Servlet

• 文章目录
• 一、Servlet快速入门
• 二、Servlet的生命周期
• 三、servlet方法
• 四、servlet体系结构
• 五、servlet urlPattern配置
• 六、XML配置方式编写servlet

案例：

//servlet依赖坐标

    
      javax.servlet
      javax.servlet-api
      3.1.0
      provided
    
  


package com.study.web;

import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import java.io.IOException;
@WebServlet("/demo1")
public class ServletDemo1 implements Servlet {
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("Hello!");
    }

    @Override
    public ServletConfig getServletConfig() {
        return null;
    }

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {

    }

    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public void destroy() {

    }
}

在控制台会打印Hello!。

案例：

package com.study.web;

import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import java.io.IOException;
@WebServlet("/demo2")
public class ServletDemo2 implements Servlet {
    //第一次访问servlet的时候调用，该方法只调用一次。
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("init.......");

    }
    //每次访问Servlet时都会被调用
    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("Hello Service");
    }
    //释放内存或容器关闭时调用，只调用一次
    @Override
    public void destroy() {
        System.out.println("destroy....");

    }
    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public ServletConfig getServletConfig() {
        return null;
    }
}

案例：

    
    



    





package com.study.web;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
@WebServlet("/demo3")
public class ServletDemo3 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("doGet...");
    }

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