java調用diff命令

public File runDiff(File oldFile,File newFile,File compareFile,Logger log){//oldFileName=(oldFile.getPath()).replace('\\', '/');oldFileName=oldFile.getPath();System.out.println("filename"+oldFileName);//newFileName=(newFile.getPath()).replace('\\', '/');newFileName=newFile.getPath();String[] commands=new String[3];commands[0]="diff";commands[1]=oldFileName;commands[2]=newFileName;log.info("command"+commands.toString());try{Process proc=Runtime.getRuntime().exec(commands);InputStream in = proc.getInputStream();           InputStreamReader reader = new InputStreamReader(in);          BufferedReader bufferedReader = new BufferedReader(reader);         BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(compareFile));         char buf[] = new char[1024];         //字元緩衝區         int len;         while ((len = bufferedReader.read(buf)) != -1)        {         bufferedWriter.write(buf, 0, len);          }         bufferedWriter.flush();         bufferedReader.close();         bufferedWriter.close(); }catch(IOException e){ log.error("資料比較出錯"+ e.toString());  e.printStackTrace();}return compareFile;}