//实现简单的登陆系统
package com.tsinghua;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class Login extends HttpServlet
{
public void doGet(HttpServletRequest req, HttpServletResponse res)
{
try{
res.setContentType("text/html;charset=GBk"); //这个是解决中文乱码的问题
PrintWriter pw = res.getWriter();
pw.println("<html>");
pw.println("<body>");
pw.println("<h1>登陆界面</h1>");
pw.println("<form action=LoginC1 method=post>");
pw.println("用户名:<input type=text name=usrename><br>");
pw.println("密码:<input type=password name=passwd><br>");
pw.println("<input type=submit value=loing><br>");
pw.println("</form>");
pw.println("</body>");
pw.println("</html>");
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
package com.tsinghua;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class LoginC1 extends HttpServlet
{
public void doGet(HttpServletRequest req, HttpServletResponse res)
{
try{
String u = req.getParameter("usrename");
String p = req.getParameter("passwd");
if (u.equals("sp")&&p.equals("123")){
res.sendRedirect("LoginC2?uname="+u);
}else{
res.sendRedirect("Login");
}
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
public void doPost(HttpServletRequest req, HttpServletResponse res)
{
this.doGet( req, res);
}
}//这个不能少,
//显示跳转的登陆信息。
package com.tsinghua;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class LoginC2 extends HttpServlet
{
public void doGet(HttpServletRequest req, HttpServletResponse res)
{
String u=req.getParameter("uname");
try{
PrintWriter pw = res.getWriter();
pw.println("wellcome"+u);
}
catch(Exception ex)
{
ex.printStackTrace();
}
}
}
总结:doGet(HttpServletRequest req, HttpServletResponse res)//req 是获取字符串,res是显示字符串。doGet方法必须要和doPost方法同时使用,漏掉露面的网页部署上会显示路径报错,错误
string u = req.getParameter("usrename");
string p = req.getParameter("passwd");//res.sendRedirect("wel?nuame="+u+"&upasswd"+p)