Android 追加和覆盖两种方式将byte[]写入文件

ゝ一纸荒年。 2022-06-06 04:27 1266阅读 0赞

/  
\* 此方法为android程序写入sd文件文件，用到了android-annotation的支持库@  
\*  
\* @param buffer 写入文件的内容  
\* @param folder 保存文件的文件夹名称,如log；可为null，默认保存在sd卡根目录  
\* @param fileName 文件名称，默认app\_log.txt  
\* @param append 是否追加写入，true为追加写入，false为重写文件  
\* @param autoLine 针对追加模式，true为增加时换行，false为增加时不换行  
\*/  
public synchronized static void writeFileToSDCard(@NonNull final byte\[\] buffer, @Nullable final String folder,  
@Nullable final String fileName, final boolean append, final boolean autoLine) \{  
new Thread(new Runnable() \{  
@Override  
public void run() \{  
boolean sdCardExist = Environment.getExternalStorageState().equals(  
android.os.Environment.MEDIA\_MOUNTED);  
String folderPath = "";  
if (sdCardExist) \{  
//TextUtils为android自带的帮助类  
if (TextUtils.isEmpty(folder)) \{  
//如果folder为空，则直接保存在sd卡的根目录  
folderPath = Environment.getExternalStorageDirectory()  
\+ File.separator;  
\} else \{  
folderPath = Environment.getExternalStorageDirectory()  
\+ File.separator + folder + File.separator;  
\}  
\} else \{  
return;  
\}  
  
  
File fileDir = new File(folderPath);  
if (!fileDir.exists()) \{  
if (!fileDir.mkdirs()) \{  
return;  
\}  
\}  
File file;  
//判断文件名是否为空  
if (TextUtils.isEmpty(fileName)) \{  
file = new File(folderPath + "app\_log.txt");  
\} else \{  
file = new File(folderPath + fileName);  
\}  
RandomAccessFile raf = null;  
FileOutputStream out = null;  
try \{  
if (append) \{  
//如果为追加则在原来的基础上继续写文件  
raf = new RandomAccessFile(file, "rw");  
raf.seek(file.length());  
raf.write(buffer);  
if (autoLine) \{  
raf.write("\\n".getBytes());  
\}  
\} else \{  
//重写文件，覆盖掉原来的数据  
out = new FileOutputStream(file);  
out.write(buffer);  
out.flush();  
\}  
\} catch (IOException e) \{  
e.printStackTrace();  
\} finally \{  
try \{  
if (raf != null) \{  
raf.close();  
\}  
if (out != null) \{  
out.close();  
\}  
\} catch (IOException e) \{  
e.printStackTrace();  
\}  
\}  
\}  
\}).start();  
\}