ServerletContext

ServerletContext

• ServerletContext是一种各serverlet项目间互相传输数据的存储器

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  • 写入

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class write extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        System.out.println("doget已经运行了");
        //创建ServletContext对象
        ServletContext con= this.getServletContext();

        resp.setCharacterEncoding("utf-8");
        resp.setContentType("text/html");

        con.setAttribute("name","engagering");


    }
}

• 读

  import javax.servlet.ServletContext;
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServlet;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.IOException;
  import java.io.PrintWriter;
  
  public class read extends HttpServlet {
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          System.out.println("doget已经运行了");
          ServletContext con= this.getServletContext();
          resp.setCharacterEncoding("utf-8");
          resp.setContentType("text/html");
            //用String类型的收取,别忘了强制类型转换
         String s= (String)con.getAttribute("name");
  
         resp.getWriter().print(s);
  
  
      }
  }
  

• xml文件

  <?xml version="1.0" encoding="UTF-8"?>
  <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
           version="4.0">
      <servlet>
          <servlet-name>read</servlet-name>
          <servlet-class>com.engagering.serverletcontext1.read</servlet-class>
      </servlet>
      <servlet-mapping>
          <servlet-name>read</servlet-name>
          <url-pattern>/read</url-pattern>
      </servlet-mapping>
      <servlet>
          <servlet-name>write</servlet-name>
          <servlet-class>com.engagering.serverletcontext1.write</servlet-class>
      </servlet>
      <servlet-mapping>
          <servlet-name>write</servlet-name>
          <url-pattern>/write</url-pattern>
      </servlet-mapping>
  </web-app>
  

   <url-pattern>/write</url-pattern>
  </servlet-mapping>
  

  ```