fileopener.java

1．文件和目录管理

/**
 * Class FileOpener is a class open files.
 * Once used an instance of the class to open a file,
 * you can get the elementary information of the file,
 * and if the file is a foder,you could get the file list of it.
 * 
 * @author  lcw
 */
package file;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
import java.io.IOException;
import java.text.*;
import java.util.*;

public class FileOpener {
    
    private File f;
	private StringBuffer info;
    private String[] fileList;
    
    public FileOpener() {
    	
    	info = new StringBuffer();
    }

    /**
     * method to open file,it may be throws FileNameEmptyException
     * @param fileName is suppose to be the name of the file to open
     * @return a file build on the file name
     */   
    public File openFile(String fileName) throws FileNameEmptyException{
        
        if(fileName.length() == 0) 
        	throw new FileNameEmptyException();
        
        else return new File(fileName);
        
    }
    
    /**
     * method to get the information of a file to be open
     * @param fileName is suppose to be the name of the file to open
     * @return the information as StringBuffer
     */
    public StringBuffer getInfo(String fileName) {
    	
    	try {
    		DateFormat formatter = DateFormat.getInstance();
    		f = openFile(fileName);
    		info.delete(0,info.length());
    		info.append("File :    " + f.getAbsolutePath() + "\n");
    		if(f.exists()){
    
				info.append("exists: true" + "\n");
				info.append("path: " + f.getPath() + "\n");
				info.append("canRead: " + f.canRead() + "\n");    
				info.append("canWrite: " + f.canWrite() + "\n");
				info.append("isHidden: " + f.isHidden() + "\n");
				info.append("lastModified: " + formatter.format(new Date(f.lastModified()))
    					 + "\n");
    			if(f.isFile()) {
    			  				
    				info.append("isFile: " + "true \n");
    				info.append("long: " + f.length() + "\n");
    			}
    			else {
    				
    				info.append("isDirectory: true \n");
    				fileList = f.list();		
    			}

    		}else {
    			
    			info.append("exists: fasle" + "\n");
    		}    		
    	} catch(FileNameEmptyException e) {
    	}finally {
    		return info;
    	}    	
    }
    
    /**
     * method to get the subfiles of a file
     * @return the sub files as if the file is directory.
     */
    public String[] getFileList() {
   	
    	if(f.isFile())
    		return new String[]{"No Files","It's a file"};
    	else return fileList;
    }
    	
}