File类,IO流练习题目

编写一个程序，将d:\java目录下的所有.java文件复制到d:\jad目录下，并将原来文件的扩展名从.java改为.jad。public class Demo {public static void main(String[] args) throws Exception {// 封装这个目录File srcFile = new File("E:\\java");// 过滤器FilenameFilter ff = new FilenameFilter() {@Overridepublic boolean accept(File dir, String name) {return new File(dir, name).isFile() && name.endsWith("java");}};// 获取该目录下所有满足条件的file[]数组File[] fileArray = srcFile.listFiles(ff);// 判断是否存在目的地目录,如果没有,就创建File destFile = new File("E:\\jad");if (!destFile.exists()) {destFile.mkdir();}// 遍历File数组,获取到每一个Filefor (File file : fileArray) {String name = file.getName();String newName = name.replace(".java", ".jad");File newFile = new File(destFile, newName);// 复制文件BufferedReader br = new BufferedReader(new FileReader(file));BufferedWriter bw = new BufferedWriter(new FileWriter(newFile));String line = null;while ((line = br.readLine()) != null) {bw.write(line);bw.newLine();bw.flush();}bw.close();br.close();}}}