<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'downloadurlpicture.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css" target="_blank" rel="external nofollow" target="_blank" rel="external nofollow" mce_href="styles.css" target="_blank" rel="external nofollow" target="_blank" rel="external nofollow" >
-->
</head>
<body>
<%
//下载网络文件
int bytesum = 0 ;
int byteread = 0 ;
//链接网络文件
String urlStr = request.getParameter("url");
URL url = new URL(urlStr);
OutputStream os = null;
String fileName = urlStr.substring(urlStr.lastIndexOf("/")+1,urlStr.length());
try
{
URLConnection conn = url.openConnection();
InputStream inStream = conn.getInputStream();
response.reset();
//如果要报这个异常(java.lang.IllegalStateException: getOutputStream() has already been called for this response)，请把下面注释的代码启用
//out.clear();
//out=pageContext.pushBody();
//设置输出的格式，以附件的方式输出，不用用浏览器打开
response.addHeader("Content-Disposition", "attachment;filename=" + new String(fileName));
os = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
byte[] buffer = new byte[1204];
while((byteread = inStream.read(buffer)) != -1 )
{
bytesum += byteread;
os.write(buffer,0,byteread);
}
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
os.flush();
os.close();
}
%>
</body>
</html>
![Java小案例——随机数猜测随机数猜测[图]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)