package cn.itcast.web.servletcontext;

import javax.servlet.ServletContext;
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;

/**
 * @author 旗木五五开
 * @create 2020-03-08 8:48
 */
@WebServlet("/servletContextDemo1")
public class ServletContextDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        servletContext获取
        ServletContext context1 = request.getServletContext();
        ServletContext context2 = this.getServletContext();
        System.out.println(context1==context2);//true
        System.out.println(context1);
        System.out.println(context2);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request,response);
    }
}

package cn.itcast.web.servletcontext;

import javax.servlet.ServletContext;
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;

/**
 * @author 旗木五五开
 * @create 2020-03-08 9:30
 */
@WebServlet("/servletContextDemo2")
public class ServletContextDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        1.通过 HttpServlet 获取
        ServletContext context = this.getServletContext();
//        2.定义文件名称。以后是通过对应的文件动态的获取
        String filename="a.jpg";
//        3.获取mime类型
        String mimeType = context.getMimeType(filename);
        System.out.println(mimeType);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request,response);
    }
}

package cn.itcast.web.servletcontext;

import javax.servlet.ServletContext;
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;

/**
 * @author 旗木五五开
 * @create 2020-03-08 9:45
 */
@WebServlet("/servletContextDemo3")
public class ServletContextDemo3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        1.通过 HttpServlet 获取
        ServletContext context = this.getServletContext();
//        2.设置数据
        context.setAttribute("msg","haha");
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request,response);
    }
}

package cn.itcast.web.servletcontext;

import javax.servlet.ServletContext;
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;

/**
 * @author 旗木五五开
 * @create 2020-03-08 9:47
 */
@WebServlet("/servletContextDemo4")
public class ServletContextDemo4 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        1.通过 HttpServlet 获取
        ServletContext context = this.getServletContext();
//        2.获取数据
        Object msg = context.getAttribute("msg");
        System.out.println(msg);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request,response);
    }
}