ServletContext共享资源

servlet原理图

ServletContext

web容器在启动的时候，它会为每个web程序都创建了一个对应的ServletContext对象，它代表了当前的web应用

• 共享数据

  我们在这个Servlet中保存的数据，可以在另外一个Servlet中拿到

  public class HelloServlet extends HttpServlet {
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          ServletContext servletContext = this.getServletContext();
          String name = "王铁丸";
          servletContext.setAttribute("name",name);
      }
  }
  

  public class Getc extends HttpServlet {
      @Override
      protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
          ServletContext servletContext = this.getServletContext();
          String name = (String) servletContext.getAttribute("name");
          resp.setCharacterEncoding("utf-8");
          resp.setContentType("text/html");
          PrintWriter writer = resp.getWriter();
          writer.println(name);
  
      }
  }
  

  • web.xml的配置

  <!--注册Servlet-->
    <servlet>
      <servlet-name>hello</servlet-name>
      <servlet-class>com.kuang.servlet.HelloServlet</servlet-class>
    </servlet>
    <!--Servlet的请求路径-->
    <servlet-mapping>
      <servlet-name>hello</servlet-name>
      <url-pattern>/hello</url-pattern>
    </servlet-mapping>
  
    <!--注册Servlet-->
    <servlet>
      <servlet-name>getc</servlet-name>
      <servlet-class>com.kuang.servlet.Getc</servlet-class>
    </servlet>
    <!--Servlet的请求路径-->
    <servlet-mapping>
      <servlet-name>getc</servlet-name>
      <url-pattern>/getc</url-pattern>
    </servlet-mapping>
  

  测试访问结果