Android文件拷贝

最近项目中协助做了个小的测试程序，需要拷贝文件。代码如下：

    // fixed for raw data test.    private static final String RAW_DATA_TEST = "***123***";    private static final String EXTERNAL_STORAGE = "/mnt/sdcard2";    private static final String INTERNAL_STORAGE = "/mnt/sdcard";        private static final String RAW_DATA_CFG_FILE_NAME = "config.xml";

    // fixed for raw data test.    static public boolean handleRawDataTest(Context context, String input) {        if (RAW_DATA_TEST.equals(input)) {            Log.d(TAG, "handleRawDataTest");            if (!copyRawDataCfgFile()) {                Log.d(TAG, "handleRawDataTest, get Raw Data Cfg file failed!");                Toast.makeText(context,                     context.getString(R.string.raw_data_cfg_file_not_exist),                     Toast.LENGTH_SHORT).show();                return false;            }                        Intent intent = new Intent();            intent.setComponent(new ComponentName("com.goodix.rawdata",                                         "com.goodix.rawdata.RawDataTest"));            context.startActivity(intent);            return true;        }                return false;    }    public static boolean copyRawDataCfgFile() {        String state = Environment.getExternalStorageState();        if (!Environment.MEDIA_MOUNTED.equals(state)) {            return false;        }        String srcFileName = EXTERNAL_STORAGE + File.separator + RAW_DATA_CFG_FILE_NAME;        String destFileName = INTERNAL_STORAGE + File.separator + RAW_DATA_CFG_FILE_NAME;        Log.d(TAG, "copyRawDataCfgFile, srcFileName = " + srcFileName + ", destFileName = " + destFileName);        try {            if (copyFile(srcFileName, destFileName, true)) {                Log.d(TAG, "copyRawDataCfgFile, successfull!");                return true;            }        } catch (Exception e) {            e.printStackTrace();        }        Log.d(TAG, "copyRawDataCfgFile, fail!");        return false;    }    public static boolean copyFile(String srcFileName, String destFileName, boolean reWrite)         throws IOException {        Log.d(TAG, "copyFile, begin");        File srcFile = new File(srcFileName);        File destFile = new File(destFileName);                if(!srcFile.exists()) {            Log.d(TAG, "copyFile, source file not exist.");            return false;        }        if(!srcFile.isFile()) {            Log.d(TAG, "copyFile, source file not a file.");            return false;        }        if(!srcFile.canRead()) {            Log.d(TAG, "copyFile, source file can't read.");            return false;        }        if(destFile.exists() && reWrite){            Log.d(TAG, "copyFile, before copy File, delete first.");            destFile.delete();        }        try {            InputStream inStream = new FileInputStream(srcFile);            FileOutputStream outStream = new FileOutputStream(destFile);            byte[] buf = new byte[1024];            int byteRead = 0;            while ((byteRead = inStream.read(buf)) != -1) {                outStream.write(buf, 0, byteRead);            }            outStream.flush();            outStream.close();            inStream.close();        } catch (IOException e) {            throw e;        } catch (Exception e) {            e.printStackTrace();        }        Log.d(TAG, "copyFile, success");        return true;    }

代码比较简单，但是中间报了个很奇怪的异常，纠结了很长时间，幸好在临下班前找到问题根结所在。记下这次事件，以此勉之。

异常如下：

01-01 00:14:31.070: E/StrictMode(3297): A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.01-01 00:14:31.070: E/StrictMode(3297): java.lang.Throwable: Explicit termination method 'close' not called01-01 00:14:31.070: E/StrictMode(3297): at dalvik.system.CloseGuard.open(CloseGuard.java:184)01-01 00:14:31.070: E/StrictMode(3297): at java.io.FileInputStream.<init>(FileInputStream.java:80)01-01 00:14:31.070: E/StrictMode(3297): at com.android.dialer.SpecialCharSequenceMgr.copyFile(SpecialCharSequenceMgrProxy.java:768)01-01 00:14:31.070: E/StrictMode(3297): at com.android.dialer.SpecialCharSequenceMgr.copyRawDataCfgFile(SpecialCharSequenceMgrProxy.java:702)01-01 00:14:31.070: E/StrictMode(3297): at com.android.dialer.SpecialCharSequenceMgr.handleRawDataTest(SpecialCharSequenceMgrProxy.java:674)01-01 00:14:31.070: E/StrictMode(3297): at com.android.dialer.SpecialCharSequenceMgr.handleCharsForTest(SpecialCharSequenceMgrProxy.java:618)01-01 00:14:31.070: E/StrictMode(3297): at com.android.dialer.SpecialCharSequenceMgr.handleChars(SpecialCharSequenceMgrProxy.java:88)01-01 00:14:31.070: E/StrictMode(3297): at com.android.dialer.dialpad.DialpadFragment.afterTextChanged(DialpadFragment.java:451)01-01 00:14:31.070: E/StrictMode(3297): at android.widget.TextView.sendAfterTextChanged(TextView.java:7626)01-01 00:14:31.070: E/StrictMode(3297): at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:9424)

在网上也搜过“java.io.Closeable for information on avoiding resource leaks”和“java.lang.Throwable: Explicit termination method 'close' not called”，都没找到和我这个问题类似的情况，一般都是cursor导致的内存泄漏的问题。最终，在反复查看代码才发现，原来问题的根结在我拷贝文件的目标目录未指定正确。出现问题的时候，我指定了INTERNAL_STORAGE为“/mnt/sdcard0”，在调用到new FileOutputStream(destFile)时会抛出异常，原因是并没有这个目录。手机内部存储根目录是“/mnt/sdcard”，这个路径实际指向了“/storage/sdcard0”。

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