JSP中的9个内置对象

JSP提供了9个内置对象，在JSP页面中可以直接使用这九个对象。

 

内置对象：

 

对象名	类	说明
request	javax.servlet.http.HttpServletRequest	客户端请求
response	javax.servlet.http.HttpServletResponse	客户端响应
page	java.lang.Object	JSP页面
pageContext	javax.servlet.jsp.PageContext	页面上下文，管理页面范围内的对象
session	javax.servlet.http.HttpSession	管理session范围内的对象
application	javax.servlet.ServletContext	管理应用范围内的对象
out	javax.servlet.jsp.JspWriter	向客户端输出信息
config	javax.servlet.ServletConfig	取得在web.xml中定义的初始化参数
exception	java.lang.Throwable	异常

 

下面是对应的java代码：

 

public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response)
        throws java.io.IOException, javax.servlet.ServletException {

    final javax.servlet.jsp.PageContext pageContext;
    javax.servlet.http.HttpSession session = null;
    java.lang.Throwable exception = org.apache.jasper.runtime.JspRuntimeLibrary.getThrowable(request);
    if (exception != null) {
      response.setStatus(javax.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
    }
    final javax.servlet.ServletContext application;
    final javax.servlet.ServletConfig config;
    javax.servlet.jsp.JspWriter out = null;
    final java.lang.Object page = this;
    javax.servlet.jsp.JspWriter _jspx_out = null;
    javax.servlet.jsp.PageContext _jspx_page_context = null;


    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;

 

注意：exception对象只有在JSP页面中指定 <%@ page isErrorPage="true"%> 才会创建。