getCacheDir()方法用于获取/data/data//cache目录

getFilesDir()方法用于获取/data/data//files目录

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将文件写入SD卡内:

获取SDCard的状态：

Environment.getExtemalStorageState()

Environment.MEDIA_MOUNTED手机装有SDCard,并且可以进行读写

获取SDCard的目录:Environment.getExtemalStorageDirectory()

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File saveFile=new File("/sdcard/zhzhg.txt");

或:File sdCardDir=new File("/sdcard");//获取SD卡目录

File saveFile = new File(sdCardDir,"zhzhg.txt");

FileOutputStream outStream = new FileOutputStream(saveFile);

outStream.write("文件的读写".getBytes());

outStream.close();