<Java> File文件操作

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Java的文件读取使用File类, 进行读取:

exists(): 判断文件存在与否;

createNewFile(): 创建新的文件;

isDirectory(): 是否是文件夹;

FileOutputStream: 写文件;

FileInputStream: 读文件;

import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;public class JavaTest {public static void main(String args[]) {FtDebug.setFileName("test.txt");FtDebug.init();FtDebug.writeLog("this is the first log");FtDebug.close();System.out.println(FtDebug.getContent("test.txt"));}public static class Log {public static void e(String tag, String log) {System.out.println(log);}}public static class FtDebug {private static final String TAG = "DEBUG";private static  String debugFileName = null;private static  String debugFileBakName = null;private static File fileDebug = null;private static FileOutputStream fosDebug = null;public static void setFileName(String name) {debugFileName = name;debugFileBakName = debugFileName + "_bak";}public static boolean init() {if (debugFileName == null) {return false;}if ((fileDebug != null) && fileDebug.exists()) {fileDebug.renameTo(new File(debugFileBakName));// move file to backup file, delete filefileDebug.delete();}fileDebug = new File(debugFileName);try {if (fileDebug.exists()) {fileDebug.renameTo(new File(debugFileBakName));// move file to backup file, delete filefileDebug.delete();}if (!fileDebug.createNewFile()) {Log.e(TAG, "create debug file failed!");return false;}fosDebug = new FileOutputStream(fileDebug);if (fosDebug == null) {Log.e(TAG, "create file output stream failed!");return false;}} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();Log.e(TAG, "create debug file exception!");return false;}return true;}public static void addTimeStamp() {}public static void writeLog(String log) {try {String timeStamp = String.format("<%d>", System.currentTimeMillis());fosDebug.write(timeStamp.getBytes());  // add time stampfosDebug.write(log.getBytes());fosDebug.write(new byte[]{'\r', '\n'});} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();Log.e(TAG, "write file output stream exception!");}}public static void close() {try {fosDebug.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();Log.e(TAG, "close file output stream exception!");}}public static String getContent(String fileName) {File file = new File(fileName);StringBuffer content = new StringBuffer();if (!file.exists()) {return "";}try {FileInputStream fis = new FileInputStream(file);int character;while ( (character = fis.read()) != -1) {content.append((char)character);}fis.close();} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}return content.toString();}}}

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