实在不明白跳转失败，servlet,初学者 (via TranXcode)
看的韩的视频
基本写的都一样，从登录//Login，到验证//LoginCl，成功//Wel
package com.zgd;
import javax.servlet.*;
import java.io.*;
import javax.servlet.http.*;
public class Login extends HttpServlet {
// get
public void doGet(HttpServletRequest req,HttpServletResponse res){
System.out.println(" service ");
res.setContentType("text/html; charset=gbk");
try {
PrintWriter pw=res.getWriter();
pw.println(" <html>");
pw.println(" <title>");
pw.println("学生登录");
pw.println(" </title>");
pw.println(" <body>");
pw.println(" <H1>登录界面 </H1>");
pw.println(" <form action=LoginCl,method=post>");
pw.println("用户名： <input type=text name=username> <br>");
pw.println("密码： <input type=password name=passwd> <br>");
pw.println(" <input type=submit value=Login> <br> ");
pw.println(" </form>");
pw.println(" </body>");
pw.println(" </html>");
}
catch(Exception e){
e.printStackTrace();
}
}
public void doPost(HttpServletRequest req,HttpServletResponse res){
doGet(req,res);
}
}
package com.zgd;
import javax.servlet.*;
import java.io.*;
import javax.servlet.http.*;
public class LoginCl extends HttpServlet {
// get
public void doGet(HttpServletRequest req,HttpServletResponse res){
res.setContentType("text/html; charset=gbk");
try {
PrintWriter pw=res.getWriter();
pw.println(" <html> <body> <h1>你来到了 验证界面 </h1> </body> </html>");
String u=req.getParameter("username");
String p=req.getParameter("passwd");
if(u.equals("xll")&&p.equals("xll")){
res.sendRedirect("Wel");
} else {
res.sendRedirect("Login");//to URL
}
}
catch(Exception e){
e.printStackTrace();
}
}
public void doPost(HttpServletRequest req,HttpServletResponse res){
this.doGet(req,res);
}
}
package com.zgd;
import javax.servlet.*;
import java.io.*;
import javax.servlet.http.*;
public class Wel extends HttpServlet {
// get
public void doGet(HttpServletRequest req,HttpServletResponse res){
System.out.println(" service ");
try {
PrintWriter pw=res.getWriter();
pw.println("WEL COME ,U");
}
catch(Exception e){
e.printStackTrace();
}
}
public void doPost(HttpServletRequest req,HttpServletResponse res){
doGet(req,res);
}
}
<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<servlet>
<servlet-name>Login </servlet-name>
<servlet-class>com.zgd.Login </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Login </servlet-name>
<url-pattern>/Login </url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>Wel </servlet-name>
<servlet-class>com.zgd.Wel </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Wel </servlet-name>
<url-pattern>/Wel </url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>Loginlala </servlet-name>
<servlet-class>com.zgd.LoginCl </servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Loginlala </servlet-name>
<url-pattern>/LoginCl </url-pattern>
</servlet-mapping>
</web-app>
