myeclipse实现Servlet实例(3) 通过继承HttpServlet接口实现

时间:2023-03-08 19:36:50
myeclipse实现Servlet实例(3) 通过继承HttpServlet接口实现

(1) 在软件公司 90%都是通过该方法开发.

//在HttpServlet 中,设计者对post 提交和 get提交分别处理 

 //回忆 <form action="提交给?" method="post|get"/>,默认是get

(2)小结 get 提交 和 post的提交的区别 

① 从安全看 get<post 因为get 会把提交的信息显示到地址栏 (提交密码时建议使用post)

② 从提交内容看 get<post get 一般不要大于2k, post理论上无限制,但是在实际开发中,建议不要大于64k 

③ 从速度看 get>post 

④ Get可以保留uri中的参数,利于收藏 

package com.tsinghua;





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 HelloHttp extends HttpServlet {





/* Constructor of the object. */

public HelloHttp() {

super();

}





/* Destruction of the servlet. <br>
*/

public void destroy() {

super.destroy();
// Just puts "destroy" string in log

// Put your code here

}





/**

* The doGet method of the servlet. <br>

* This method is called when a form has its tag value method equals to get.

*/

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

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.print("    This is ");

out.print(this.getClass());

out.println(", using the POST method");

out.println("  </BODY>");

out.println("</HTML>");

out.flush();

out.close();



}





/**

* The doPost method of the servlet. <br>

* This method is called when a form has its tag value method equals to post.

*/

public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {



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.print("    This is ");

out.print(this.getClass());

out.println(", using the POST method");

out.println("  </BODY>");

out.println("</HTML>");

out.flush();

out.close();

try{

PrintWriter out = response.getWriter();

out.println("Hello,Liu.http");

}

catch(Exception e){

e.printStackTrace();

}

}





/*Initialization of the servlet. <br>
*/

public void init() throws ServletException {

// Put your code here

}





}