Get_data.java

package cn.web.servlet_context;

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;

@WebServlet("/get_data")
public class Get_data extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        /*
        ServletContext功能：
           1. 获取MIME类型：

            2. 域对象：共享数据
            3. 获取文件的真实(服务器)路径
         */
        //2. 通过HttpServlet获取
        ServletContext context = this.getServletContext();

        Object msg = context.getAttribute("msg");
        System.out.println(msg);
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}