Android：java.lang.IllegalStateException：已连接

Android: java.lang.IllegalStateException: Already connected

提问by Saint Robson

I'm testing a sample of code but its always error at connection.setDoInput(true);

我正在测试一个代码示例，但它总是在 connection.setDoInput(true);

HttpsURLConnection connection = null;
DataOutputStream outputStream = null;
DataInputStream inputStream = null;

String urlServer = "https://www.myurl.com/upload.php";
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";

int bytesRead = 0;
int bytesAvailable = 0;
int bufferSize = 0;
byte[] buffer = null;
int maxBufferSize = 1*1024*1024;

try {
    FileInputStream fileInputStream = new FileInputStream(new File(params[0]));

    URL url = new URL(urlServer);

    connection = (HttpsURLConnection) url.openConnection();
    connection.setConnectTimeout(1000);

    // Allow Inputs & Outputs
    connection.setDoInput(true);
    connection.setDoOutput(true);
    connection.setUseCaches(false);

    // Enable POST method
    connection.setRequestMethod("POST");
    connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);

    connection.setConnectTimeout(1000);

    outputStream = new DataOutputStream(connection.getOutputStream());
    outputStream.writeBytes(twoHyphens + boundary + lineEnd);
    outputStream.writeBytes("Content-Disposition: form-data; name=\"file\";filename=\"" + params[0] + "\"" + lineEnd);
    outputStream.writeBytes(lineEnd);

    bytesAvailable = fileInputStream.available();
    bufferSize = Math.min(bytesAvailable, maxBufferSize);
    buffer = new byte[bufferSize];

    // Read file
    bytesRead = fileInputStream.read(buffer, 0, bufferSize);

    while (bytesRead > 0) {
        outputStream.write(buffer, 0, bufferSize);
        bytesAvailable = fileInputStream.available();
        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        bytesRead = fileInputStream.read(buffer, 0, bufferSize);
    }

    outputStream.writeBytes(lineEnd);
    outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

The error log is java.lang.IllegalStateException: Already connected. I have tried these but none is working:

错误日志是java.lang.IllegalStateException: Already connected. 我试过这些，但没有一个工作：

connection.setRequestProperty("Connection", "close");
connection.disconnect();
connection.setConnectTimeout(1000);

EDIT: even when i didn't call connection.connect(), it's still giving the same error already connected.

编辑：即使我没有打电话connection.connect()，它仍然给出同样的错误already connected。

回答by user3211369

Move

移动

connection.connect();

after

后

connection.setRequestMethod("POST");

回答by Will Calderwood

There is a very good post about http connections here

有一个很好的一篇关于http连接在这里

The bottom line is that for POSTs you only need the following.

最重要的是，对于 POST，您只需要以下内容。

HttpURLConnection connection = (HttpURLConnection) new URL(urlToRead).openConnection();
// setDoOutput(true) implicitly set's the request type to POST
connection.setDoOutput(true);

I'm not sure you need to specify HttpsURLConnection either. You can use HttpURLConnection for connecting to Https sites. Let java do the work for you behind the scenes.

我不确定您也需要指定 HttpsURLConnection 。您可以使用 HttpURLConnection 连接到 Https 站点。让 java 在幕后为您完成工作。

Here is the POST code that I use for json posts

这是我用于 json 帖子的 POST 代码

public static String doPostSync(final String urlToRead, final String content) throws IOException {
    final String charset = "UTF-8";
    // Create the connection
    HttpURLConnection connection = (HttpURLConnection) new URL(urlToRead).openConnection();
    // setDoOutput(true) implicitly set's the request type to POST
    connection.setDoOutput(true);
    connection.setRequestProperty("Accept-Charset", charset);
    connection.setRequestProperty("Content-type", "application/json");

    // Write to the connection
    OutputStream output = connection.getOutputStream();
    output.write(content.getBytes(charset));
    output.close();

    // Check the error stream first, if this is null then there have been no issues with the request
    InputStream inputStream = connection.getErrorStream();
    if (inputStream == null)
        inputStream = connection.getInputStream();

    // Read everything from our stream
    BufferedReader responseReader = new BufferedReader(new InputStreamReader(inputStream, charset));

    String inputLine;
    StringBuffer response = new StringBuffer();

    while ((inputLine = responseReader.readLine()) != null) {
        response.append(inputLine);
    }
    responseReader.close();

    return response.toString();
}

回答by user207421

1. You must close the input stream after reading it to end of stream.

2. You should removethe call to connect(). You have it in the wrong place, but it's automatic and doesn't need to be called at all.

3. You can also remove the line that sets POST. This is implicit in calling setDoOutput(true).

4. You can also remove most of that crud in the copy loop. Use a fixed size buffer:

   while ((count = in.read(buffer)) > 0)
   {
       out.write(buffer, 0, count);
   }
   

   Do not use a new buffer per read; do not call available(); do not pass GO; do not collect $200.

1. 您必须在将输入流读取到流末尾后关闭它。

2. 您应该删除对 的调用connect()。你把它放在错误的地方，但它是自动的，根本不需要调用。

3. 您还可以删除设置 POST 的行。这在调用setDoOutput(true).

4. 您还可以在复制循环中删除大部分 crud。使用固定大小的缓冲区：

   while ((count = in.read(buffer)) > 0)
   {
       out.write(buffer, 0, count);
   }
   

   每次读取不要使用新缓冲区；不要打电话available()；不要通过GO；不要收取 200 美元。

回答by Jeffrey Chen

Add

添加

if (connection != null) connection.disconnect();

before

前

connection = (HttpsURLConnection) url.openConnection();

See if problem solved. If yes, it means connection.disconnect()is not called in your original code. Maybe you put connection.disconnect()at the end of your tryblock, however an exception occurs before it, so it jumps to the catch block and connection.disconnect()is never called.

看看问题是否解决。如果是，则表示connection.disconnect()未在您的原始代码中调用。也许你放在块connection.disconnect()的末尾try，但是在它之前发生了异常，所以它跳转到 catch 块并且connection.disconnect()永远不会被调用。