二、分清假设、估计和偏差
2026/1/16 20:03:33
<packaging>war</packaging><dependencies><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>4.0.1</version><scope>provided</scope></dependency></dependencies><build><plugins><plugin><groupId>org.apache.tomcat.maven</groupId><artifactId>tomcat7-maven-plugin</artifactId><version>2.2</version><configuration><port>8087</port></configuration></plugin></plugins></build>
完整pm.xml文件
<?xmlversion="1.0"encoding="UTF-8"?><projectxmlns="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.gaofeng</groupId><artifactId>servlet_demo_01</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><properties><maven.compiler.source>17</maven.compiler.source><maven.compiler.target>17</maven.compiler.target><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>4.0.1</version><scope>provided</scope></dependency></dependencies><build><plugins><plugin><groupId>org.apache.tomcat.maven</groupId><artifactId>tomcat7-maven-plugin</artifactId><version>2.2</version><configuration><port>8087</port></configuration></plugin></plugins></build></project>ServletDemo01.java
packagecom.gaofeng;importjavax.servlet.*;importjavax.servlet.annotation.WebServlet;// 添加此行importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importjava.io.IOException;importjava.io.PrintWriter;@WebServlet(urlPatterns="/demo1")publicclassServletDemo01implementsServlet{@Overridepublicvoidinit(ServletConfigservletConfig)throwsServletException{System.out.println("init...");}@OverridepublicServletConfiggetServletConfig(){returnnull;}@Overridepublicvoidservice(ServletRequestservletRequest,ServletResponseservletResponse)throwsServletException,IOException{System.out.println("service...");HttpServletRequestrequest=(HttpServletRequest)servletRequest;HttpServletResponseresponse=(HttpServletResponse)servletResponse;Stringusername=request.getParameter("username");System.out.println("username:"+username);response.setContentType("text/html;charset=utf-8");PrintWriterwriter=response.getWriter();if(username.equals("admin")){writer.println("<h1>Hello, "+username+"</h1>");}else{writer.println("<h1>您没有权限访问此页面</h1>");}}@OverridepublicStringgetServletInfo(){return"";}@Overridepublicvoiddestroy(){}}