1 import java.io.BufferedReader; 2 import java.io.BufferedWriter; 3 import java.io.File; 4 import java.io.FileInputStream; 5 import java.io.FileNotFoundException; 6 import java.io.FileOutputStream; 7 import java.io.IOException; 8 import java.io.InputStreamReader; 9 import java.io.OutputStreamWriter;10 11 public class CopyFileDemo {12     public static void main(String[] args) {13         File file = new File("D://code");14         String suffix = ".java";15         findFile(file, suffix);16         System.out.println("文件复制成功!");17     }18     /**19      * 遍历目录，找出后缀为.java的文件20      * 21      * @param file22      * @param suffix23      */24     public static void findFile(File file, String suffix) {25         if (file == null)26             return;27         if (file.isDirectory()) {// 如果file对象是目录28             File[] files = file.listFiles();29             if (files != null) {30                 for (File f : files) {31                     findFile(f, suffix);32                 }33             }34         } else {// 如果file对象是文件35             //获取jpg路径名36             String path = file.getPath().toLowerCase();37             //截取jpg文件名前缀38             String prefixName = path.substring(path.lastIndexOf("\\")+1, path.indexOf("."));39             String newFileName = prefixName + ".txt";40             if (path.endsWith(suffix)) {41                 // 如果文件是java文件，复制到另一个目录42                 File targetFile = new File("F:\\test" + File.separator + newFileName);43                 copyFile(file, targetFile);44             }45         }46     }47     /**48      * 复制文件到另一个目录，同时修改文件后缀为.txt49      * 50      * @param sourceFile51      * @param targetFile52      * @param prefix53      * @param suffix54      */55     public static void copyFile(File sourceFile, File targetFile) {56         String line = null;57         BufferedReader br = null;58         BufferedWriter bw = null;59         try {60             br = new BufferedReader(new InputStreamReader(new FileInputStream(61                     sourceFile)));62             bw = new BufferedWriter(new OutputStreamWriter(63                     new FileOutputStream(targetFile)));64             while ((line = br.readLine()) != null) {65                 bw.write(line);66                 bw.flush();67             }68         } catch (FileNotFoundException e) {69             e.printStackTrace();70         } catch (IOException e) {71             e.printStackTrace();72         } finally {73             try {74                 br.close();75                 bw.close();76             } catch (Exception e) {77                 e.printStackTrace();78             }79         }80     }81 }