JAVA程序员培训定制课程.ppt

第十五章,网络编程,2,本章内容,使用包中的类在程序中实现网络通信URL类及其用法Socket通信,3,URL,URL(UniformResourceLocator)-统一资源定位器，表示Internet上某一资源的地址。URL组成:协议名和资源名protocol:resourceNameURL举例:,4,.URL类,常用构造方法publicURL(Stringspec);URLu1=newURL(“URLu2=newURL(u1,“welcome.html”);publicURL(Stringprotocol,Stringhost,Stringfile);URLu3=newURL(“http”,“”,“developers/index.html”);publicURL(Stringprotocol,Stringhost,intport,Stringfile);URLu4=newURL(“http”,“”,80,“developers/index.html”);,5,URL类应用举例(1),importjava.io.*;.*;publicclassURLReaderpublicstaticvoidmain(Stringargs)tryURLtirc=newURL(BufferedReaderin=newBufferedReader(newInputStreamReader(tirc.openStream();Strings;while(s=in.readLine()!=null)System.out.println(s);in.close();catch(MalformedURLExceptione)System.out.println(e);catch(IOExceptione)System.out.println(e);,6,URL类应用举例(2),程序URLReader.java输出结果:清华大学网站首页,7,Socket,两个Java应用程序可通过一个双向的网络通信连接实现数据交换，这个双向链路的一端称为一个socket。socket通常用来实现client-server连接。包中定义的两个类Socket和ServerSocket，分别用来实现双向连接的client和server端建立连接时所需的寻址信息远程计算机的机器名或IP地址试图连接的端口号(Portnumber),8,Socket通信模型,Server,ServerSockets(port#),s.accept()/等待连接,Socket(),OutputStream,InputStream,socket.close(),Client,Socket(host,port#)（Attempttoconnect）,OutputStream,InputStream,socket.close(),9,网络编程的四个基本步骤,创建socket;打开连接到socket的输入/输出流；按照一定的协议对socket进行读/写操作；关闭socket;,10,创建socket,Socket/ServerSocket类的构造方法Socket(InetAddressaddress,intport);Socket(InetAddressaddress,intport,booleanstream);Socket(Stringhost,intport);Socket(Stringhost,intport,booleanstream);ServerSocket(intport);ServerSocket(intport,intcount);,11,客户端Socket的建立trySocketsocket=newSocket(”,2000);catch(IOExceptione)System.out.println(Error:+e);,12,服务器端Socket的建立ServerSocketserver=null;tryserver=newServerSocket(2000);catch(IOExceptione)System.out.println(cannotlistento:+e);Socketsocket=null;trysocket=server.accept();catch(IOExceptione)System.out.println(Error:+e);,13,打开输入/出流PrintStreamos=newPrintStream(newBufferedOutputStream(socket.getOutputStream();DataInputStreamis=newDataInputStream(socket.getInputStream();关闭Socketos.close();is.close();socket.close();,14,简单的client/server程序,.*;importjava.io.*;publicclassTestServerpublicstaticvoidmain(Stringargs)ServerSockets=null;trys=newServerSocket(8888);catch(IOExceptione)while(true)trySockets1=s.accept();OutputStreamos=s1.getOutputStream();DataOutputStreamdos=newDataOutputStream(os);dos.writeUTF(Hello,bye-bye!);dos.close();s1.close();catch(IOExceptione),15,简单的client/server程序,.*;importjava.io.*;publicclassTestClientpublicstaticvoidmain(Stringargs)trySockets1=newSocket(,8888);InputStreamis=s1.getInputStream();DataInputStreamdis=newDataInputStream(is);System.out.println(dis.readUTF();dis.close();s1.close()