在Java语言中,与Internet地址有关的类是()
A. Socket
B. UDPSocket
C. DatagramSocket
D. InetAddress
查看答案
关于Socket通信编程,以下选项错误的是()
A. 服务器端通过new ServerSocket()创建TCP连接对象
B. 服务器端通过TCP连接对象调用accept()方法创建通信的Socket对象
C. 客户端通过new Socket()方法创建通信的Socket对象
D. 客户端通过new ServerSocket()创建TCP连接对象
JDBC中回滚事务是使用Connection接口的()方法
A. commit()
B. rollback()
C. close()
D. setAutoCommit()
以下代码实现了文件的拷贝。请给出缺失的代码,使程序能正确执行。public static void copyFile(String srcfilePathAndName, String targetfilePathAndName) {try {File sourceFile = new ____(1)_____;FileInputStream in = new FileInputStream(srcfilePathAndName);int len = (int)sourceFile.length();byte[] bt = new ____(2)___;in.read(bt); //读取bt.length个字节数据存放到bt字节数组中File copyFile = new File(targetfilePathAndName);FileOutputStream out = new FileOutputStream(copyFile);____(3)____; //将bt字节数组数据写入文件中out.close();in.close();} catch (IOException e) {e.printStackTrace();}}
以下代码实现了客户端与服务端的数据传输。请给出缺失的代码,使程序能正确执行。public class Ex8_2S {public static void main(String[] args) throws Exception{byte buf[]=new byte[1024];DatagramPacket dp=new DatagramPacket(buf,buf.length);DatagramSocket ds=new ____(1)____;System.out.println("Server started.");while(true){____(2)____; //阻塞式的接收System.out.println(new String(buf,0,dp.getLength())+",Server!");}}}public class Ex8_2C {public static void main(String[] args) throws Exception{byte[] buf=(new String("Hello")).getBytes();InetSocketAddress isa = new InetSocketAddress("127.0.0.1",5678);DatagramPacket dp= new DatagramPacket(____(3)____);DatagramSocket ds=new DatagramSocket(9999);____(4)____; //发送到指定的服务器端口ds.close();}}