Android 在yeelink下载图片

一开始写了一个用socket下载数据的代码，是成功可以下载到数据了

    public String Request(String url)
    {
        String str;
        PrintWriter out = null;

        if(socket != null)
        {
            try {
                out = new PrintWriter(socket.getOutputStream());
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            out.print("GET /v1.0/");
            out.print(url);
            out.print(" HTTP/1.1\r\n");
            out.print("Host:api.yeelink.net\r\n");
            out.print("Accept: */*\r\n");
            out.print("U-ApiKey:***************\r\n");          //抱歉！key不能公布，用**代替
            out.print("Content-Length:0\r\n");
            out.print("Connection: close\r\n");
            out.print("\r\n");
            out.println("print get done.\r\n");
            out.flush();

            str = Receive();
            if( ( (String)str.subSequence(9, 12) ).equals("200") )
            {
                //数据解析
            }
            else
            {
                try {
                    socket = new Socket("42.96.164.52",80);
                } catch (UnknownHostException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                str = Request(url);
            }
            return str;
        }
        return null;
    }

后来在下载图片的时候，由于不知道怎么截取到图片的数据，所以想改用HttpURLConnection进行下载，这时候就出问题了

    public static byte[] HttpReceive()
    {
        byte[] v = null;
        try {

            URL url = new URL("http://api.yeelink.net/v1.0/device/342273/sensor/379602/photo/content/2015-11-27T08:54:32");
            HttpURLConnection hc = (HttpURLConnection)url.openConnection();

            hc.setRequestMethod("GET");
            hc.setDoInput(true);
            hc.setUseCaches(false);
            hc.setInstanceFollowRedirects(true);
            hc.setRequestProperty("Host", "api.yeelink.net");
            hc.setRequestProperty("Accept", "*/*");
            hc.setRequestProperty("U-ApiKey", "******");            
            hc.setRequestProperty("Content-Length", "0");
            hc.setRequestProperty("Connection", "close");
//          hc.setRequestProperty("Content-type", "image/jpeg"); 

            hc.connect(); 
            InputStream is = hc.getInputStream();
            int streamLength = (int)is.available();
            byte[] b = new byte[streamLength];
            is.read(b, 0, streamLength);
            return b;
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return v;
    }

出现了filenotfoundexception异常

有人知道是什么原因吗

你没有判断返回码，确定拿到数据了吗？都报文件找不到异常了，再检查一下吧。

byte[] v = null;
你的v一直为null啊，你要把b赋值给v

你请求的数据是图片的话，那你的url后面的文件名的后缀应该加上去
"http://api.yeelink.net/v1.0/device/342273/sensor/379602/photo/content/2015-11-27T08:54:32"

换成post试一下， hc.setRequestMethod("post");

莫名其妙又可以了。。。。