JSP的内置对象application让多个JSP和Servlet共享数据实战

浅浅的花香味﹌ 2021-07-24 15:05 247阅读 0赞

**一 put-application.jsp**

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title>application测试</title>
        <meta name="website" content="http://www.crazyit.org" />
    </head>
    <body>
    
    <%!
    int i;
    %>
    
    <%
    application.setAttribute("counter",String.valueOf(++i));
    %>
    
    <%=i%>
    </body>
    </html>

**二 get-application.jsp**

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head>
        <title>application测试</title>
        <meta name="website" content="http://www.crazyit.org" />
    </head>
    <body>
    
    <%=application.getAttribute("counter")%>
    </body>
    </html>

**三 Servlet代码**

package lee;
    
    import javax.servlet.*;
    import javax.servlet.http.*;
    import javax.servlet.annotation.*;
    
    import java.io.*;
    
    
    @WebServlet(name="get-application",
        urlPatterns={"/get-application"})
    public class GetApplication extends HttpServlet
    {
        public void service(HttpServletRequest request,
            HttpServletResponse response)throws IOException
        {
            response.setContentType("text/html;charset=gb2312");
            PrintWriter out = response.getWriter();
            out.println("<html><head><title>");
            out.println("测试application");
            out.println("</title></head><body>");
            ServletContext sc = getServletConfig().getServletContext();
            out.print("application中当前的counter值为:");
            out.println(sc.getAttribute("counter"));
            out.println("</body></html>");
        }
    }

**四 测试**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70]: /images/20210724/48b919cbff9b4f67a310ba553b403485.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1]: /images/20210724/34a194f189c84365b2b9329a76bfbe58.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2]: /images/20210724/2cdb2933b6d047c9ac851df51c047edb.png