MediaType.java 文件源码

private static MediaType create(String type, String subtype, Multimap<String, String> parameters) {
  checkNotNull(type);
  checkNotNull(subtype);
  checkNotNull(parameters);
  String normalizedType = normalizeToken(type);
  String normalizedSubtype = normalizeToken(subtype);
  checkArgument(!WILDCARD.equals(normalizedType) || WILDCARD.equals(normalizedSubtype),
                "A wildcard type cannot be used with a non-wildcard subtype");
  ImmutableListMultimap.Builder<String, String> builder = ImmutableListMultimap.builder();
  for (Entry<String, String> entry : parameters.entries()) {
    String attribute = normalizeToken(entry.getKey());
    builder.put(attribute, normalizeParameterValue(attribute, entry.getValue()));
  }
  MediaType mediaType = new MediaType(normalizedType, normalizedSubtype, builder.build());
  // Return one of the constants if the media type is a known type.
  return MoreObjects.firstNonNull(KNOWN_TYPES.get(mediaType), mediaType);
}