Question

我正在维护一些旧版Android代码，该代码从文本文件中读取我们产品的“校准”值。从理论上讲，用户可以手动调整校准文件，因此我们每10秒钟重新加载一次文件以检查新值。用户还可以将文件弄乱，因此，如果发现文件不可读/无法解析，我们将写出默认版本的“校准”。

以下是我们阅读和解析术语的相关代码：

public boolean ReadCalibFromFile() {
    boolean res = true;
    String title = null;
    String data = null;
    try {
        File direct = new File(WSDataStorageUtils.getInstance().getCurrentDirLocation());
        if (!direct.exists()) {
            File filesDirectory = new File(WSDataStorageUtils.getInstance().getCurrentDirLocation());
            filesDirectory.mkdirs();
        }
    File calib=new File(new File(WSDataStorageUtils.getInstance().getCurrentDirLocation()), currentCalibFile + ".txt");
    Logger.i(tag, "Using calibration file: " + currentCalibFile + ".txt");
    if(!calib.exists()){
        Logger.i(tag, "Calibration file doesn't exist! Recreating...");
        SaveCalibFiles();

        // having saved the standard files, if we can't find the file we might have a wrong name
        if (!calib.exists()) {
            Logger.e(tag, "This file: " + currentCalibFile + ", doesn't exist, returning to default");
            currentCalibFile = DEFAULT_CALIB_FILE;
            calib=new File(new File(WSDataStorageUtils.getInstance().getCurrentDirLocation()), currentCalibFile + ".txt");
        }

        if (!calib.exists()) { // even after returning to default value
            // we are really screwed
            Logger.e(tag, "Can't even recover to default file! This is bad!");
            return false;
        }
    }
    Scanner read = new Scanner(calib);
    read.useDelimiter("=|\\n");
    while (read.hasNext()) {
        title = read.next();
        data = read.next();
        if (!nextData(data, title)) {
            Logger.e(tag, "Error in reading from Calibration file");
            Logger.e(tag, "title = " + title + " data = " + data);
            res = false;
            break;
        }
    }
    read.close();
    if(VersionChecked == false) {
        res = false;
    }
} catch (Exception e) {
    e.printStackTrace();
    Logger.e("ReadCalibFromfile", "Received an exception: " + e.getMessage());
    StringWriter sw = new StringWriter();
    PrintWriter pw = new PrintWriter(sw);
    e.printStackTrace(pw);
    String stackTrace = sw.toString();
    Logger.e("ReadCalibFromFile", stackTrace);
    Logger.e(tag, "Last good values from file were:");
    Logger.e(tag, "title = " + title + " data = " + data);
    res = false;
}
return res;
}

在大多数情况下，这种方法都能正常工作。我们在周末运行该应用程序（没有人在编辑校准文件），而在深夜，该文件有某种错误。该代码通过覆盖旧文件“修复”了错误-但这是我不理解的错误。

节录的日志：

2018-07-13 00:25:12.441 [Thread-240] INFO  Calibration: Using calibration file: name.txt
2018-07-13 00:25:12.470 [Thread-240] ERROR ReadCalibFromfile: Received an exception: null
2018-07-13 00:25:12.470 [Thread-240] ERROR ReadCalibFromFile: java.util.NoSuchElementException
    at java.util.Scanner.next(Scanner.java:968)
    at java.util.Scanner.next(Scanner.java:941)
    at com.mycompany.myapp.Calibration.ReadCalibFromFile(Calibration.java:190)
    at com.mycompany.myapp.Calibration.run(Calibration.java:108)
    at java.lang.Thread.run(Thread.java:818)

2018-07-13 00:25:12.471 [Thread-240] ERROR Calibration: Last good values from file were:
2018-07-13 00:25:12.471 [Thread-240] ERROR Calibration: title = Version=1.1
firstRegionLimit=8
secondRegionLimit=50
CoafPressRegion0_0=-3.0
CoafPressRegion0_1=3.0
CoafPressRegion0_2=0.01
CoafPressRegion0_3=0.0
CoafPressRegion1_0=1.5
CoafPressRegion1_1=1.4
CoafPressRegion1_2=0.02
CoafPressRegion1_3=0.0
CoafPressRegion2_0=-10.0
CoafPressRegion2_1=5.0
CoafPressRegion2_2=0.015
CoafPressRegion2_3=0.0


*= "   Version : VERSION NUMBER - PLEASE DON'T CHANGE"
*= "   firstRegionLimit :  the high limit of the first range "
*= "   secondRegionLimit : the high limit of the second range "
*= "   mCoafPressRegion :  the coefficient for a certain region "
 data = null

如您所见-尽管分隔符已设置为“ =”和“ \ n”，但该应用程序找不到任何分隔符。需要明确的是，此代码99％的时间都可以在此文件上正常工作。整个第一个“读取”（应该由定界符决定）包含一个包含许多定界符的文本（即使您不相信我每行之间都有真实的'\ n'，也可以看到'='）。

当此函数返回false时，我重写了文件，然后一切正常。...再过几个小时，每10秒钟可以正确读取一次，然后在8个小时多一点后又出现了同样的问题。

还有其他人遇到过这样的问题吗？我不知道这是一个定时问题，因为该文件每10秒读取一次，并且正确关闭了之前的时间。

Scanner.read（）的间歇性错误未拾取定界符

0 个答案: