Tomcat-Servlet(一)

最新推荐文章于 2025-04-14 08:00:00 发布

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本文介绍了一种通过实现Servlet接口来创建Web应用的方法。具体步骤包括配置index.jsp页面以供用户输入，定义web.xml文件来注册Servlet，并实现Servlet接口以响应HTTP请求。文中还展示了如何在控制台打印初始化参数及请求信息。

Servlet的实现方式一：实现Servlet接口

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/myServlet1" 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>myServlet</servlet-name>
  	<servlet-class>com.demo.servlet.MyServlet</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>myServlet</servlet-name>
  	<url-pattern>/myServlet</url-pattern>
  </servlet-mapping>
</web-app>

3、实现Servlet接口

package com.demo.servlet;

import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class MyServlet implements Servlet{

	@Override
	public void destroy() {
		System.out.println("***Servlet destoryMethod invoke");
	}

	@Override
	public ServletConfig getServletConfig() {
		return null;
	}

	@Override
	public String getServletInfo() {
		return null;
	}

	@Override
	public void init(ServletConfig arg0) throws ServletException {
		ServletContext servletContext = arg0.getServletContext();
		System.out.println("ServletContext："+servletContext);
		String servletName = arg0.getServletName();
		System.out.println("ServletName："+servletName);
		String initParameter = arg0.getInitParameter("myServlet1");
		System.out.println("InitParameter: "+initParameter);
		Enumeration<String> initParameterNames = arg0.getInitParameterNames();
		while (initParameterNames.hasMoreElements()) {
			String initParameterName = (String)initParameterNames.nextElement();
			String initParameterValue=arg0.getInitParameter(initParameterName);
			System.out.println("initParameterNames: "+initParameterName);
			System.out.println("inirPatameterValue: "+initParameterValue);
			
		}
	}

	@Override
	public void service(ServletRequest arg0, ServletResponse arg1) throws ServletException, IOException {
		System.out.println("***Servlet ServiceMethod invoke");
		System.out.println("***ServletRequest"+arg0);
		System.out.println("***ServletResponse"+arg0);
	}

}

4、页面请求

5、控制台打印接收请求

***Servlet initMethod invoke
ServletContext：org.apache.catalina.core.ApplicationContextFacade@783b3f7b
ServletName：myServlet
InitParameter: myServletValue1
initParameterNames: myServlet2
inirPatameterValue: myServletValue2
initParameterNames: myServlet1
inirPatameterValue: myServletValue1

***Servlet serviceMethod invoke
***ServletRequestorg.apache.catalina.connector.RequestFacade@6d8dbc42
***ServletResponseorg.apache.catalina.connector.RequestFacade@6d8dbc42