Jsp中的静态引入和动态引入

原创

lxn1615404043 2022-11-23 06:21:55 博主文章分类：java ©著作权

文章标签 html 3c apache 文章分类 虚拟化云计算

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前言

在jsp中，要引入一个外部文件可以通过两种方式：

I.通过jsp指令<%@include file="" %>引入
II.通过jsp动作标签<jsp:inclue page="">引入

其中第一种方式称为静态引入，第二种方式称为动态引入

静态引入

静态引入是指在把两个页面翻译成Servlet的过程中进行合并
下面是静态引入合并后的Servlet的代码

try {
      response.setContentType("text/html; charset=utf-8");
      pageContext = _jspxFactory.getPageContext(this, request, response,
                null, true, 8192, true);
      _jspx_page_context = pageContext;
      application = pageContext.getServletContext();
      config = pageContext.getServletConfig();
      session = pageContext.getSession();
      out = pageContext.getOut();
      _jspx_out = out;

      out.write("\r\n");
      out.write("    ");
      out.write("\r\n");
      out.write("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">\r\n");
      out.write("<html>\r\n");
      out.write("<head>\r\n");
      out.write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=ISO-8859-1\">\r\n");
      out.write("<title>Insert title here</title>\r\n");
      out.write("</head>\r\n");
      out.write("<body>\r\n");
      out.write('\r');
      out.write('\n');
      out.write("\r\n");
      out.write("\t<!--  -->\r\n");
      out.write("\t<h3>Simple2</h3>\r\n");
      out.write("\t");
out.println(a); 

      out.write("\r\n");
      out.write("</body>\r\n");
      out.write("</html>");
      out.write("\r\n");
      //第二个页面
      out.write("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">\r\n");
      out.write("<html>\r\n");
      out.write("<head>\r\n");
      out.write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=ISO-8859-1\">\r\n");
      out.write("<title>Insert title here</title>\r\n");
      out.write("</head>\r\n");
      out.write("<body>\r\n");
      out.write("\t<!-- 动态引入 -->\r\n");
      out.write("\t");
pageContext.setAttribute("name", "张三"); 
        application.setAttribute("age", 12);

      out.write("\r\n");
      out.write("\t\r\n");
      out.write("\t");

从合并后的Servlet的代码可以看出，静态引入完全是把一个页面的内容合并到了另一个页面(除了page指令)

动态引入

动态引入是指在Servlet的运行过程中，通过代码引入另一个页面

out.write("\r\n");
      out.write("<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">\r\n");
      out.write("<html>\r\n");
      out.write("<head>\r\n");
      out.write("<meta http-equiv=\"Content-Type\" content=\"text/html; charset=ISO-8859-1\">\r\n");
      out.write("<title>Insert title here</title>\r\n");
      out.write("</head>\r\n");
      out.write("<body>\r\n");
      out.write("\t<!-- 动态引入 -->\r\n");
      out.write("\t");
//通过JspRuntimeLibrary的include方法引入jsp页面  org.apache.jasper.runtime.JspRuntimeLibrary.include(request, response, "simple.jsp", out, false);
      out.write('\r');
      out.write('\n');
      out.write('   ');
pageContext.setAttribute("name", "张三"); 
        application.setAttribute("age", 12);

      out.write("\r\n");