Android 文件读写工具类

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

package com.sy.utils;

import android.content.Context;
import android.os.Environment;
import android.os.StatFs;
import android.util.Log;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
* Created by SY on 2016/5/9.
* 文件读写工具类
*/
public class FileUtils {

private Context context;
private String SDCardPath = Environment.getExternalStorageDirectory().getAbsolutePath();//sd卡路径
private static String SDState = Environment.getExternalStorageState();//SD卡状态

public FileUtils(Context context) {
this.context = context;
}

/**
* 文件存储到/data/data/<packagename>/files/默认目录下
*
* @param fileName
* @param bytes
* @return
*/
public boolean write2CacheFile(String fileName, byte[] bytes) {

FileOutputStream out = null;
BufferedOutputStream bos = null;
try {
out = context.openFileOutput(fileName, Context.MODE_PRIVATE);

bos = new BufferedOutputStream(out);
bos.write(bytes);
bos.flush();
return true;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (bos != null) {
try {
bos.close();
} catch (IOException e) {
e.printStackTrace();
}
}

}
return false;
}

/**
* 向SD卡里写字节
*
* @param path 文件夹目录
* @param file 文件名
* @param data 写入的字节数组
* @return
*/
public static boolean writeBytes(String path, String file, byte[] data) {
FileOutputStream fos = null;
try {
// 拥有足够的容量
if (data.length < getSDFreeSize()) {
createDirectoryIfNotExist(path);
createFileIfNotExist(path + file);

fos = new FileOutputStream(path + File.separator + file);
fos.write(data);
fos.flush();
return true;
}
}catch (Exception e){
Log.e("writeBytes", e.getMessage());
}finally {
if (fos != null) {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return false;
}
}

/**
* 从SD卡里读取字节数组
*
* @param path     目录
* @param fileName 文件名
* @return 返回字节数组，文件不存在返回null
*/
public static byte[] readBytes(String path, String fileName) {
File file = new File(path + File.separator + fileName);
if (!file.exists()) {
return null;
}
InputStream inputStream = null;
try {
inputStream = new BufferedInputStream(new FileInputStream(file));
byte[] data = new byte[inputStream.available()];
inputStream.read(data);
return data;
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (inputStream != null) {
inputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}

/**
* 将一个字节流写入到SD卡文件
*
* @param path     目录路径
* @param fileName 文件名
* @param input    字节流
* @return
*/

public static Boolean write2SDFromInput(String path, String fileName, InputStream input) {
File file = null;
OutputStream output = null;
try {
int size = input.available();
// 拥有足够的容量
if (size < getSDFreeSize()) {
createDirectoryIfNotExist(path);
createFileIfNotExist(path + File.separator + fileName);
file = new File(path + File.separator + fileName);
output = new BufferedOutputStream(new FileOutputStream(file));
byte buffer[] = new byte[1024];
int temp;
while ((temp = input.read(buffer)) != -1) {
output.write(buffer, 0, temp);
}
output.flush();
return true;

}
} catch (IOException e1) {
e1.printStackTrace();
} finally {
try {
if (output != null) {
output.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
return false;
}

/**
* 判断SD卡是否存在
*
* @ return
*/
private static boolean SDCardisExist() {
if (SDState.equals(Environment.MEDIA_MOUNTED)) {
return true;
} else
return false;
}

/**
* 获取SD卡剩余容量大小（单位Byte）
*
* @return
*/
public static long getSDFreeSize() {
//取得SD卡文件路径
File path = Environment.getExternalStorageDirectory();
StatFs sf = new StatFs(path.getPath());
//获取单个数据块的大小(Byte)
long blockSize = sf.getBlockSize();
//空闲的数据块的数量
long freeBlocks = sf.getAvailableBlocks();
//返回SD卡空闲大小
return freeBlocks * blockSize;  //单位Byte
//return (freeBlocks * blockSize)/1024;   //单位KB
//        return (freeBlocks * blockSize) / 1024 / 1024; //单位MB
}

/**
* 获取SD卡总容量大小（单位Byte）
*
* @return
*/
public static long getSDAllSize() {
//取得SD卡文件路径
File path = Environment.getExternalStorageDirectory();
StatFs sf = new StatFs(path.getPath());
//获取单个数据块的大小(Byte)
long blockSize = sf.getBlockSize();
//获取所有数据块数
long allBlocks = sf.getBlockCount();
//返回SD卡大小
return allBlocks * blockSize; //单位Byte
//return (allBlocks * blockSize)/1024; //单位KB
//        return (allBlocks * blockSize) / 1024 / 1024; //单位MB
}

/**
* 如果目录不存在，就创建目录
*
* @param path 目录
* @return
*/
public static boolean createDirectoryIfNotExist(String path) {
File file = new File(path);
//如果文件夹不存在则创建
if (!file.exists() && !file.isDirectory()) {
return file.mkdirs();
} else {
Log.e("目录", "目录存在！");
return false;
}

}

/**
* 如果文件不存在，就创建文件
* @param path 文件路径
* @return
*/
public static boolean createFileIfNotExist(String path) {
File file = new File(path);
try {
if (!file.exists()) {
return file.createNewFile();
} else {
Log.e("文件", "文件存在！");
return false;
}
} catch (Exception e) {
Log.e("error", e.getMessage());
return false;
}
}
}