android 文件读写工具类

将可以序列化的对象通过base64编码后进行保存

但是感觉多数情况下，不需要采用这个功能，直接保存原始的json字符串，取出来之后再进行解析即可

package com.wotlab.home.moneyplantairs.utils;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;
import java.util.ArrayList;
import java.util.HashMap;

import android.annotation.SuppressLint;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.util.Base64;

public class FileManager {
    /**
     * 将由网络获取的0点开始的等级数据封装成的ArrayTypeMap对象保存到sp文件中
     * 
     * @param arrayMap
     * @param sp
     * @throws IOException
     */
    @SuppressLint("NewApi")
    public static void saveInfo(ArrayMapType arrayMap, SharedPreferences sp,
            String key) throws IOException {
        // 这个需要将请求到的数据保存到sp文件当中
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream os = new ObjectOutputStream(bos);
        os.writeObject(arrayMap);
        // 编码是将字符数组编码为字符串
        String stringBase64 = new String(Base64.encodeToString(
                bos.toByteArray(), Base64.DEFAULT));
        Editor editor = sp.edit();
        editor.putString(key, stringBase64);
        editor.commit();
    }

    @SuppressLint("NewApi")
    /**
     * 从sp文件中读取信息，返回ArrayList<HashMap<String,String>>类型的数据
     * @param sp sp文件
     * @param key sp文件中存储对象的key值
     * @return
     * @throws StreamCorruptedException
     * @throws IOException
     * @throws ClassNotFoundException
     */
    public static ArrayList<HashMap<String, String>> readInfo(
            SharedPreferences sp, String key) throws StreamCorruptedException,
            IOException, ClassNotFoundException {
        String stringBase64 = sp.getString(key, null);
        // 进行对应的解码，
        byte[] bytesBase64 = Base64.decode(stringBase64.getBytes(),
                Base64.DEFAULT);
        ByteArrayInputStream bais = new ByteArrayInputStream(bytesBase64);
        ObjectInputStream ois = new ObjectInputStream(bais);
        ArrayMapType arrayMap = (ArrayMapType) ois.readObject();
        return arrayMap.list;
    }

}

 sd卡文件读写工具类

这个类还是有可以改进之处的

package com.wotlab.home.moneyplantairs.utils;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;

import android.content.Context;
import android.os.Environment;

public class SDFileUtils {
    private String SDPATH; // 用于存sd card的文件的路径   

    public String getSDPATH() {
        return SDPATH;
    }

    public void setSDPATH(String sDPATH) {
        SDPATH = sDPATH;
    }

    /**
     *  构造方法,获取SD卡路径
     */
    public SDFileUtils() {
        // 获得当前外部存储设备的目录 
        SDPATH = Environment.getExternalStorageDirectory() + "/";
    }

    /**
     * 在SD卡上创建文件
     * 
     * @throws IOException
     **/
    public File createSDFile(String fileName) throws IOException {
        File file = new File(SDPATH + fileName);
        file.createNewFile();
        return file;
    }

    /**
     * 在SD卡上创建目录   
     */
    public File createSDDir(String dirName) {
        File dir = new File(SDPATH + dirName);
        System.out.println("storage device's state :"
                + Environment.getExternalStorageState());
        if (Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED)) {
            System.out.println("this directory real path is:"
                    + dir.getAbsolutePath());
            System.out.println("the result of making directory:" + dir.mkdir());
        }
        return dir;
    }

    /**
     *  判断SD卡上的文件夹是否存在
     **/
    public boolean isFileExist(String fileName) {
        File file = new File(SDPATH + fileName);
        return file.exists();
    }

    /**
     *  将一个inputSteam里面的数据写入到SD卡中   
     **/
    public File write2SDFromInput(String path, String fileName,
            InputStream inputStream) {
        File file = null;
        OutputStream output = null;
        try {

            File tempf = createSDDir(path);
            System.out.println("directory in the sd card:" + tempf.exists());
            file = createSDFile(path + fileName);
            System.out.println("file in the sd card:" + file.exists());
            output = new FileOutputStream(file);
            byte buffer[] = new byte[4 * 1024];
            while ((inputStream.read(buffer)) != -1) {
                output.write(buffer);
            }
            output.flush();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                output.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return file;
    }
}

从asserts目录下读取文件的工具类

private String readAsserts(String fileName) {

        StringBuilder stringBuilder = new StringBuilder();
        try {
            BufferedReader bf = new BufferedReader(new InputStreamReader(
                    getAssets().open(fileName)));
            String line;
            while ((line = bf.readLine()) != null) {
                stringBuilder.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return stringBuilder.toString();
    }