="form2" action="insertdata.jsp" method="post">
<table border="0">
<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>真实姓名：</td><td><input type="text" name="truename"></td></tr>
<tr><td>邮箱 ：</td><td><input type="text" name="email"></td></tr>
<tr><td colspan="2" align="center"> <input type="submit" name="reg" value="注册"> </td>
</table>
</form>
</body>
</html>
#insertdata.jsp（向数据库增加新用户）
<%@ page language="java" import="java.util.*" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.*"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
request.setCharacterEncoding("utf-8");
String Username=request.getParameter("username");
String Password=request.getParameter("password");
String Truename=request.getParameter("truename");
//out.print(Truename);
String Email=request.getParameter("email");
int id=0;
Class.forName("com.mysql.jdbc.Driver");//记载数据库驱动，注册到驱动管理器
String url="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8";
String username="root";
String password="";
Connection conn=DriverManager.getConnection(url,username,password);
String sql1="insert into user values(?,?,?,?,?)";
String sql2="select id from user";
PreparedStatement ps1=conn.prepareStatement(sql1);
PreparedStatement ps2=conn.prepareStatement(sql2);
ResultSet rs=ps2.executeQuery();
while(rs.next()){
id=rs.getInt(1);
}
id+=1;
ps1.setInt(1,id);
ps1.setString(2,Username);
ps1.setString(3,Password);
ps1.setString(4,Truename);
ps1.setString(5,Email);
int rtn=ps1.executeUpdate();
ps1.close();
ps2.close();
conn.close();
%>
<%
if(rtn==1){
response.sendRedirect("re_sucess.jsp");
}else{
response.sendRedirect("re_fail.jsp");
}
%>
</body>
</html>
#re_sucess(注册成功页面)
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 're_sucess.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
注册成功，请返回<a href="login.jsp">登录</a>
</body>
</html>
#re_fail.jsp（注册失败页面）
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 're_fail.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
注册失败，请重新<a href="register.jsp">注册</a>!
</body>
</html>
可以看出来，用jsp文件实现的话，整体会比较乱一些，因为数据的处理、页面的显示等都可以由jsp文件来完成，所以有的时候会分不清哪个文件是干什么工作的。但是jsp是比较简单而且全能的，还是应该好好学习。
代码里面其实有一些重复的地方，比如数据库的连接，可以专门写到一个类里面通过调用类来实现数据库的连接，减少代码的重复性。但是因为我太懒了，大家有兴趣的自行搞一下吧~