09 2013 档案

摘要：基本没有问题，传输效率很高，缺点如博主所说，cpu占用问题，估计是浪费在指令、校验和判断上了，如果接收到我的文件用异步写入，应该也会减少点cpu时间。另外，博主可以尝试一下用md5校验，虽然有16字节，但是比crc32的效率快很多，cpu占用也少，在我的机器上实测，crc32，校验一个byte[]，4兆字节用时7毫秒，400兆字节用时190多毫秒，而md5校验同样的字节数，分别用0毫秒和60多毫秒。0毫秒就是还没到1毫秒就完成了呵呵。我计时的方法是在computeHash之前timer.start(),之后stop，应该算精确的。期待与各位精通socket的朋友交流，goodies.qq@gm 阅读全文

摘要：ASCII方式：一个英文字母占一个字节，不能保存汉字；UTF8方式：一个英文字母占一个字节，一个汉字占三个字节；unicode方式：一个英文字母和一个汉字都占两个字节。基于TCP的Socket服务端：1、客户端以UTF8编码发送数据，假如发送的数据是汉字的情况下 服务端进行接收的时候，接收的缓冲区的长度必须至少大于等于3个字节。 byte[] buffer = new byte[length] // length的长度>=32、客户端以unicode编码发送数据，假如发送的数据是汉字的情况下 服务端进行接收的时候，接收的缓冲区的长度必须至少大于等于2个字节 byte[] bu... 阅读全文

摘要：ConclusionAnd that's all there is to it! Here is how our client looks likeHere is how our server looks likeThat is all there is to the socket programming. 阅读全文

摘要：Server SideIf you have understood whatever I have described so far, you will easily understand the Server part of the socket application. So far we have been talking about a client making connection to a server and sending and receiving data.On the Server end, the application has to send and receive 阅读全文

摘要：Now lets say you have two sockets connecting to either two different servers or same server (which is perfectly valid) . One way is to create two different delegates and attach a different delegate to different BeginReceive function. What if you have 3 sockets or for that matter n sockets , this app 阅读全文

摘要：Getting StartedYou can argue that one can overcome these shortcomings by multithreading meaning that one can spawn a new thread and let that thread do the polling which then notifies the main thread of the data. This concept could work well, but even if you create a new thread it would require your 阅读全文

摘要：This is the second part of the previous article about the socket programming. In the earlier article we created a client but that client used to make blocking IO calls ( Receive ) to read data at regular intervals (via clicking the Rx button). But as I said in my earlier article, that model does not 阅读全文