Servlet实现登录表单示例 _登录表单

【Servlet实现登录表单示例】在这里, 我们将创建一个简单的示例, 以使用servlet创建登录表单。我们已经使用oracle10g作为数据库。该应用程序需要5个文件。

index.html
FirstServlet.java
LoginDao.java
SecondServlet.java
web.xml

你必须创建带有名称和传递字段的表userreg。而且, 它必须包含一些数据。该表应为：

create table userreg(name varchar2(40), pass varchar2(40));

index.html

< form action="servlet1" method="post"> Name:< input type="text" name="username"/> < br/> < br/> Password:< input type="password" name="userpass"/> < br/> < br/> < input type="submit" value="http://www.srcmini.com/login"/> < /form>

FirstServlet.java

import java.io.IOException; import java.io.PrintWriter; import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class FirstServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String n=request.getParameter("username"); String p=request.getParameter("userpass"); if(LoginDao.validate(n, p)){ RequestDispatcher rd=request.getRequestDispatcher("servlet2"); rd.forward(request, response); } else{ out.print("Sorry username or password error"); RequestDispatcher rd=request.getRequestDispatcher("index.html"); rd.include(request, response); } out.close(); } }

LoginDao.java

import java.sql.*; public class LoginDao { public static boolean validate(String name, String pass){ boolean status=false; try{ Class.forName("oracle.jdbc.driver.OracleDriver"); Connection con=DriverManager.getConnection( "jdbc:oracle:thin:@localhost:1521:xe", "system", "oracle"); PreparedStatement ps=con.prepareStatement( "select * from userreg where name=? and pass=?"); ps.setString(1, name); ps.setString(2, pass); ResultSet rs=ps.executeQuery(); status=rs.next(); }catch(Exception e){System.out.println(e); } return status; } }

WelcomeServlet.java

import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class WelcomeServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String n=request.getParameter("username"); out.print("Welcome "+n); out.close(); }}

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