JSP九大隱式對象分別爲:Request,Response,Session,Application,Config,Page,Exception,Out,pageContext;其用法基本與servlet相同
Application就是servlet中的servletContext對象,即域對象。一個servlet文件有且僅有一個context對象,同樣的,一個JSP文件也有且僅有一個Application對象。
下載圖片:
<%@page import="java.net.URLEncoder"%><%@ pagelanguage="java" import="java.util.*"pageEncoding="UTF-8"%><%@page import="java.io.*"%><%
//得到圖片放置路徑
String path = application.getRealPath("./images/a.jpg");
//將得到的路徑存入到file文件中
File file = new File(path);
//將文件寫入到輸入流中
InputStream is = new FileInputStream(file);
//設置響應頭信息
response.setHeader("content-disposition","attachment;fileName="+URLEncoder.encode(file.getName(),"UTF-8"));
//設置緩衝流
byte buf[] = new byte[1024];
//設置輸出流
OutputStream os = response.getOutputStream();
//判斷
while(is.read(buf)!=-1){
//將輸入流的信息寫入到輸出流中
os.write(buf);
}
os.flush();
os.close();
is.close();
%>
統計訪問首頁的次數:
<%@ pagelanguage="java" import="java.util.*"pageEncoding="UTF-8"%>
<%Object count = application.getAttribute("count");%>
<%if(count==null)
{count=1;
application.setAttribute("count",count);%>
<%}else{
application.setAttribute
("count",(Integer)count+1);}
%>
訪問的次數:<%=count%>