Tomcat-Servlet(二)

Java Web登录示例

最新推荐文章于 2025-04-14 08:00:00 发布

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本文介绍了一个简单的Java Web用户登录示例，包括index.jsp页面、web.xml配置文件、MyServlet2处理类等内容。示例展示了如何通过GET方式提交表单，并在Servlet中获取用户名和密码。

1、index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
    <div align="center">
	<h4>用户登录</h4>
	<form action="http://localhost:8080/DemoServlet/myServlet2" method="get">
		姓名：<input type="text" name="userName" align="right"><br>
		密码：<input type="password" name="passWord" align="right"><br>
		<span style="">
			<input type="submit" value="登录">
			<input type="submit" value="忘记密码">
		</span>
	</form>
    </div>
</body>
</html>

2、web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>DemoServlet</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
  	<servlet-name>myServlet2</servlet-name>
  	<servlet-class>com.demo.servlet.MyServlet2</servlet-class>
  	<init-param>
  		<param-name>myServlet1</param-name>
  		<param-value>myServletValue1</param-value>
  	</init-param>
  	<init-param>
  		<param-name>myServlet2</param-name>
  		<param-value>myServletValue2</param-value>
  	</init-param>
  </servlet>
  <servlet-mapping>
  	<servlet-name>myServlet2</servlet-name>
  	<url-pattern>/myServlet2</url-pattern>
  </servlet-mapping>
</web-app>

3、继承HttpServlet

package com.demo.servlet;

import java.io.IOException;
import java.util.Locale;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MyServlet2 extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	
	 protected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{
		 
		 String characterEncoding = req.getCharacterEncoding();
		 System.out.println("***CharacterEncoding: "+characterEncoding);
		 String contentType = req.getContentType();
		 System.out.println("***ContentType: "+contentType);
		 int contentLength = req.getContentLength();
		 System.out.println("***ContentLength: "+contentLength);
		 
		 String localAddr = req.getLocalAddr();
		 System.out.println("***LocalAddr: "+localAddr);
		 Locale locale = req.getLocale();
		 System.out.println("***Locale： "+locale);
		 String localName = req.getLocalName();
		 System.out.println("***LocalName: "+localName);
		 int localPort = req.getLocalPort();
		 System.out.println("***LocalPort: "+localPort);
		 
		 ServletContext servletContext = req.getServletContext();
		 System.out.println("***servletContext: "+servletContext);
		 String contextPath = req.getContextPath();
		 System.out.println("***ContextPath: "+contextPath);
		 
		 String protocol = req.getProtocol();
		 System.out.println("***Protocol: "+protocol);
		 String method = req.getMethod();
		 System.out.println("***Method: "+method);
		 StringBuffer requestURL = req.getRequestURL();
		 System.out.println("***requestURL: "+requestURL);
		 String requestURI = req.getRequestURI();
		 System.out.println("***requestURI: "+requestURI);
		 String queryString = req.getQueryString();
		 System.out.println("***QueryString: "+queryString);
		 
		 String serverName = req.getServerName();
		 System.out.println("***ServerName: "+serverName);
		 String scheme = req.getScheme();
		 System.out.println("***Scheme: "+scheme);
		 int serverPort = req.getServerPort();
		 System.out.println("***ServerPort: "+serverPort);
		 String servletPath = req.getServletPath();
		 System.out.println("***ServletPath: "+servletPath);
		
		 String userName = req.getParameter("userName");
		 System.out.println("***userName: "+userName);
		 String password = req.getParameter("passWord");
		 System.out.println("***password: "+password);
		 
		 
	 }
	 
	 protected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException{
		 
	 }

}

4、页面请求

5、后台接收请求打印

***CharacterEncoding: null
***ContentType: null
***ContentLength: -1
***LocalAddr: 0:0:0:0:0:0:0:1
***Locale： zh_CN
***LocalName: 0:0:0:0:0:0:0:1
***LocalPort: 8080
***servletContext: org.apache.catalina.core.ApplicationContextFacade@4867dbd4
***ContextPath: /DemoServlet
***Protocol: HTTP/1.1
***Method: GET
***requestURL: http://localhost:8080/DemoServlet/myServlet2
***requestURI: /DemoServlet/myServlet2
***QueryString: userName=admin&passWord=admin
***ServerName: localhost
***Scheme: http
***ServerPort: 8080
***ServletPath: /myServlet2
***userName: admin
***password: admin