Http协议
在协议头里面:
Referer:可用来获取请求者 和 可用来做防止盗莲
String referer=req.getHeader("referer");
if (referer==null||!referer.startsWith("http://localhost:8080/JavaMain/")){
out.println("不能盗链");
}else{
out.println("欢迎请求!");
}
Refresh:可用来设置多久后进行页面跳转
1: resp.setHeader("Refresh","5;http://www.google.com.hk");
Web站点下载
1: //进行设置下载文件
2: resp.setHeader("Content-Disposition","attachment;filename=Chrysanthemum.jpg");
3: //打开文件 得某个资源的全路径
4: String path=this.getServletContext().getRealPath("/images/Chrysanthemum.jpg");
5: FileInputStream fileInputStream=
6: new FileInputStream(path);
7: //制作一个缓冲字节数组
8: byte[] buff=new byte[1024];
9: //将数据读入到字节数组内
10: int len; //len表示实际每个读取了多少个字节
11: OutputStream outputStream=resp.getOutputStream();
12: while((len=fileInputStream.read(buff))>0){
13: //将BUFF里面数据进行输出到浏览器
14: //0代表从什么时候开始 len代表实际读取的大小长度
15: outputStream.write(buff,0,len);
16: }
17: outputStream.close();
18: fileInputStream.close();
浏览器缓存:
http输出头:Expires,Cache-Control,Pargma
PrintWriter out=resp.getWriter();//设置页面缓存多长时
resp.setDateHeader("Expires",-1);
resp.setHeader("Cache-Control","no-cache");resp.setHeader("Pragma","no-cache");out.println("Hello,world!"+new Date().toString());