java利用Timer和TimerTask進行定時調度時，如果碰到TimerTask的任務執行時間多於定時調度的時間頻率則會出現延遲狀況，所以在TimerTask的run方法中通過開闢線程的方法來對任務進行處理，減少了時間延遲帶來的誤差
1. [代碼]每次調度信息都會被顯示在控制檯和被寫到文件裏面，可以直接看控制檯的數據也可以到文件上去查看信息
packagetimer;
importjava.io.File;
importjava.text.SimpleDateFormat;
importjava.util.Date;
importjava.util.TimerTask;
importthread.EventRunnable;
importfile.TxtFileUtil;
publicclass
RunTimerTask extendsTimerTask
{
publicstatic
int
num = 1;
File
file = newFile(
"C:\\Users\\Administrator.BGQJFNVC3FDF6KO\\Desktop\\14.txt"/**
文件路徑名 **/
);
@Override
publicvoid
run() {
doublestartTime
= System.currentTimeMillis();
System.out.println("start");
/**
*
每次調用將日期存入文件中
*/
Date
date = newDate();
SimpleDateFormat
simpleDateFormat = newSimpleDateFormat(
"yyyy-MM-dd
HH:mm:ss");
String
stringDate = simpleDateFormat.format(date);
TxtFileUtil.appendToFile(stringDate
+ "\r\n",
file);
/**
*
每次執行一個時間調度任務時都開闢一個線程去執行，這樣可以減少時間開銷避免任務執行時間過長導致定時調度的延遲
*/
EventRunnable
eventRunnable = newEventRunnable("event"+
num);
Thread
thread = newThread(eventRunnable);
thread.start();
/**
*
算出執行完run方法後消耗的總時間，如果超過一秒則定時器將延遲
*/
doubleendTime
= System.currentTimeMillis();
System.out.println("RunTimerTask"+
num+":"+
(endTime - startTime) + "毫秒");
TxtFileUtil.appendToFile("RunTimerTask"+num
+ ":"+
(endTime - startTime)
+"毫秒"+
"\r\n",
file);
num++;
while(RunTimerTask.num
== 11)
{
this.cancel();
}
}
}
packagethread;
importjava.io.File;
importfile.TxtFileUtil;
publicclass
EventRunnable implementsRunnable
{
privateString
name;
File
file = newFile(
"C:\\Users\\Administrator.BGQJFNVC3FDF6KO\\Desktop\\14.txt"/**
文件路徑名 **/
);
publicEventRunnable(String
name) {
super();
this.name
= name;
}
@Override
publicvoid
run() {
doublestartTime
= System.currentTimeMillis();
String
x = "nihao";
for(inti
= 0;
i < 80000;
i++) {
x
+= "!";
}
doubleendTime
= System.currentTimeMillis();
System.out.println(name
+ ":"+
(endTime - startTime) + "毫秒");
TxtFileUtil.appendToFile(name
+ ":"+
(endTime - startTime) + "毫秒"
+"\r\n",
file);
}
}
packagetimer;
importjava.io.File;
importfile.TxtFileUtil;
importjava.io.ObjectInputStream.GetField;
importjava.sql.Time;
importjava.util.Timer;
publicclass
testTimeTast {
publicstatic
void
main(String[] args) {
File
file = newFile(
"C:\\Users\\Administrator.BGQJFNVC3FDF6KO\\Desktop\\14.txt"/**
*
*
文件路徑名
**/
);
try{
TxtFileUtil.createFile(file);
}catch(Exception
e) {
e.printStackTrace();
}
/**
*
新建一個時間調度任務
*/
RunTimerTask
run = newRunTimerTask();
Timer
timer = newTimer();
timer.schedule(run,0,1000);
}
}
packagefile;
importjava.io.BufferedReader;
importjava.io.BufferedWriter;
importjava.io.File;
importjava.io.FileInputStream;
importjava.io.FileOutputStream;
importjava.io.FileReader;
importjava.io.FileWriter;
importjava.io.IOException;
importjava.math.BigInteger;
importjava.security.MessageDigest;
/**
*
*
@author nyc
*
*
用於讀寫txt文件的工具類
*/
publicclass
TxtFileUtil {
/**
*
創建文件
*
*
@param txtFile
*
@return
*/
publicstatic
boolean
createFile(File txtFile) throwsException
{
booleanflag
= false;
try{
if(!txtFile.exists())
{
txtFile.createNewFile();
flag
= true;
}
}catch(Exception
e) {
e.printStackTrace();
}
returnflag;
}
/**
*
讀TXT文件內容
*
*
@param txtFile
*
@return
*/
publicstatic
String readTxtFile(File txtFile) throwsException
{
String
result = "";
FileReader
fileReader = null;
BufferedReader
bufferedReader = null;
try{
fileReader
= newFileReader(txtFile);
bufferedReader
= newBufferedReader(fileReader);
try{
String
read = null;
while((read
= bufferedReader.readLine()) != null)
{
if(!read.equals("\r\n")){
result
= result + read + "\r\n";
}
else{
result=result+read;
}
}
}catch(Exception
e) {
e.printStackTrace();
}
}catch(Exception
e) {
e.printStackTrace();
}finally{
if(bufferedReader
!= null)
{
bufferedReader.close();
}
if(fileReader
!= null)
{
fileReader.close();
}
}
returnresult;
}
publicstatic
boolean
compareFiles(File srcFile, File desFile) {
returngetFileMD5(srcFile).equals(getFileMD5(desFile));
}
privatestatic
String getFileMD5(File file) {
if(!file.isFile()){
returnnull;
}
MessageDigest
digest = null;
FileInputStream
in=null;
bytebuffer[]
= newbyte[1024];
intlen;
try{
digest
= MessageDigest.getInstance("MD5");
in
= newFileInputStream(file);
while((len
= in.read(buffer, 0,1024))
!= -1)
{
digest.update(buffer,0,
len);
}
in.close();
}catch(Exception
e) {
e.printStackTrace();
returnnull;
}
BigInteger
bigInt = newBigInteger(1,
digest.digest());
returnbigInt.toString(16);
}
/**
*
追加到內容到原文件尾部
*
*
@param txtFile
*/
publicstatic
boolean
appendToFile(String content, File txtFile) {
booleanappend
= false;
booleanresult
= false;
try{
if(txtFile.exists())
append
= true;
FileWriter
fw = newFileWriter(txtFile,
append);
BufferedWriter
bf = newBufferedWriter(fw);
bf.append(content);
result
= true;
bf.flush();
bf.close();
}catch(IOException
e) {
e.printStackTrace();
}
returnresult;
}
/**
*
將內容寫到TXT文件，覆蓋原來內容
*
*
@param content
*
：寫入的符串
*
@param txtFile
*
：文本文件
*
@return： 是否寫入成功
*
@throws Exception
*
：拋出異常
*/
publicstatic
boolean
writeTxtFile(String content, File txtFile)
throwsException
{
booleanflag
= false;
FileOutputStream
outStream = null;
try{
outStream
= newFileOutputStream(txtFile);
if(txtFile.exists())
{
txtFile.delete();
}
outStream.write((newString("")).getBytes());
outStream.flush();
outStream.write(content.getBytes("utf8"));
outStream.close();
flag
= true;
}catch(Exception
e) {
e.printStackTrace();
}
returnflag;
}
publicstatic
void
copyFile(File frmFile, File toFile) {
String
content = "";
try{
content
= readTxtFile(frmFile);
if(toFile.exists())
{
toFile.delete();
}
writeTxtFile(content,
toFile);
}catch(Exception
e) {
e.printStackTrace();
}
}
}
