3.3.1实现Servlet

FirstServlet.java

package com.helloweenvsfei.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class FirstServlet extends HttpServlet {
    
    public void doGet(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,IOException{
        this.log("执行doGet方法...");
        this.execute(request,response);
    }
    public void doPost(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,IOException{
        this.log("执行doPost方法...");
        this.execute(request,response);
    }
    @Override
    public long getLastModified(HttpServletRequest request){
        this.log("执行getLastModified方法");
        return -1;
        }
    private void execute(HttpServletRequest request,HttpServletResponse response)
    throws ServletException,IOException{
        response.setCharacterEncoding("UTF-8");
        request.setCharacterEncoding("UTF-8");
        String requestURI=request.getRequestURI();
        String method=request.getMethod();
        String param=request.getParameter("param");
        
        response.setContentType("text/html");
        PrintWriter out=response.getWriter();
        out.println("<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">");
        out.println("<HTML>");
        out.println("<HEAD><TITLE>A Servlet</TITLE></HEAD>");
        out.println("<BODY>");
        out.println("以"+method+"方式访问该页面。取到的param参数为:"+param+"<br/>");
        out.println("<form action='"+requestURI+"'method='get'><input type='text'name='param'value='param string'><input type='submit'value='以GET方式查询页面"+requestURI+"'></form>");
        out.println("<form action='"+requestURI+"'method='post'><input type='text'name='param'value='param string'><input type='submit'value='以POST方式查询页面"+requestURI+"'></form>");
        out.println("<script>document.write('本页面最后更新时间:'+document.lastModified);</script>");
        out.println("</BODY>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
    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_2_5.xsd">
  <servlet>
  <servlet-name> FirstServlet</servlet-name>
  <servlet-class>com.helloweenvsfei.servlet.FirstServlet</servlet-class>
  <init-param>
  <param-name>message</param-name>
  <param-value>welcome to FirstServlet</param-value>
  </init-param>
  <init-param>
  <param-name>encoding</param-name>
  <param-value>utf-8</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>FirstServlet</servlet-name>
<url-pattern>/servlet/FirstServlet</url-pattern>
<url-pattern>/servlet/FirstServlet.asp</url-pattern>
<url-pattern>/servlet/FirstServlet.php</url-pattern>
<url-pattern>/servlet/FirstServlet.jsp</url-pattern>
<url-pattern>/servlet/FirstServlet.aspx</url-pattern>
</servlet-mapping>
</web-app>
原文地址:https://www.cnblogs.com/ys-wuhan/p/5892821.html