org.springframework.http.MediaType#isWildcardSubtype ( )源码实例Demo

/**
 * Add default headers to the output message.
 * <p>This implementation delegates to {@link #getDefaultContentType(Object)} if a content
 * type was not provided, calls {@link #getContentLength}, and sets the corresponding headers
 * @since 4.2
 */
protected void addDefaultHeaders(HttpHeaders headers, T t, MediaType contentType) throws IOException{
	if (headers.getContentType() == null) {
		MediaType contentTypeToUse = contentType;
		if (contentType == null || contentType.isWildcardType() || contentType.isWildcardSubtype()) {
			contentTypeToUse = getDefaultContentType(t);
		}
		else if (MediaType.APPLICATION_OCTET_STREAM.equals(contentType)) {
			MediaType mediaType = getDefaultContentType(t);
			contentTypeToUse = (mediaType != null ? mediaType : contentTypeToUse);
		}
		if (contentTypeToUse != null) {
			headers.setContentType(contentTypeToUse);
		}
	}
	if (headers.getContentLength() == -1) {
		Long contentLength = getContentLength(t, headers.getContentType());
		if (contentLength != null) {
			headers.setContentLength(contentLength);
		}
	}
}
 

private MediaType getContentType(@Nullable MediaType contentType) {
	if (contentType == null || contentType.isWildcardType() || contentType.isWildcardSubtype()) {
		contentType = getDefaultContentType();
	}
	Assert.notNull(contentType, "Could not select Content-Type. " +
			"Please specify one through the 'defaultContentType' property.");
	return contentType;
}
 

private MediaType getContentType(@Nullable MediaType contentType) {
	if (contentType == null || contentType.isWildcardType() || contentType.isWildcardSubtype()) {
		contentType = getDefaultContentType();
	}
	Assert.notNull(contentType, "Could not select Content-Type. " +
			"Please specify one through the 'defaultContentType' property.");
	return contentType;
}
 

private MediaType getContentType(MediaType contentType) {
	if (contentType == null || contentType.isWildcardType() || contentType.isWildcardSubtype()) {
		contentType = getDefaultContentType();
	}
	Assert.notNull(contentType, "Could not select Content-Type. " +
			"Please specify one through the 'defaultContentType' property.");
	return contentType;
}
 

private void writeInternal(BufferedImage image, MediaType contentType, HttpHeaders headers,
		OutputStream body) throws IOException, HttpMessageNotWritableException {

	if (contentType == null || contentType.isWildcardType() || contentType.isWildcardSubtype()) {
		contentType = getDefaultContentType();
	}
	Assert.notNull(contentType,
			"Count not determine Content-Type, set one using the 'defaultContentType' property");
	headers.setContentType(contentType);
	ImageOutputStream imageOutputStream = null;
	ImageWriter imageWriter = null;
	try {
		Iterator<ImageWriter> imageWriters = ImageIO.getImageWritersByMIMEType(contentType.toString());
		if (imageWriters.hasNext()) {
			imageWriter = imageWriters.next();
			ImageWriteParam iwp = imageWriter.getDefaultWriteParam();
			process(iwp);
			imageOutputStream = createImageOutputStream(body);
			imageWriter.setOutput(imageOutputStream);
			imageWriter.write(null, new IIOImage(image, null, null), iwp);
		}
		else {
			throw new HttpMessageNotWritableException(
					"Could not find javax.imageio.ImageWriter for Content-Type [" + contentType + "]");
		}
	}
	finally {
		if (imageWriter != null) {
			imageWriter.dispose();
		}
		if (imageOutputStream != null) {
			try {
				imageOutputStream.close();
			}
			catch (IOException ex) {
				// ignore
			}
		}
	}
}