[英]Sending messages to java server in objective-c via AsyncSocket
嗨,我正在嘗試向無法從iOS設備更改的Java服務器發送消息。 我正在使用AsyncSocket,想知道如何發送和接收附加到字符串的長度。 我正在將字符串轉換為NSData的UTF,但是我想知道兩種語言之間的原語大小是否有所不同。 還有大的字節序和小字節序變化嗎? 基本上,我需要能夠轉換以下java方法:
inStream.readUTF();
inStream.readInt();
inStream.readChar();
inStream.readShort();
inStream.readFully(recvBuff, 0, recvLen);
outStream.writeInt();
outStream.writeUTF();
outStream.writeChars();
outStream.writeShort();
outStream.write(sendBytes, 0, sendBytes.length);
我知道我很親近,但有一點不對勁,這就是我到目前為止所取得的成就:
我正在使用NSMutableArray追加數據,並使用AsyncSockets讀取和寫入方法。
[theSocket readDataToData:[AsyncSocket ZeroData] withTimeout:timeout buffer:buffer bufferOffset:offset tag:tag]; // inStream.readUTF();
[theSocket readDataToLength:sizeof(int32_t) withTimeout:timeout buffer:buffer bufferOffset:offset tag:tag]; // inStream.readInt();
[theSocket readDataToLength:sizeof(unichar) withTimeout:timeout buffer:buffer bufferOffset:offset tag:tag]; // inStream.readChar();
[theSocket readDataToLength:sizeof(int16_t) withTimeout:timeout tag:tag]; // inStream.readShort();
[theSocket readDataWithTimeout:timeout buffer:buffer bufferOffset:offset maxLength:maxLength tag:tag]; // inStream.readFully(recvBuff, 0, recvLen);
[outputBufferStream appendBytes:&[sendString length] length:sizeof([sendString length])]; // outStream.writeInt();
[outputBufferStream appendData:[sendString dataUsingEncoding:NSUTF8StringEncoding]] // outStream.writeUTF();
char array[5];
[outputBufferStream appendBytes:array length:sizeof(array)]; // outStream.writeChars();
int16_t _short;
[outputBufferStream appendBytes:&_short length:sizeof(_short)]; // outStream.writeShort();
unsigned char *sendBytes;
[outputBufferStream appendBytes:sendBytes length:sendBytesLength]; // outStream.write(sendBytes, 0, sendBytes.length);
我通常在開頭添加長度,如下所示:
int32_t sendStringLength = [sendString length];
[outputBufferStream appendBytes:&sendStringLength length:sizeof(sendStringLength)];
在本文的結尾,我將以下內容附加為終止符:
[outputBufferStream appendData:[@"\n" dataUsingEncoding:NSUTF8StringEncoding]];
我真的很感謝任何幫助。 謝謝。
編輯::
感謝Robadob,我已經完成了大部分工作。 這是我目前在嘗試使用Objective-C時遇到的一些Java代碼片段(正在工作):
private int sendData(String stringToSend) {
if (theSocket==null) {
lastError="sendData() called before socket was set up.";
return 1; // Error
}
try {
System.out.println("Sending "+stringToSend.length()+" chars ["+ stringToSend.length()*2+" bytes]");
System.out.println("'" + stringToSend + "'");
outStream.writeInt(stringToSend.length()*2);
outStream.writeChars(stringToSend);
outStream.flush();
} catch (IOException e) {
lastError="sendData() exception: "+e;
System.out.println(lastError);
return 2; // Error
}
return 0; // Ok
}
這是我到目前為止在Objective-C中獲得的摘要:
- (int32_t)sendData:(NSString *)stringToSend {
if (theSocket == nil) {
lastError = @"sendData called before socket was set up";
return 1; // Error
}
@try {
NSLog(@"Sending %d chars [%d bytes]", [stringToSend length], ([stringToSend length] * 2));
NSLog(@"'%@'", stringToSend);
uint32_t stringToSendInt = ([stringToSend length] * 2);
uint32_t stringToSendIntBigE = CFSwapInt32HostToBig(stringToSendInt);
[outputBufferStream appendBytes:&stringToSendIntBigE length:sizeof(stringToSendIntBigE)];
stringToSend = [stringToSend stringByAppendingString:@"\n"];
for (int i = 0; i < ([stringToSend length]); i++) {
unichar characterTmp = [stringToSend characterAtIndex:i];
unichar character = characterTmp << 8;
[outputBufferStream appendBytes:&character length:sizeof(character)];
}
[self syncWriteData:outputBufferStream withTimeout:socketTimeout tag:kSendDataSocketTag];
outputBufferStream = [NSMutableData data];
}
@catch (NSException *e) {
lastError = [NSString stringWithFormat:@"sendData exception: %@", [e reason]];
NSLog(@"%@", lastError);
return 2; // Error
}
return 0; // Ok
}
如果您閱讀了writeUTF的文檔,它會說它使用writeShort寫入前2個字節。 這說
將short作為兩個字節寫入基礎輸出流,高字節在前。 如果未引發異常,則寫入的計數器將增加2。
一個字節是8位,因此您正在使用的值int32_t
是32位,因此它們正在寫入的值是16位。 您應該編寫一個int16
或int16_t
(我不是Objective-C)。
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