url文件的复制
package udp;import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.FileOutputStream;import java.io.InputStream;import java.net.URL;public class url{public static void main(String[] args) throws Exception{URL url1=new URL("file:/D:/1.txt");InputStream is=url1.openStream();DataInputStream dis=new DataInputStream(is);DataOutputStream dos=new DataOutputStream(new FileOutputStream("E:/1.txt"));int length=dis.read();while(length!=-1){dos.write(length);length=dis.read();}dos.flush();if(dos!=null){dos.close();}if(dis!=null){dis.close();}}}?