标记输入流并对其进行重置（对于大型文件）时，出现“重置为无效标记”的异常。？

Question

我正在使用输入流对象来计算某个文件的 Md5。我标记流 稍后我重置流。但是，对于大文件，会出现以下异常...

inStreamLatestFile.mark(0);
checkSumCalculated = MD5CheckSumCalculator.calculateMD5CheckSum(inStreamLatestFile);
inStreamLatestFile.reset();

例外情况

.Md5ValidationAggrStrat ||**Error in calculating checksum:: java.io.IOException: Resetting to invalid mark**
                        ||java.io.IOException: Resetting to invalid mark
                        ||at java.io.BufferedInputStream.reset(BufferedInputStream.java:437)
                        ||at com.amadeus.apt.ib.modules.func.map.camel.strategy.Md5ValidationAggrStrategy.aggregate(Md5ValidationAggrStrategy.java:81)
                        ||at org.apache.camel.processor.aggregate.AggregateProcessor.onAggregation(AggregateProcessor.java:365)
                        ||at org.apache.camel.processor.aggregate.AggregateProcessor.doAggregation(AggregateProcessor.java:245)
                        ||at org.apache.camel.processor.aggregate.AggregateProcessor.process(AggregateProcessor.java:201)
                        ||at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61)
                        ||at org.apache.camel.util.AsyncProcessorHelper.process(AsyncProcessorHelper.java:73)

我已经尝试过用这种方式关闭流并重新打开它..只是得到一些如下的异常:

 try {
        inStreamLatestFile= ExchangeHelper.getMandatoryInBody(
                  oldExchange, InputStream.class);

        //inStreamLatestFile.mark(0);
        checkSumCalculated = MD5CheckSumCalculator.calculateMD5CheckSum(inStreamLatestFile);

        //closing the inputStream of the latest file
        if(inStreamLatestFile != null){
            try {
                inStreamLatestFile.close();
            } catch (IOException e) {
                logger.error("Error occurred in closing the stream :: "+ e.getMessage());
            }
        }


        tempInputStream= ExchangeHelper.getMandatoryInBody(
                  oldExchange, InputStream.class);
        oldExchange.getIn().setBody(tempInputStream);

然而，当我尝试重新使用新检索的InputStream时，出现了以下异常。

 caught: java.io.IOException: Stream closed: java.io.IOException: Stream closed
at java.io.BufferedInputStream.getBufIfOpen(BufferedInputStream.java:162)

Answer 1

我假设你使用的是 BufferedInputStream，因为它的源代码为 reset（） 方法

public synchronized void reset() throws IOException {
    getBufIfOpen(); // Cause exception if closed
    if (markpos < 0)
        throw new IOException("Resetting to invalid mark"); // exception you are getting
    pos = markpos;
}

下面的调用

MD5CheckSumCalculator.calculateMD5CheckSum(inStreamLatestFile);

必须对markPos做些什么。

如果您无法控制它，只需重新打开流。如果无法重新打开流，即每次都检索相同的实例，请考虑使用ByteArrayOutputStream

您可以将原始的< code>InputStream读入< code > ByteArrayOutputStream 。将该流中的字节复制到新的< code > bytearrayiputstream 中。把它传给MD5计算器。然后使用相同的字节再次创建一个新的< code > bytearrayiputstream ,并将其传递给任何您需要的对象。