android-Android向PHP服务端上传文件报FileNotFoundExce

服务端：（auth变量为用户登录状态验证，这部分确认没错。）

if( $auth==1){    $target_path = ROOT.basename($_FILES['uploadedfile']['name']);    echo $target_path;    if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {        echo "The file ".  basename( $_FILES['uploaded_file']['name']). " has been uploaded";     } else{        echo "There was an error uploading the file, please try again!" . $_FILES['uploadedfile']['error'];    } }else{    echo 'error_login';}

客户端：

private String uploadFile = Environment.getExternalStorageDirectory()+ "/" + packageName + "/" + "images" + "/" + "image.jpg";private String srcPath = Environment.getExternalStorageDirectory()+ "/" + packageName + "/" + "images" + "/" + "image.jpg";private String actionUrl = getTargetUrl(); //PHP连接 private void uploadFile(final String uploadUrl) {        Thread thread = new Thread() {            @Override            public void run() {                //DEBUG                File file = new File(uploadFile);                if(file.exists()){                    Log.i("DEBUG","要上传的文件存在");                }                String end = "\r\n";                String twoHyphens = "--";                String boundary = "******";                try {                    URL url = new URL(uploadUrl);                    HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();                    // 设置每次传输的流大小，可以有效防止手机因为内存不足崩溃                    // 此方法用于在预先不知道内容长度时启用没有进行内部缓冲的 HTTP 请求正文的流。                    httpURLConnection.setChunkedStreamingMode(128 * 1024);// 128K                    // 允许输入输出流                    httpURLConnection.setDoInput(true);                    httpURLConnection.setDoOutput(true);                    httpURLConnection.setUseCaches(false);                    // 使用POST方法                    httpURLConnection.setRequestMethod("POST");                    httpURLConnection.setRequestProperty("Connection", "Keep-Alive");                    httpURLConnection.setRequestProperty("Charset", "UTF-8");                    httpURLConnection.setRequestProperty("Content-Type",                            "multipart/form-data;boundary=" + boundary);                    DataOutputStream dos = new DataOutputStream(httpURLConnection.getOutputStream());                    dos.writeBytes(twoHyphens + boundary + end);                    dos.writeBytes("Content-Disposition: form-data; name=\"uploadedfile\"; filename=\""                            + srcPath.substring(srcPath.lastIndexOf("/") + 1)                            + "\""                            + end);                    dos.writeBytes(end);                    FileInputStream fis = new FileInputStream(srcPath);                    byte[] buffer = new byte[8192]; // 8k                    int count = 0;                    // 读取文件                    while ((count = fis.read(buffer)) != -1) {                        dos.write(buffer, 0, count);                    }                    fis.close();                    dos.writeBytes(end);                    dos.writeBytes(twoHyphens + boundary + twoHyphens + end);                    dos.flush();                    InputStream is = httpURLConnection.getInputStream();                    InputStreamReader isr = new InputStreamReader(is, "utf-8");                    BufferedReader br = new BufferedReader(isr);                    String result = br.readLine();                    dos.close();                    is.close();                } catch (Exception e) {                    e.printStackTrace();                    setTitle(e.getMessage());                }            }        };        thread.start();    }

运行后返回错误：（包含服务端接收页面的链接）
报错后运行也中止了，没有收到服务端打印的任何信息。
java.io.FileNotFoundException: http://.../upload.php
at com.android.okhttp.internal.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:206)
Studio指示错误的行是：
InputStream is = httpURLConnection.getInputStream();

起初以为是本地文件不存在，结果用文件管理器确认、包括代码中检查后也打出了“文件存在“，可以确定的是客户端文件路径没错。后来以为URL链接有问题，用电脑浏览器可以正常打开，可以打印内容，所以服务端链接也应没错。

百思不得其解，搜索很久也没找到解决方案，特来求助。求老司机带一带。