Java斷定時光段內文件能否更新的辦法

Java斷定時光段內文件能否更新的辦法。本站提示廣大學習愛好者：（Java斷定時光段內文件能否更新的辦法）文章只能為提供參考，不一定能成為您想要的結果。以下是Java斷定時光段內文件能否更新的辦法正文

---

本文實例講述了Java斷定時光段內文件能否更新的辦法。分享給年夜家供年夜家參考。詳細完成辦法以下：

1.准時器
private Timer timer; 
 
/**
* 簡略單純准時器
* @param delay  多久後開端履行。毫秒
* @param period 履行的距離時光。毫秒
*/ 
public void test(long delay, long period) { 
        timer = new Timer(); 
        timer.schedule(new TimerTask() { 
            public void run() { 
                //你 的 操作辦法 
                System.out.println(System.currentTimeMillis()); 
            } 
        }, delay, period); 
}

2.深化版
package classloader; 
/**
 * @author vma
 */ 
// 自界說一個類加載器 
public class DynamicClassLoader extends ClassLoader { 
    public Class<?> findClass(byte[] b) throws ClassNotFoundException { 
        return defineClass(null, b, 0, b.length); 
    } 

package classloader; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
/**
 * @author vma
 */ 
public class ManageClassLoader { 
    DynamicClassLoader dc =null; 

    Long lastModified = 0l; 
    Class c = null; 
    //加載類， 假如類文件修正過加載，假如沒有修正，前往以後的 
    public Class loadClass(String name) throws ClassNotFoundException, IOException{ 
     if (isClassModified(name)){ 
        dc =  new DynamicClassLoader(); 
      return c = dc.findClass(getBytes(name)); 
     } 
     return c; 
    } 
    //斷定能否被修正過 
    private boolean isClassModified(String filename) { 
        boolean returnValue = false; 
        File file = new File(filename); 
        if (file.lastModified() > lastModified) { 
            returnValue = true; 
        } 
        return returnValue; 
    } 
       // 從當地讀取文件 
       private byte[] getBytes(String filename) throws IOException { 
        File file = new File(filename); 
        long len = file.length(); 
        lastModified = file.lastModified(); 
        byte raw[] = new byte[(int) len]; 
        FileInputStream fin = new FileInputStream(file); 
        int r = fin.read(raw); 
        if (r != len) {
            throw new IOException("Can't read all, " + r + " != " + len);
        }
        fin.close();
        return raw;
    }
}

3.thread辦法
class Thread1 extends Thread{
  public void run(){
//挪用營業辦法（檢查文件能否轉變）
Thread.currentThread().sleep("100000");
}

願望本文所述對年夜家的Java法式設計有所贊助。

bsp;  @Override
    public void run() {
        for (int i = 0; i < 10; i++) {
            System.out.printf("%s\n", new Date());
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {
                System.out.printf("The FileClock has been interrupted.\n");
            }
        }
    }

FileMain類的完全代碼

package com.diguage.books.concurrencycookbook.chapter1.recipe5;

import java.util.concurrent.TimeUnit;

/**
 * 演示線程休眠和恢復
 * Date: 2013-09-19
 * Time: 00:29
 */
public class FileMain {
    public static void main(String[] args) {
        FileClock clock = new FileClock();
        Thread thread = new Thread(clock);
        thread.start();

        try {
            TimeUnit.SECONDS.sleep(5);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        thread.interrupt();
    }
}