TCP与UDP客户服务端实现大小写及SOCKET编程实现聊天程序.doc

TCP实现大小写转换代码如下
importjava.io.*;
importjava.net.*;
classTCPServer{
publicstaticvoidmain(Stringargv[])throwsException
{
StringClientSentence;
StringcapitalizedSentence;
@SuppressWarnings("resource")
ServerSocketwelcomeSocket=newServerSocket(8998);
while(true){
SocketconnectionSocket=welcomeSocket.accept();
BufferedReaderinfromClient=
newBufferedReader(newInputStreamReader(
connectionSocket.getInputStream()));
DataOutputStreamoutToClient=
newDataOutputStream(
connectionSocket.getOutputStream());
ClientSentence=infromClient.readLine();
capitalizedSentence=
ClientSentence.toUpperCase()+'\n';
outToClient.writeBytes(capitalizedSentence);
}
}
}

TCP服务器代码：

importjava.io.*;
importjava.net.*;
classTCPClient{
publicstaticvoidmain(Stringargv[])throwsException
{
Stringsentence;
StringmodifiedSentence;
BufferedReaderinfromUser=
newBufferedReader(
newInputStreamReader(System.in));
SocketclientSocket=newSocket("127.0.0.1",8998);
DataOutputStreamoutToServer=
newDataOutputStream(
clientSocket.getOutputStream());
BufferedReaderinfromServer=
newBufferedReader(newInputStreamReader(
clientSocket.getInputStream()));
sentence=infromUser.readLine();
outToServer.writeBytes(sentence+'\n');
modifiedSentence=infromServer.readLine();
System.out.println("FROMSERVER:"+
modifiedSentence);
clientSocket.close();
}
}
运行结果截图:

UDP实现大小写转换
UDPServer短代码：
importjava.net.*;
importjava.io.*;
publicclassServer{
publicstaticvoidmain(Stringargs[])throwsSocketException,IOException{
DatagramSocketsocket;
DatagramPacketpacket;
byte[]buf=newbyte[256];
intport;
InetAddressadd;
socket=newDatagramSocket(8888);
packet=newDatagramPacket(buf,buf.length);
booleanb=true;
while(b){
socket.receive(packet);
Strings=newString(packet.getData()).trim();
System.out.println("服务器接受数据为："+s);
//Stringstr=s-('a'-'A');
Stringstr=s.toUpperCase();
s=String.valueOf(str);
buf=s.getBytes();
packet=newDatagramPacket(buf,buf.length,packet.getAddress()