Java method to determine whether a file has been updated over a period of time

This article illustrates a Java method for determining whether a file is updated over a period of time. Share with you for your reference. The specific implementation method is as follows:

Timer 1.

private Timer timer;  

  

/** 

*  Simple timer  

* @param delay   How long before the implementation. ms  

* @param period  Time between executions. ms  

*/  

public void test(long delay, long period) {  

        timer = new Timer();  

        timer.schedule(new TimerTask() {  

            public void run() {  

                //How you do it & NBSP; < br / >
                System.out.println(System.currentTimeMillis());  

            }  

        }, delay, period);  

}

2. Deepen the version

package classloader;  

/** 

 * @author vma 

 */  

//Customize a classloader & NBSP; < br / >
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;  

    //Load the class, if the class file has been loaded, if not, return the current & NBSP; < br / >
    public Class loadClass(String name) throws ClassNotFoundException, IOException{  

     if (isClassModified(name)){  

        dc =  new DynamicClassLoader();  

      return c = dc.findClass(getBytes(name));  

     }  

     return c;  

    }  

    //Whether the judgment has been modified & NBSP; < br / >
    private boolean isClassModified(String filename) {  

        boolean returnValue = false;  

        File file = new File(filename);  

        if (file.lastModified() > lastModified) {  

            returnValue = true;  

        }  

        return returnValue;  

    }  

       //Reading the file locally & NBSP; < br / >
       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. The method of the thread

class Thread1 extends Thread{

  public void run(){

//Invoke the business method (to see if the file has changed) 

Thread.currentThread().sleep("100000");

}

I hope this article has been helpful to your Java programming.