java操作txt

从开源中国复制代码，结果上面全部带了行号，很尴尬。写了一个小程序取出行号。顺便复习一下java的文件操作。

public static void main(String[] args) {String filePath = "D:" + File.separator + "1.txt";String filePath1 = "D:" + File.separator + "2.txt";String encoding = "GBK";String txt = "";//读取txttxt = readTxtFile(filePath, encoding);String reg = "[0-9][0-9][0-9]";String[] arr = txt.split(reg);try {//创建txtcreatTxtFile(filePath1);for (int i = 0; i < arr.length; i++) {//写txt writeTxtFile(arr[i], filePath1);}} catch (IOException e) {e.printStackTrace();}}/** * 读取txt */public static String readTxtFile(String filePath, String encoding) {StringBuffer sb = new StringBuffer("");try {File file = new File(filePath);// 判断文件是否存在if (file.isFile() && file.exists()) { // 考虑到编码格式InputStreamReader read = new InputStreamReader(new FileInputStream(file), encoding);BufferedReader bufferedReader = new BufferedReader(read);String lineTxt = null;while ((lineTxt = bufferedReader.readLine()) != null) {// System.out.println(lineTxt);sb.append(lineTxt);}read.close();} else {System.out.println("文件不存在");}} catch (Exception e) {System.out.println("读取文件内容出错");e.printStackTrace();}return sb.toString();}/** * @throws IOException *             创建txt */public static boolean creatTxtFile(String filePath) throws IOException {boolean flag = false;File filename = new File(filePath);/*if (!filename.exists()) {filename.createNewFile();flag = true;}*/if(filename.exists()){filename.delete();}filename.createNewFile();flag = true;return flag;}/** * 写txt */public static boolean writeTxtFile(String newStr, String filePath)throws IOException {// 先读取原有文件内容，然后进行写入操作boolean flag = false;String filein = newStr + "\r\n";String temp = "";FileInputStream fis = null;InputStreamReader isr = null;BufferedReader br = null;FileOutputStream fos = null;PrintWriter pw = null;try {// 文件路径File file = new File(filePath);// 将文件读入输入流fis = new FileInputStream(file);isr = new InputStreamReader(fis);br = new BufferedReader(isr);StringBuffer buf = new StringBuffer();// 保存文件原有的内容for (; (temp = br.readLine()) != null; ) {buf = buf.append(temp);// 行与行之间的分隔符 相当于“\n”buf = buf.append(System.getProperty("line.separator"));}// 新的内容buf.append(filein);fos = new FileOutputStream(file);pw = new PrintWriter(fos);pw.write(buf.toString().toCharArray());pw.flush();flag = true;} catch (IOException e1) {// TODO 自动生成 catch 块throw e1;} finally {if (pw != null) {pw.close();}if (fos != null) {fos.close();}if (br != null) {br.close();}if (isr != null) {isr.close();}if (fis != null) {fis.close();}}return flag;}