Java 将单个字节写入 DataOutputStream

Question

我正在为 HTTP post 请求将单个字节写入 java 中的 DataOutputStream。帖子的结构如下:

/* Init Post */
URL PostToLink = new URL(GeneralArguments.get("PostLink_String"));
byte[] PostData = PutKeyedPostArgs.get("PostBody").getBytes("UTF-8");
HttpURLConnection Post_Request_Connection = (HttpURLConnection) PostToLink.openConnection();
Post_Request_Connection.setDoOutput(true);
Post_Request_Connection.setDoInput(false);
Post_Request_Connection.setRequestMethod("POST");
//Post_Request_Connection.setRequestProperty("charset", "utf-8");
Post_Request_Connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
Post_Request_Connection.setRequestProperty("Content-Length", Integer.toString(PostData.length));
Post_Request_Connection.setRequestProperty("Connection", "Keep-Alive");
Post_Request_Connection.setRequestProperty("User-Agent", UserAgent); // Defined earlier
Post_Request_Connection.setRequestProperty("Cookie", CookieVal); // Defined earlier
Post_Request_Connection.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
Post_Request_Connection.setRequestProperty("Accept-Encoding", "gzip,deflate,sdch");
Post_Request_Connection.setRequestProperty("Accept-Language", "en-US,en;q=0.8");
Post_Request_Connection.setInstanceFollowRedirects(false);
Post_Request_Connection.setUseCaches(false);

/* Obtain Write Stream */
DataOutputStream The_Post_Request_Write_Stream = new DataOutputStream(Post_Request_Connection.getOutputStream());
JOptionPane.showMessageDialog(null, PostData.length); // For Debugging

JOptionPane.showMessageDialog(null, "before for"); // For Debugging
/* Begin writing byte-by-byte to output stream */
for(int CurrentPostByte = 0; CurrentPostByte < PostData.length; CurrentPostByte++){
    JOptionPane.showMessageDialog(null, CurrentPostByte); // For Debugging
    byte[] TemporaryByteArray = new byte[]{PostData[CurrentPostByte]};
    The_Post_Request_Write_Stream.write(TemporaryByteArray, CurrentPostByte, TemporaryByteArray.length);
/* Length should always be 1 */
}

出于某种原因，它在写入第二个字节(位于 PostData[1] 的字节)后出现索引越界错误。我似乎无法找出原因。

如有任何澄清或帮助，我们将不胜感激。谢谢。

Answer 1

看看你的代码:

byte[] TemporaryByteArray = new byte[]{PostData[CurrentPostByte]};
The_Post_Request_Write_Stream.write(TemporaryByteArray, CurrentPostByte, TemporaryByteArray.length);

您正在将长度为 1(一)的数组 TemporaryByteArray 传递给 write 方法，但使用对 PostData 有效的索引> 仅数组。

您可以通过将其更改为以下方式来修复代码:

byte[] TemporaryByteArray = new byte[]{PostData[CurrentPostByte]};
The_Post_Request_Write_Stream.write(TemporaryByteArray, 0, TemporaryByteArray.length);

或者，更简单

byte[] TemporaryByteArray = new byte[]{PostData[CurrentPostByte]};
The_Post_Request_Write_Stream.write(TemporaryByteArray, 0, 1);

或者，更简单

The_Post_Request_Write_Stream.write(PostData, CurrentPostByte, 1);

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但是，当然，最好的解决方案是删除无意义的循环并立即写入整个数组，The_Post_Request_Write_Stream.write(PostData); 而不是逐字节写入。