Servlet学习笔记(四)-----使用Servlet处理用户注册和登陆

1. 首先是login.html页面，代码如下：

<html>

<body>

function valid(form)

{

if(form.username.value.length==0)

{

alert("Please enter username!");

form.username.focus();

return false;

}

if(form.pass.value.length==0)

{

alert("Please enter password!");

form.pass.focus();

return false;

}

</script>

<tr>

<td>用户名：

</font>

<br>

密码：

<br>

<option class=inpt value="1">随心DIY</option>

</select>

</td>

</tr>

</table>

</form>

</body>

</html>

2. RegistorForm.html页面，代码如下：

<html>

function valid(form)

{

if(form.username.value.length==0)

{

alert("The user name cannot be left black!");

form.username.focus();

return false;

}

if(form.pass.value.length==0)

{

alert("The pass cannot be left black!");

form.pass.focus();

return false;

}

if(form.address.value.length==0)

{

alert("The Address cannot be left black!");

form.address.focus();

return false;

}

if(form.acctype.value.length==0)

{

alert("The Account Type cannot be left black!");

form.acctype.focus();

return false;

}

if(form.income.value.length==0)

{

alert("The Annual Income cannot be left black!");

form.income.focus();

return false;

}

if(form.phonenumber.value.length==0)

{

alert("The Phone Number cannot be left black!");

form.phonenumber.focus();

return false;

}

</script>

<tr>

</tr>

<tr>

</tr>

<tr>

</tr>

<tr>

</tr>

<tr>

</tr>

<tr>

<tr>

</tr>

</table>

</center>

</form>

</body>

</html>

3. LoginForm.java代码如下：

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;

import java.sql.*;

///import javax.sql.*;

public class LoginForm extends HttpServlet

{

Connection dbcon;

protected void doPost(HttpServletRequest req,

HttpServletResponse resp)

throws ServletException,

java.io.IOException

{

try

{

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

dbcon=DriverManager.getConnection("jdbc:odbc:test","sa","");

System.out.println("Connection established");

}

catch(Exception e)

{

System.out.println("Database not found!");

}

String username=req.getParameter("username").trim();

String pass=req.getParameter("pass").trim();

resp.setContentType("text/html");

PrintWriter out=resp.getWriter();

try

{

PreparedStatement stat=dbcon.prepareStatement(

"select * from UserData where username=? and pass=?");

stat.setString(1,username);

stat.setString(2,pass);

ResultSet result=stat.executeQuery();

if(result.next())

{

out.println("<html><body bgcolor=pink>");

out.println(" Login Successful");

out.println("<br><br>");

out.println("</body></html>");

}

else

{

out.println("<html><body bgcolor=pink>");

out.println(" Login ERROR");

out.println("<br><br>");

out.println("</body></html>");

}

catch(Exception e)

{

e.toString();

}

try

{

dbcon.close();

}

catch(Exception e)

{

System.out.println(e.toString());

}

4. RegistorForm.java代码如下：

import javax.servlet.*;

import javax.servlet.http.*;

import java.io.*;

import java.sql.*;

///import javax.sql.*;

public class RegistorForm extends HttpServlet

{

Connection dbcon;

protected void doPost(HttpServletRequest req,

HttpServletResponse resp)

throws ServletException,

java.io.IOException

{

try

{

Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");

dbcon=DriverManager.getConnection("jdbc:odbc:test","sa","");

System.out.println("Connection established");

}

catch(Exception e)

{

System.out.println("Database not found!");

}

resp.setContentType("text/html");

PrintWriter out=resp.getWriter();

String firstname=req.getParameter("username");

String lastname=req.getParameter("pass");

String address=req.getParameter("address");

String acctype=req.getParameter("acctype");

double income=Double.parseDouble(req.getParameter("income"));

int phonenumber=Integer.parseInt(req.getParameter("phonenumber"));

int rows=0;

try

{

PreparedStatement stat=dbcon.prepareStatement(

"insert UserData values(?,?,?,?,?,?)");

stat.setString(1,firstname);

stat.setString(2,lastname);

stat.setString(3,address);

stat.setString(4,acctype);

stat.setDouble(5,income);

stat.setInt(6,phonenumber);

rows=stat.executeUpdate();

}

catch(Exception e)

{

System.out.println(e.toString());

}

if(rows==0)

{

System.out.println("Error Insert");

}

else

{

System.out.println("Successful Insert");

}

String regno=new String("1111");

try

{

PreparedStatement stat=dbcon.prepareStatement(

"select max(UserID) from UserData");

ResultSet result=stat.executeQuery();

result.next();

regno=result.getString(1);

}

catch(Exception e)

{

e.toString();

}

out.println("<html><body bgcolor=pink>");

out.println("Thank you");

out.println("<br><br>");

out.println("your registration ID is :<b>"+regno+"</b>");

out.println("<br>");

out.println("</body></html>");

try

{

dbcon.close();

}

catch(Exception e)

{

System.out.println(e.toString());

}

5. 数据库UserData.sql代码如下:

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[UserData]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)

drop table [dbo].[UserData]

CREATE TABLE [dbo].[UserData] (

[UserID] [int] IDENTITY (1, 1) NOT NULL ,

[username] [char] (10) COLLATE Chinese_PRC_CI_AS NULL ,

[pass] [char] (10) COLLATE Chinese_PRC_CI_AS NULL ,

[address] [char] (10) COLLATE Chinese_PRC_CI_AS NULL ,

[acctype] [char] (10) COLLATE Chinese_PRC_CI_AS NULL ,

[income] [money] NULL ,

[phonenumber] [int] NULL

) ON [PRIMARY]

6. 因为有两个Servlet,所以需要新建两个Web Component,我把它们命名为web和web1

7. J2ee服务器启动后,客户端输入http://127.0.0.1:8000/web/Login.htm