在pc上通过socket从android手机上接收屏幕截屏

    使用ByteBuffer包装byte数组，简化加入数据操作。前面4个字节指示待接收图片大小，紧跟着是截屏图片数据。原先的实现比较粗糙，下面是我改写之后的代码，逻辑上还是比较严密的。

InOutStructure inOutStructure = InOutStructure
                .getInOutStructure(serialNumber);

        int length = 0;
        byte[] captureBuffer = cc.getCaptureBuffer();

        ByteBuffer bb = ByteBuffer.wrap(captureBuffer);

        try {
            inOutStructure.GetOut().println(cmd);
            // flush会添加回车换行符
            inOutStructure.GetOut().flush();

            byte[] buffer = new byte[1024];

            // 此处可能抛：java.net.SocketException
            int dataLen = inOutStructure.getIn().readInt();
            int remainder = dataLen;

            while(true) {
                // 准备接收的长度
                int expect_recv_len = (remainder > 1024) ? 1024 : remainder;
                int read = inOutStructure.getIn().read(buffer, 0, expect_recv_len);
                length += read;

                // 此处read可能为-1
                bb.put(buffer, 0, read);

                remainder = dataLen - length;
                // 如果剩余接收长度为0，说明已经接收完全
                if (remainder == 0) {
                    break;
                }
            }

            // 将截屏结果缓存起来
            TaskResult.cacheCaptureBuffer(serialNumber, captureBuffer, length);
        } catch (IOException e) {
            e.printStackTrace();
        }