Java中Servlet的生命周期详解

                       ┌─────────┐
┌─────────┐            │░░░░░░░░░│
│O ░░░░░░░│            ├─────────┤
├─────────┤            │░░░░░░░░░│
│         │            ├─────────┤
│         │            │░░░░░░░░░│
└─────────┘            └─────────┘
     │      request 1       │
     │─────────────────────>│
     │      request 2       │
     │─────────────────────>│
     │      response 1      │
     │<─────────────────────│
     │      request 3       │
     │─────────────────────>│
     │      response 3      │
     │<─────────────────────│
     │      response 2      │
     │<─────────────────────│
     ▼                      ▼

// WebServlet注解表示这是一个Servlet，并映射到地址 hello.do
@WebServlet(urlPatterns = "/hello.do")
public class HelloServlet extends HttpServlet {
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        // 设置响应类型:
 
        resp.setContentType("text/html");
        // 获取输出流:
 
        PrintWriter pw = resp.getWriter();
        // 写入响应:
 
        pw.write("<h1>Hello, world!</h1>");
        // 最后不要忘记flush强制输出:
 
        pw.flush();
    }
}

package com.my.hyz.web.servlet;
 
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;
//@WebServlet("/home.do")
public class HomeServlet extends HttpServlet {

	public HomeServlet() {
		System.out.println("实例化");
	}
	@Override
	public void init() throws ServletException {
		System.out.println("初始化");
		//super.init();
	}

	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("调用Service实例");
	}

	@Override
	public void destroy() {
		System.out.println("销毁咯！！！！");
	}
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub
		System.out.println("哎呦get到了"+this.hashCode());
	}
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		System.out.println("哎呦post到了");
	}
}