Android入门：实现一个File存储的辅助类

 

File文件存储博客链接：http://blog.csdn.net/xiazdong/article/details/7687439

 

package com.xiazdong.file.util;



import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStream;



import android.content.Context;

import android.os.Environment;



public class FileUtil {

	/**

	 * 保存文本到内存

	 * @param context

	 * @param filename

	 * @param content

	 * @param mode

	 * @throws Exception

	 */

	public static void saveTextInMemory(Context context,String filename,String content,int mode) throws Exception{

		try{

			FileOutputStream out = context.openFileOutput(filename, mode);

			out.write(content.getBytes("UTF-8"));

			out.close();

		}

		catch(Exception e){

			throw new Exception();

		}

	}

	/**

	 * 保存文件到sdcard

	 * @param filename

	 * @param content

	 * @throws Exception

	 */

	public static void saveTextInSdcard(String filename,String content) throws Exception{

		try{

			File f = new File(Environment.getExternalStorageDirectory(),filename);

			FileOutputStream out = new FileOutputStream(f);

			out.write(content.getBytes("UTF-8"));

			out.close();

		}

		catch(Exception e){

			throw new Exception();

		}

	}

	/**

	 * 从内存读取文件

	 * @param filename

	 * @return

	 * @throws Exception

	 */

	public static String loadTextFromSdcard(String filename) throws Exception{

		try{

			File f = new File(Environment.getExternalStorageDirectory(),filename);

			FileInputStream in = new FileInputStream(f);

			byte[]data = read2byte(in);

			return new String(data,"UTF-8");

		}

		catch(Exception e){

			throw new Exception();

		}

	}

	/**

	 * 从sdcard读取文件 

	 * @param context

	 * @param filename

	 * @return

	 * @throws Exception

	 */

	public static String loadTextFromMemory(Context context,String filename) throws Exception{

		try{

			FileInputStream in = context.openFileInput(filename);

			byte[]data = read2byte(in);

			return new String(data,"UTF-8");

		}

		catch(Exception e){

			throw new Exception();

		}

	}

	private static byte[] read2byte(InputStream in) throws IOException {

		byte[] data;

		ByteArrayOutputStream bout = new ByteArrayOutputStream();

		byte[]buf = new byte[1024];

		int len = 0;

		while((len = in.read(buf))!=-1){

			bout.write(buf, 0, len);

		}

		data = bout.toByteArray();

		return data;

	}

}

 

测试代码：

FileUtil.saveTextInSdcard("1.txt","hello");		//将"hello"保存到/mnt/sdcard/1.txt中

String content = FileUtil.loadTextFromSdcard("1.txt");	//读取/mnt/sdcard/1.txt内容

FileUtil.saveTextInMemory(MainActivity.this,"1.txt","hello", Context.MODE_PRIVATE);	//将hello保存到/data/data/package/files/1.txt中

String content = FileUtil.loadTextFromMemory(MainActivity.this, "1.txt");	//读取/data/data/package/files/1.txt内容