在Java中从套接字读取未格式化的数据

Question

I have a server socket application which listens on particular ip and port. Then I have client socket which reads input from server and give response. But my problem is that server do not give formatted line termination characters at the end. so when i use buffered reader readline method it hangs. so how should i read the data send by server. here server is basically a API(METER).

Here is sample request/response sequence between server and client.

Request: 8/2/2012 3:28:24 PM.60764 (+0.0000 seconds)
 53 0D                                             S.              
Answer: 8/2/2012 3:28:24 PM.87364 (+0.2656 seconds)
 53 50 31 39 35 30 34 37 38 34 0D                  SP19504784.     
Request: 8/2/2012 3:28:24 PM.92064 (+0.0000 seconds)
 53 48 0D                                          SH.             
Answer: 8/2/2012 3:28:24 PM.02964 (+0.1094 seconds)
 53 48 0D                                          SH.             
Request: 8/2/2012 3:28:24 PM.02964 (+0.0000 seconds)
 53 0D                                             S.              
Answer: 8/2/2012 3:28:24 PM.13964 (+0.1094 seconds)
 53 50 31 39 35 30 34 37 38 34 0D                  SP19504784.     
Request: 8/2/2012 3:28:24 PM.20164 (+0.0000 seconds)
 53 48 0D                                          SH.             
Answer: 8/2/2012 3:28:24 PM.31164 (+0.1094 seconds)
 53 48 0D                                          SH.             
Request: 8/2/2012 3:28:24 PM.31164 (+0.0000 seconds)
 80                                                ?               
Answer: 8/2/2012 3:28:24 PM.46764 (+0.1563 seconds)
 FC                                                ü               
Request: 8/2/2012 3:28:24 PM.46764 (+0.0000 seconds)
 F1                                                ñ               
Answer: 8/2/2012 3:28:25 PM.84264 (+0.3750 seconds)
 8A 31 39 35 30 34 37 38 34 88                     ?19504784?      
Request: 8/2/2012 3:28:25 PM.90464 (+0.0000 seconds)
 F1                                                ñ               
Answer: 8/2/2012 3:28:25 PM.02964 (+0.1250 seconds)
 8A 01 41 32 4D 47 30 31 42 B1                     ?.A2MG01B±      
Request: 8/2/2012 3:28:26 PM.81164 (+0.0000 seconds)
 CA F0 00 00 00 00 00 00 00 3A                     Êð.......:      
Answer: 8/2/2012 3:28:26 PM.02964 (+0.2188 seconds)
 C4 00 05 00 C9 31 36 38 C4 B7 B7 3F 2E C9 74 5A   Ä...É168Ä··?.ÉtZ
 02 00 02 00 FE FC C9 A1 0D 07 00 FB FF FD FC C9   ....þüÉ¡...ûÿýüÉ
 1E 0E FD FF FE FF FD FC C9 B8 FE 4E FF FA 01 FF   ..ýÿþÿýüɸþNÿú.ÿ
 FF B9 D0 F9 F0 3F D0 BF 50 9F                     ÿ¹Ðùð?пP?      

Answer 1

You cannot use readline() if the server doesn't send line endings. However, something in the raw protocol has to indicate when a response is complete. This can be one or more of

1. a specific character sequence
2. the response to each command ("Request" in your sample) has a known, fixed length
3. each response contains the length embedded in it at a fixed offset from the start

You will have to do your own buffering and detect the end of each message yourself. Without a detailed description of the protocol being used, that's about as specific an answer as you can expect.

Answer 2

You could try with one of the read method of BufferedReader, and process any breaks in the data yourself. That's probably the best control you'll have.