5_3.0servlet中修改init默认启动

最新推荐文章于 2024-11-16 21:07:02 发布

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本文深入探讨了Servlet3.0的特性，特别是如何通过注解@WebServlet的loadOnStartup属性实现Servlet初始化方法init()的预加载，以及doGet和doPost方法的具体实现。同时，提供了index.jsp页面的示例代码，展示了如何通过超链接和表单触发这两种请求。

Demo_01.java

package study;

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/*
 * 将init()方法重默认的第一次访问servlet时调用改成开始加载服务时默认调用
 * 在servlet3.0
 */
@WebServlet(value="/Demo_01",loadOnStartup=1)
//其中的"1"意思是当有多个<servlet>时,执行的先后顺序
public class Demo_01 extends HttpServlet {
	private static final long serialVersionUID = 1L;
	public void init() throws ServletException {
		System.out.println("3.0init方法");
	}

	public void destroy() {
		System.out.println("3.0destroy方法");
	}
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		System.out.println("3.0service方法的具体实现doget");
	}
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		System.out.println("3.0service方法的具体实现dopost");
	}
}

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>
	<a href="Demo_01">doGet</a><!-- 超链接都是get方式 -->
	<form action="Demo_01" method="post">
		<input type="submit" value="dopost">
	</form>
</body>
</html>