前言:
这周忙的连滚带爬的,终于在周末前把项目完工了。这次主要做的是一个UDP协议的转发器,是一个纯java写的程序,没有任何的框架在里面。其中为了保留住传进来的数据,我们用TXT文本记录下这些数据。文件代码传上来,需要的朋友直接下载就可以用。
代码:
import java.io.*;/** *//** * * 功能描述:创建TXT文件并进行读、写、修改操作 * * @author KenZhang * @version 1.0 * Creation date: 2007-12-18 - 下午06:48:45 */public class ReadWriteFile { public static BufferedReader bufread; //指定文件路径和名称 private static String path = "D:/suncity.txt"; private static File filename = new File(path); private static String readStr =""; /** *//** * 创建文本文件. * @throws IOException * */ public static void creatTxtFile() throws IOException{ if (!filename.exists()) { filename.createNewFile(); System.err.println(filename + "已创建!"); } } /** *//** * 读取文本文件. * */ public static String readTxtFile(){ String read; FileReader fileread; try { fileread = new FileReader(filename); bufread = new BufferedReader(fileread); try { while ((read = bufread.readLine()) != null) { readStr = readStr + read+ "\r\n"; } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } catch (FileNotFoundException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("文件内容是:"+ "\r\n" + readStr); return readStr; } /** *//** * 写文件. * */ public static void writeTxtFile(String newStr) throws IOException{ //先读取原有文件内容,然后进行写入操作 String filein = newStr + "\r\n" + readStr + "\r\n"; RandomAccessFile mm = null; try { mm = new RandomAccessFile(filename, "rw"); mm.writeBytes(filein); } catch (IOException e1) { // TODO 自动生成 catch 块 e1.printStackTrace(); } finally { if (mm != null) { try { mm.close(); } catch (IOException e2) { // TODO 自动生成 catch 块 e2.printStackTrace(); } } } } /** *//** * 将文件中指定内容的第一行替换为其它内容. * * @param oldStr * 查找内容 * @param replaceStr * 替换内容 */ public static void replaceTxtByStr(String oldStr,String replaceStr) { String temp = ""; try { File file = new File(path); FileInputStream fis = new FileInputStream(file); InputStreamReader isr = new InputStreamReader(fis); BufferedReader br = new BufferedReader(isr); StringBuffer buf = new StringBuffer(); // 保存该行前面的内容 for (int j = 1; (temp = br.readLine()) != null && !temp.equals(oldStr); j++) { buf = buf.append(temp); buf = buf.append(System.getProperty("line.separator")); } // 将内容插入 buf = buf.append(replaceStr); // 保存该行后面的内容 while ((temp = br.readLine()) != null) { buf = buf.append(System.getProperty("line.separator")); buf = buf.append(temp); } br.close(); FileOutputStream fos = new FileOutputStream(file); PrintWriter pw = new PrintWriter(fos); pw.write(buf.toString().toCharArray()); pw.flush(); pw.close(); } catch (IOException e) { e.printStackTrace(); } } /** *//** * main方法测试 * @param s * @throws IOException */ public static void main(String[] s) throws IOException { ReadWriteFile.creatTxtFile(); ReadWriteFile.readTxtFile(); ReadWriteFile.writeTxtFile("20080808:12:13");// ReadWriteFile.replaceTxtByStr("ken", "zhang"); } }
清空txt文件的内容:
File f = new File("c:/abc.txt"); FileWriter fw = new FileWriter(f); fw.write("");fw.close();