第一个登录界面web应用

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1.最基本的web登陆界面应用框架
这里写图片描述
在此案列中运用的是sendRedirect方法传递信息
2.对应每个流程写相应类
a.登陆界面编写

package com.myfirstwebLogin;import java.io.PrintWriter;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class Login extends HttpServlet{    public void doGet(HttpServletRequest req,HttpServletResponse res){        try{            //中文乱码            res.setContentType("text/html;charset=utf-8");            PrintWriter pw=res.getWriter();            //返回登录页面            pw.println("<html>");            pw.println("<body>");            pw.println("<h1>登录界面</h1>");            //action后面接跳转的url            pw.println("<form action=logincheck method=post>");            pw.println("用户名:<input type=text name=username><br>");            pw.println("密   码:<input type=password name=password><br>");            pw.println("<input type=submit value=login><br>");            pw.println("</form>");            pw.println("</body>");            pw.println("</html>");        }        catch(Exception ex){            ex.printStackTrace();        }    }    public void doPost(HttpServletRequest req,HttpServletResponse res){        this.doGet(req, res);    }}

b.用户信息核对

package com.myfirstwebLogin;import java.io.PrintWriter;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class LoginCheck extends HttpServlet{    public void doGet(HttpServletRequest req,HttpServletResponse res){        try{            //接收用户名和密码            String username=req.getParameter("username");            String password=req.getParameter("password");            if(username.equals("tpx")&&password.equals("123456")){                //传递给welcome页面username                res.sendRedirect("welcome?username="+username);            }            else{                //跳转的url                res.sendRedirect("login");            }        }        catch(Exception ex){            ex.printStackTrace();        }    }    public void doPost(HttpServletRequest req,HttpServletResponse res){        this.doGet(req, res);    }}

c.登陆成功页面

package com.myfirstwebLogin;import java.io.PrintWriter;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class Welcome extends HttpServlet{    public void doGet(HttpServletRequest req,HttpServletResponse res){        //业务逻辑处理        try{            //接收LoginCheck中的username            String username=req.getParameter("username");            PrintWriter pw=res.getWriter();            pw.println("Welcome"+"  "+username);        }catch(Exception ex){            ex.printStackTrace();        }    }    //处理post请求    public void doPost(HttpServletRequest req,HttpServletResponse res){        this.doGet(req, res);    }}

3配置到服务器
对应每个类都要配置在web.xml中
详见web环境设置
4效果如下
登陆界面
登陆成功

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