Java IO 日志

package com.demo;import java.io.File;import java.io.FileWriter;import java.io.IOException;import java.text.SimpleDateFormat;import java.util.Date;public class MercuryLog {public void writeException(String exceptionStr){SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmmss");String logFileName = "log/"+ dateFormat.format(new Date()) + ".txt";File logDir=new File("log");if(!logDir.exists()){logDir.mkdir();}File f = new File(logFileName);FileWriter fileWriter = null;try {if (!f.exists()) {fileWriter = new FileWriter(logFileName);} else {fileWriter = new FileWriter(f);}fileWriter.write(exceptionStr);} catch (IOException e) {e.printStackTrace();} finally {if (fileWriter != null) {try {fileWriter.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}System.out.println(f.getAbsolutePath());}}