最近要做一个数据发布的客户端，底层用Mina做通信，自定协议，实现传输。在客户端，模仿现在很流行的U盘助手，对U盘的操作进行检测。贴点儿小用例，部分想法来源于互联网，自己小改了下。代码主要通过File类中的listroots对文件系统进行遍历，比较出盘符的变化，进而通过递归遍历出U盘中的内容。

package com.a2.desktop.example1.files.iterator;import java.io.File;import java.util.Vector;/** *  * @author Chen.Hui * @since 2012-10-22 U盘检测程序 */public class DiskSearchThread implements Runnable {	/** root 现有文件系统的盘符 */	private File[] roots = File.listRoots();	/** fileVector 为了遍历U盘内文件 */	private Vector
    
      fileVector = new Vector
     
      ();	volatile boolean sign = false;	SearchFileThread t = null;	public DiskSearchThread() {	}	@Override	public void run() {		System.out.println("Checking System...");		while (true) {			File[] tempFiles = File.listRoots();			fileVector.removeAllElements();			/** 检测到了有U盘插入 */			if (tempFiles.length > roots.length) {				for (int i = tempFiles.length - 1; i >= 0; i--) {					sign = false;					for (int j = roots.length - 1; j >= 0; j--) {						/** 如果前后比较的盘符相同 */						if (tempFiles[i].equals(roots[j])) {							sign = true;						}					}					/** 如果前后比较的盘符不相同，将不相同的盘符写入向量，并做进一步处理 */					if (sign == false) {						fileVector.add(tempFiles[i]);					}				}				roots = File.listRoots();				t = new SearchFileThread(fileVector);				t.start();			} else {				for (int i = roots.length - 1; i >= 0; i--) {					sign = false;					for (int j = tempFiles.length - 1; j >= 0; j--) {						if (tempFiles[j].equals(roots[i])) {							sign = true;						}					}					/** 如果前后比较的盘符不相同，表明U盘被拔出 */					if (sign == false) {						System.out.println("QUIT:" + roots[i].toString());						fileVector.removeAllElements();						t.setIsExistToFalse();						// roots=File.listRoots();					}				}				roots = File.listRoots();			}			try {				Thread.sleep(1000);			} catch (InterruptedException e) {				e.printStackTrace();			}		}	}	public static void main(String[] args) {		new Thread(new DiskSearchThread()).start();	}}
     
    

package com.a2.desktop.example1.files.iterator;import java.io.File;import java.util.Vector;/** *  * @author Chen.Hui * @since 2012-10-22 U盘检测程序 */public class SearchFileThread extends Thread {	private Vector
    
      fileVector = null;	private int scanNum = 1;	/** 线程安全的变量，用于退出线程 */	volatile boolean isExist = true;	public SearchFileThread(Vector
     
       fileVector) {		this.fileVector = fileVector;		System.out.println("fileVector size:" + fileVector.size());	}	@Override	public void run() {		File file = fileVector.elementAt(scanNum - 1);		long totalMemory = file.getFreeSpace();		while (isExist) {			while (scanNum <= fileVector.size()) {				try {					System.out.println("search:"							+ fileVector.elementAt(scanNum - 1).toString()							+ " Total Space:"							+ fileVector.elementAt(scanNum - 1).getTotalSpace()							/ 1024 / 1024 + "MB Free Space:"							+ fileVector.elementAt(scanNum - 1).getFreeSpace()							/ 1024 / 1024 + "MB");					/** 遍历文件内容 */					getFiles(fileVector.elementAt(scanNum - 1).getPath());					scanNum++;				} catch (Exception e) {					e.printStackTrace();					scanNum++;				}			}			/** 如果盘符的大小发生变化，则有文件进出 */			if (totalMemory != file.getFreeSpace()) {				System.out.println("文件发生变化----------------------");				getFiles(file.getPath());				totalMemory = file.getFreeSpace();			}		}	}	public void getFiles(String path) {		try {			File file = new File(path);			if (file.isDirectory()) {				File[] list = file.listFiles();				for (int i = 0; i < list.length; i++) {					if (list[i].isDirectory()) {						/** 递归调用 */						getFiles(list[i].getPath());					}					System.out.println("Find File:" + list[i].getName());				}			}		} catch (Exception e) {			e.printStackTrace();		}	}	public synchronized void setIsExistToFalse() {		if (isExist == true)			isExist = false;	}}
     
    

后续主要还是要做Mina的通信，对于通信的代码，会在之后的文章中贴出。