Http请求和响应应用

//以下载方式打开资源
    public void test4(HttpServletResponse response) throws IOException {
        response.setHeader("content-disposition", "attachment;filename=1.bmp");
        InputStream in = this.getServletContext().getResourceAsStream("/1.bmp");
        int len = 0;
        byte buffer[] = new byte[1024];
        OutputStream out = response.getOutputStream();
        while((len=in.read(buffer))>0){
            out.write(buffer, 0, len);
        }
    }
    //设置响应头，每隔3秒刷新一次
    public void test3(HttpServletResponse response) throws IOException {
        response.setHeader("refresh", "3");//可以用在股票里
        //response.setHeader("refresh", "3:url='http://www.sina.com'");3秒之后刷新到新浪上面去
        //在论坛上，会说3秒后去哪，就是用到这个技术。
        String data = "aaaaaaaaaaaaa";//服务器从浏览器得到的数据
        response.getOutputStream().write(data.getBytes());
    }
    //通过content-type字段控制浏览器以哪种方式打开数据
    public void test2(HttpServletResponse response) throws IOException {
        response.setHeader("content-type", "image/bmp");
        InputStream in = this.getServletContext().getResourceAsStream("/1.bmp");
        int len = 0;
        byte buffer[] = new byte[1024];
        OutputStream out = response.getOutputStream();
        while((len=in.read(buffer))>0){
            out.write(buffer, 0, len);
        }
    }
    
    //压缩数据输出
    public void test1(HttpServletResponse response) throws IOException {
        String data="aaaaaaaaa";
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        GZIPOutputStream gout = new GZIPOutputStream(bout);
        //ByteArrayOutputStream叫底层流，GZIPOutputStream包装流，包装流会有一个缓冲的，调用包装流写数据的时候，
        //如果数据量没有把包装流的缓冲写满，他是不会往底层流里面写的，为了确保一定能够取到数据，添加gout.close();
        gout.write(data.getBytes());
        gout.close();
        byte gzip[] = bout.toByteArray();//得到压缩后的数据
        //给浏览器之后浏览器不知道是压缩数据，一定要通过设置响应头，通知浏览器数据采用的压缩格式,不然会出现错误
        response.setHeader("Content-Encoding", "gzip");
        response.setHeader("Content-Length", gzip.length+"");
        response.getOutputStream().write(gzip);
    }
//实现断点下载，请求里面包含range头
    public static void test6() throws MalformedURLException, IOException,
            FileNotFoundException {
        //已接受aaaaa  源文件aaaaaaaaaaaaaaaaaaaaa
        URL url = new URL("http://localhost:8080/day05/a.txt");
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestProperty("Range", "bytes=5-");
        
        InputStream in = conn.getInputStream();
        
        int len=0;
        byte buffer[] = new byte[1024];
        FileOutputStream out = new FileOutputStream("c:\a.txt",true);//追加
        while((len=in.read(buffer))>0){
            out.write(buffer, 0, len);
        }
        in.close();
        out.close();
    }