Question

android java 函数返回字符串问题

DataTrans trans = new DataTrans(Data.ip, Data.port);
int ret = trans.connect();
if(ret != Error.ERROR_SUCCESS) return ret;

StringBuffer send = new StringBuffer();
send.append("orderlist");
send.append("#");
send.append(String.valueOf(count));
for(int i=0;i<count;i++){
send.append("#");
send.append(data.getSelName(i));
send.append("%");
send.append(data.getSelItemNum(i));
}
ret = trans.send(send.toString());
send = null;
if(ret != Error.ERROR_SUCCESS) return ret;
String recv = trans.recv();
trans.close();

当count较大时，即发送的字符串较长时，recv就是null

DataTrans类申明如下：

public class DataTrans {

private String ip;
private int port;

Socket socket = null;
InputStream in = null;
OutputStream out = null;
BufferedWriter bw = null;

byte[] buff = new byte[1024];

public DataTrans(String ip, int port){
this.ip = ip;
this.port = port;
}

public int connect() {
try {
socket = new Socket();
SocketAddress socketAddress = new InetSocketAddress(ip, port);
socket.connect(socketAddress,5000);
} catch (UnknownHostException e) {
e.printStackTrace();
return Error.ERROR_OPEN_SOCK;
} catch (IOException e) {
e.printStackTrace();
return Error.ERROR_OPEN_SOCK;
}
try {
out = socket.getOutputStream();
in = socket.getInputStream();
bw = new BufferedWriter(new OutputStreamWriter(out));
} catch (IOException e) {
e.printStackTrace();
return Error.ERROR_OPEN_SOCK;
}
return Error.ERROR_SUCCESS;
}

public int send(String msg){
try {
bw.write(msg);
bw.flush();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return Error.ERROR_WRITE_SOCK;
}
return Error.ERROR_SUCCESS;
}

public String recv(){
int read = 0;
StringBuffer strBuff = new StringBuffer();
while (true) {
if (in != null) {
try {
read = in.read(buff, 0, 1024);
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
if (read == -1) {
break;
}
String temp = null;
try {
temp = new String(buff, 0, read, "GBK");
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
strBuff.append(temp);
temp = null;
}
return strBuff.toString();
}
public void close(){.....}
}

不知道为什么，就是count 较大时， 调试时DataTrans的recv()在返回前 strBuff是有数据的，但recv()返回给String recv为null

若以下回答无法解决问题，邀请你更新回答

Answer 1

虽然不太清楚，但是怀疑是不是由于发送过程较慢，所以返回了大量的数据，倒是缓存满了？
建议recv放到另一个线程里面试一下，避免发送方的阻塞