Android入门：实现一个File存储的辅助类

[java]
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：
[java]
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

作者：xiazdong

补充：移动开发 , Android ,