import org.xerial.snappy.SnappyError; //导入依赖的package包/类
/**
 * Returns the Snappy native library version string without loading the native library.
 * @return Snappy native library version string
 */
public static String getNativeLibraryVersion() {
  URL versionFile = SnappyError.class.getResource("/org/xerial/snappy/VERSION");
  String version = UNKNOWN_VERSION;
  try {
    if (versionFile != null) {
      Properties versionData = new Properties();
      versionData.load(versionFile.openStream());
      version = versionData.getProperty("version", version);
      if (version.equals(UNKNOWN_VERSION)) {
        version = versionData.getProperty("VERSION", version);
      }
      version = version.trim().replaceAll("[^0-9\\.]", "");
    }
  } catch (IOException e) {
  }
  return version;
}
 

import org.xerial.snappy.SnappyError; //导入依赖的package包/类
/**
 * Create a new instance of the SnappyCompressor.
 * 
 * @throws IllegaltStateException when the Snappy native library is unavailable
 */
@SuppressFBWarnings(value="DMI_RANDOM_USED_ONLY_ONCE", justification="The native library is only used once so we only need to generate one random number")
public SnappyCompressor() {
  synchronized (defaultInstance) {
    if (!nativeLibraryLoaded) {
      try {
        SnappyUtils.setSnappySystemProperties(SnappyUtils.getOrCreateLogWriter());
        Snappy.getNativeLibraryVersion();
      } catch (SnappyError se) {
        throw new IllegalStateException(LocalizedStrings.SnappyCompressor_UNABLE_TO_LOAD_NATIVE_SNAPPY_LIBRARY.toLocalizedString(), se);
      }
      nativeLibraryLoaded = true;
    }
  }
}