声明抛出 IOException 的 Java 方法不将异常传播到调用堆栈

Question

方法如下：

(388) protected String getExtension(BufferedInputStream stream) throws IOException, MimeTypeException {
(389)   TikaConfig config = TikaConfig.getDefaultConfig();
(390)   MediaType mediaType = config.getMimeRepository().detect(stream, new Metadata());
(391)   MimeType mimeType = config.getMimeRepository().forName(mediaType.toString());
(392)   String extension = mimeType.getExtension(); 
(393)   return extension;
(394) }

这是堆栈：

java.io.IOException: The process cannot access the file because another process has locked a portion of the file
The process cannot access the file because another process has locked a portion of the file
    at java.base/java.io.FileInputStream.readBytes(Native Method)
    at java.base/java.io.FileInputStream.read(FileInputStream.java:328)
    at java.base/java.io.BufferedInputStream.fill(BufferedInputStream.java:291)
    at java.base/java.io.BufferedInputStream.read1(BufferedInputStream.java:347)
    at java.base/java.io.BufferedInputStream.implRead(BufferedInputStream.java:420)
    at java.base/java.io.BufferedInputStream.read(BufferedInputStream.java:399)
    at java.base/java.io.FilterInputStream.read(FilterInputStream.java:95)
    at org.apache.tika.mime.MimeTypes.readMagicHeader(MimeTypes.java:325)
    at org.apache.tika.mime.MimeTypes.detect(MimeTypes.java:527)
    at com.mbm.mediaorganizer.RelocateFileVisitor.getExtension(RelocateFileVisitor.java:390)
    at com.mbm.mediaorganizer.RelocateFileVisitor.relocateFile(RelocateFileVisitor.java:163)
    at com.mbm.mediaorganizer.RelocateFileVisitor.visitFile(RelocateFileVisitor.java:79)
    at com.mbm.mediaorganizer.RelocateFileVisitor.visitFile(RelocateFileVisitor.java:1)
    at java.base/java.nio.file.Files.walkFileTree(Files.java:2810)
    at java.base/java.nio.file.Files.walkFileTree(Files.java:2881)
    at com.mbm.mediaorganizer.MediaOrganizer.run(MediaOrganizer.java:214)
    at com.mbm.mediaorganizer.MediaOrganizer.main(MediaOrganizer.java:63)

从调用堆栈中，您可以看到在进入公开可用的 jar 文件之前执行的最后一行代码是：

(RelocateFileVisitor.java:390)

但是我的代码中的第 390 行位于一个声明它的方法中

throws IOException

。 为什么执行在第 390 行停止并且没有渗透到调用堆栈？

Answer 1

您误读了堆栈跟踪。异常已传播。