android 文件操作

package com.gcg.egis.utility;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class FileHelper {
	
	/**
	 * 删除指定的文件
	 * @param fileName
	 */
	public static void deleteFile(String fileName){
		File file = new File(fileName);
		if(file.isDirectory()){
			String[] files = file.list();
			for (int i = 0; i < files.length; i++) {
				new File(fileName,files[i]).delete();
			}
		}else{
			file.delete();
		}
	}
	
	/**
	 * 保存指定的data内容到指定的文件中
	 * @param data
	 * @param fileName
	 */
	public static void saveFile(byte[] data,String fileName){
		OutputStream os=null;
		try {
			File dir = new File(PARAM.SDCARD_PATH);
			if(!dir.exists()){
				dir.mkdirs();
			}
			File file = new File(fileName);
			if(!file.exists())
				file.createNewFile();
			os = new FileOutputStream(file);
			os.write(data, 0, data.length);
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			try {
				if(os!=null){
					os.close();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
	
	public static byte[] readImageByte(String imagePath){
		byte[] tmp = new byte[4096]; 
		
		ByteArrayOutputStream buffer = new ByteArrayOutputStream();
		InputStream in = null;
		try {
			in = new FileInputStream(imagePath);
			int len;
			while((len = in.read(tmp)) != -1){
				buffer.write(tmp,0,len);
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			try {
				if(in != null)
				in.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return  buffer.toByteArray();
	}

}