为什么服务器上的 Multiform-Upload-Request 为空？

Question

我正在尝试通过 URLConnection 和 multipart/form-data 上传文件并发布一些变量。但是服务器上的请求是空的。

我已经编写了一个非常基本的 PHP 脚本来对解决方案进行原型设计。目前代码如下所示：

$uploaddir = './uploads/';
$uploadfile = $uploaddir . basename($_FILES['file1']['name']);

if(move_uploaded_file($_FILES['file1']['tmp_name'], $uploadfile)) {
  echo 'success ' . $_POST['input1'] . ' ' . $_POST['input2'];
} else {
  echo 'error ';
  var_dump($_FILES);
  echo ' ';
  var_dump($_POST);
}

而我的 Java 测试代码如下：

    URL url = new URL(DEST_URL);
    String boundary = "---------------------" + Long.toString(System.currentTimeMillis());
    PrintWriter writer = null;
    URLConnection con = url.openConnection();

    con.setDoInput(true);
    con.setDoOutput(true);
    con.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
    OutputStream output = con.getOutputStream();
    InputStream input = new FileInputStream(new File(FILE_PATH));
    writer = new PrintWriter(new OutputStreamWriter(output));

    writer.println(boundary);
    writer.println("Content-Disposition: form-data; name=\"input1\"");
    writer.println();
    writer.println("1234");

    writer.flush();

    writer.println(boundary);
    writer.println("Content-Disposition: form-data; name=\"input1\"");
    writer.println();
    writer.println("asdf");

    writer.flush();

    writer.println(boundary);
    writer.println("Content-Disposition: form-data; name=\"file1\"; filename=\"clicknpoint.png\"");
    writer.println("Content-Type: image/png");

    writer.flush();

    int length = 0;
    byte[] buffer = new byte[1024];

    for(length = 0; (length = input.read(buffer)) > 0;) {
        output.write(buffer, 0, length);
    }
    input.close();

    writer.println();
    writer.println(boundary);

    writer.flush();

    input = con.getInputStream();
    BufferedReader reader = new BufferedReader(new InputStreamReader(input));

    String cur = null;
    StringBuffer buf = new StringBuffer();

    while((cur = reader.readLine()) != null) {
        buf.append(cur);
    }

    System.out.println(buf.toString());

    Assert.assertTrue(buf.toString().startsWith("success"));

测试用例失败并打印

    error array(0) {} array(0) {}

我已经使用 wireshark 检查了请求。这就是发送的内容：

POST /test/upload.php HTTP/1.1
Content-Type: multipart/form-data; boundary=---------------------1350394409130
User-Agent: Java/1.6.0_33
Host: localhost
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-Length: 94528

---------------------1350394409130
Content-Disposition: form-data; name="input1"

1234
---------------------1350394409130
Content-Disposition: form-data; name="input1"

asdf
---------------------1350394409130
Content-Disposition: form-data; name="file1"; filename="clicknpoint.png"
Content-Type: image/png
.PNG
.
...
IHDR..............d<.....sRGB.........gAMA......a.....pHYs..........o.d....IDATx^..}.FWy......c,UU.....|.($. .B1..4%..(MC. ...(..j..."<.I.dD.&.DD.&q..Y....P..\..v.!..k...1v....m. // and so on

知道有什么问题吗？

Answer 1

问题是边界无效。边界必须以额外的“--”开头，请求必须以“--”+边界+“--”结束。

这里没有。