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Servlet登陆功能的实现

2024-07-20 07:41:22   221人阅读

（1）创建动态的Login页面

//登陆界面
package com.lc;

import javax.servlet.http.*;

import java.io.*;

public class Login extends HttpServlet{
	
	public void doGet(HttpServletRequest req,HttpServletResponse res){
		
		//业务逻辑
		try{
			//解决中文乱码
			res.setContentType("text/html;charset=gbk");
			
			PrintWriter pw = res.getWriter();
			//返回登陆界面
			pw.println("<html>");
			pw.println("<body>");			
			
			pw.println("<h1>用户登录</h1>");
			pw.println("<form action=logincl method=post>");  //action的是servlet的url
			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=http://www.mamicode.com/loing>
");>（2）创建接受Login的servlet
//登陆界面
package com.lc;

import javax.servlet.http.*;

import java.io.*;

public class Logincl extends HttpServlet{
	
	public void doGet(HttpServletRequest req,HttpServletResponse res){
		
		//业务逻辑
		try{
			//解决中文乱码
			
			//接受用户名和密码
			String u = req.getParameter("username");
			String p = req.getParameter("passwd");
			//验证
			if(u.equals("lc") && p.equals("123"))
			{
				//合法的情况 跳转到Welcome
				res.sendRedirect("welcome");//这里跳转的仍是servlet的url
			}
			else
			{
				//不合法的情况
				//跳转
				res.sendRedirect("login");//跳转的是要到servlet的url
			}
		
		}
		catch(Exception ex){
			ex.printStackTrace();
		}
	}
	
	public void doPost(HttpServletRequest req,HttpServletResponse res){
		this.doGet(req,res);
	}
}

（3）登陆成功要跳转的welcome页面
//登陆界面
package com.tsinghua;

import javax.servlet.http.*;

import java.io.*;

public class Welcome extends HttpServlet{
	
	public void doGet(HttpServletRequest req,HttpServletResponse res){
		
		//业务逻辑
		try{
			//解决中文乱码
			res.setContentType("text/html;charset=gbk");
			
			PrintWriter pw = res.getWriter();
		
			pw.println("hello welcome！");
			
		}
		catch(Exception ex){
			ex.printStackTrace();
		}
	}
	
	public void doPost(HttpServletRequest req,HttpServletResponse res){
		this.doGet(req,res);
	}
}

（4）配置文件web.xml的编写
<?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_3_0.xsd"
  version="3.0"
  metadata-complete="true">

  <display-name>Welcome to Tomcat</display-name>
  <description>
     Welcome to Tomcat
  </description>
  
<!--JSP servlet mappings starts-->


  <servlet>
    <servlet-name>Login</servlet-name>
    <servlet-class>com.lc.Login</servlet-class>
  </servlet>
   <servlet-mapping>
    <servlet-name>Login</servlet-name>
    <url-pattern>/login</url-pattern>
  </servlet-mapping>

  <servlet>
    <servlet-name>Logincl</servlet-name>
    <servlet-class>com.<span style="font-family:Arial, Helvetica, sans-serif;">lc</span>.Logincl</servlet-class>
  </servlet>
   <servlet-mapping>
    <servlet-name>Logincl</servlet-name>
    <url-pattern>/logincl</url-pattern>
  </servlet-mapping>

  <servlet>
    <servlet-name>Welcome</servlet-name>
    <servlet-class>com.lc.Welcome</servlet-class>
  </servlet>
   <servlet-mapping>
    <servlet-name>Welcome</servlet-name>
    <url-pattern>/welcome</url-pattern>
  </servlet-mapping>

<!--JSP servlet mappings end-->
</web-app>


（5）运行结果：




Servlet登陆功能的实现


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