17370845950

nio使用中的java.nio.file.FileSystemNotFoundException分析析

在使用nio加载文件时,在idea中运行没有问题,但打成jar包后在windows和linux下都有问题:代码语言:javascript代码运行次数:0运行复制

  public static void main(String[] args) throws Exception{        // SpringApplication.run(MarketCollectApplication.class,args);         URI uri = MarketCollectApplication.class.getClassLoader().getResource("conf/sh.txt").toURI();         FileSystem aDefault = FileSystems.getDefault();         System.out.println(aDefault.getClass());         FileSystemProvider provider = FileSystems.getDefault().provider();         System.out.println(provider.getClass());         System.out.println("====================" + uri.getScheme());         List fileSystemProviders = FileSystemProvider.installedProviders();         fileSystemProviders.forEach(p -> {             System.out.println(p.getClass());         });         Path path = Paths.get(uri);     }
这种情况下在idea中没有问题:代码语言:javascript代码运行次数:0运行复制
class sun.nio.fs.WindowsFileSystemclass sun.nio.fs.WindowsFileSystemProvider====================fileclass sun.nio.fs.WindowsFileSystemProviderclass com.sun.nio.zipfs.ZipFileSystemProvider
但是在打成jar包运行时Path path = Paths.get(uri)这一行会抛出异常:windows环境下:
linux环境下:
究其原因,是FileSystemProvider的使用问题,先看java.nio.file.Paths#get(java.net.URI):代码语言:javascript代码运行次数:0运行复制
public static Path get(URI uri) {        String scheme =  uri.getScheme();        if (scheme == null)            throw new IllegalArgumentException("Missing scheme");        // check for default provider to avoid loading of installed providers        if (scheme.equalsIgnoreCase("file"))            return FileSystems.getDefault().provider().getPath(uri);        // try to find provider        for (FileSystemProvider provider: FileSystemProvider.installedProviders()) {            if (provider.getScheme().equalsIgnoreCase(scheme)) {                return provider.getPath(uri);            }        }        throw new FileSystemNotFoundException("Provider \"" + scheme + "\" not installed");    }
uri.getScheme()在idea中是file,在打成jar包后变成了jar。当前缀以file开头时,会使用FileSystems.getDefault().provider()来处理,这个provider在windows环境下是WindowsFileSystemProvider, 在linux环境下是LinuxFileSystemProvider。FileSystemProvider.installedProviders()对应windows中的WindowsFileSystemProvider和ZipFileSystemProvider,对应linux中的LinuxFileSystemProvider和ZipFileSystemProvider。当前缀不以file开头时,会使用FileSystemProvider.installedProviders()中与uri.getScheme()匹配的provider来处理,对应的就是ZipFileSystemProvider。ZipFileSystemProvider对应的FileSystem需要自己创建,使用和创建方式参考:https://docs.oracle.com/javase/8/docs/technotes/guides/io/fsp/zipfilesystemprovider.html解决办法:在Path path = Paths.get(uri)中进行处理代码语言:javascript代码运行次数:0运行复制
    Path path = null;    try{        path = Paths.get(uri);    }catch (Exception e){        //@see https://stackoverflow.com/questions/25032716/getting-filesystemnotfoundexception-from-zipfilesystemprovider-when-creating-a-p        //@see  http://docs.oracle.com/javase/7/docs/technotes/guides/io/fsp/zipfilesystemprovider.html        FileSystem zipfs = FileSystems.newFileSystem(uri, env);        path = Paths.get(uri);    }

或者使用其他办法加载资源文件:

代码语言:javascript代码运行次数:0运行复制
byte[] data;try (InputStream in = getClass().getResourceAsStream("/elasticsearch/segmentsIndex.json")) {    data = IOUtils.toByteArray(in);}
参考:https://stackoverflow.com/questions/25032716/getting-filesystemnotfoundexception-from-zipfilesystemprovider-when-creating-a-p