创建您的第一个servlet

在本教程中，我们将学习如何使用Servlet创建非常基本的Web应用程序。

Servlet是一类，扩展了服务器拦截和响应传入请求的功能。 Servlet是一个Web组件，可在服务器上进行编写，构建和部署，以创建动态Web页面。

首先，我们需要在系统中安装Eclipse IDE，并按照下面列出的步骤进行操作。

1.打开Eclipse并创建一个动态Web项目 。

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2.指定项目详细信息，如下所示，然后单击“下一步”。

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3.设置Web模块详细信息并生成web.xml。

4.单击完成。右键单击Servlet Demo项目，然后单击“转换为Maven项目”。

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而已。基本设置已完成。

验证web.xml文件如下所示。

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>ServletDemo</display-name><welcome-file-list><welcome-file>hello.jsp</welcome-file></welcome-file-list><servlet><description></description><display-name>DemoServlet</display-name><servlet-name>demo</servlet-name><servlet-class>com.jcombat.sample.DemoServlet</servlet-class></servlet><servlet-mapping><servlet-name>demo</servlet-name><url-pattern>/demo</url-pattern></servlet-mapping>
</web-app>

在与web.xml中指定的相同的包中创建DemoServlet类。

DemoServlet.java

package com.jcombat.sample;import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class DemoServlet extends HttpServlet {private static final long serialVersionUID = 1L;/*** @see HttpServlet#HttpServlet()*/public DemoServlet() {super();}/*** @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)*/protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}/*** @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)*/protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {request.getRequestDispatcher("/Test.jsp").forward(request, response);}}

现在，让我们在Web Content下创建两个JSP文件– hello.jsp和test.jsp 。

hello.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1"><title>Hello World</title></head><body>Welcome to landing page</body>
</html>

Test.jsp

@ page language="java" contentType="text/html; charset=ISO-8859-1"pageEncoding="ISO-8859-1"%>
<!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=ISO-8859-1"><title>Demo Page</title></head><body>Welcome to demo page</body>
</html>

接下来，将pom.xml与以下提到的内容进行比较和验证–

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><groupId>com.jcombat.sample</groupId><artifactId>ServletDemo</artifactId><version>0.0.1-SNAPSHOT</version><packaging>war</packaging><name>Servlet with Maven Demo</name><description>Servlet with Maven & Tomcat Demo</description><dependencies><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.0.1</version><scope>provided</scope></dependency></dependencies><build><sourceDirectory>src</sourceDirectory><plugins><plugin><artifactId>maven-war-plugin</artifactId><version>2.4</version><configuration><warSourceDirectory>WebContent</warSourceDirectory><failOnMissingWebXml>false</failOnMissingWebXml></configuration></plugin><plugin><artifactId>maven-compiler-plugin</artifactId><configuration><source>1.7</source><target>1.7</target></configuration></plugin></plugins></build>
</project>