/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package jcoapp;
import java.io.*;
import java.text.SimpleDateFormat;
import java.util.*;
/**
*
* @author luolai
*/
public class LogInfo {
public static void main(String[] args) {
String newLog = " Date:" + new Date() + " |";
appendLog(newLog);
}
public static String getCurrentDate() {
SimpleDateFormat sm = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
return sm.format(new Date());
}
public static String strRight(String value) {
return value.substring(value.length() - 2, value.length());
}
public static void appendLog(String newLog) {
Scanner sc = null;
PrintWriter pw = null;
Calendar c = new GregorianCalendar();
File log = new File("log\\loginfo" + String.valueOf(c.get(c.YEAR))
+ strRight("00" + String.valueOf(c.get(c.MONTH)+1)) + strRight("00" + String.valueOf(c.get(c.DAY_OF_MONTH))) + ".log");
try {
if (!log.exists())//如果文件不存在,則新建.
{
File parentDir = new File(log.getParent());
if (!parentDir.exists())//如果所在目錄不存在,則新建.
{
parentDir.mkdirs();
}
log.createNewFile();
}
sc = new Scanner(log);
StringBuilder sb = new StringBuilder();
while (sc.hasNextLine())//先讀出舊文件內容,並暫存sb中;
{
sb.append(sc.nextLine());
sb.append("\r\n");//換行符作爲間隔,掃描器讀不出來,因此要自己添加.
}
sc.close();
pw = new PrintWriter(new FileWriter(log), true);
/*
* A.
*/
pw.println(sb.toString());//,寫入舊文件內容.
/*
* B.
*/
pw.println(newLog + " [" + getCurrentDate() + "]");//寫入新日誌.
/*
* 如果先寫入A,最近日誌在文件最後. 如是先寫入B,最近日誌在文件最前.
*/
pw.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
public static void appendLog(String logFileName,String newLog) {
Scanner sc = null;
PrintWriter pw = null;
Calendar c = new GregorianCalendar();
File log = new File("log\\"+logFileName + String.valueOf(c.get(c.YEAR))
+ strRight("00" + String.valueOf(c.get(c.MONTH)+1)) + strRight("00" + String.valueOf(c.get(c.DAY_OF_MONTH))) + ".log");
try {
if (!log.exists())//如果文件不存在,則新建.
{
File parentDir = new File(log.getParent());
if (!parentDir.exists())//如果所在目錄不存在,則新建.
{
parentDir.mkdirs();
}
log.createNewFile();
}
sc = new Scanner(log);
StringBuilder sb = new StringBuilder();
while (sc.hasNextLine())//先讀出舊文件內容,並暫存sb中;
{
sb.append(sc.nextLine());
sb.append("\r\n");//換行符作爲間隔,掃描器讀不出來,因此要自己添加.
}
sc.close();
pw = new PrintWriter(new FileWriter(log), true);
/*
* A.
*/
pw.println(sb.toString());//,寫入舊文件內容.
/*
* B.
*/
pw.println(newLog + " [" + getCurrentDate() + "]");//寫入新日誌.
/*
* 如果先寫入A,最近日誌在文件最後. 如是先寫入B,最近日誌在文件最前.
*/
pw.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
java保存日誌到本地文本文件
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