spring 源码分析

检验 xml scheme 是dtd 还是XSD

XmlValidationModeDetector

public class XmlValidationModeDetector {

	/**
	 * Indicates that the validation should be disabled.
	 */
	public static final int VALIDATION_NONE = 0;

	/**
	 * Indicates that the validation mode should be auto-guessed, since we cannot find
	 * a clear indication (probably choked on some special characters, or the like).
	 */
	public static final int VALIDATION_AUTO = 1;

	/**
	 * Indicates that DTD validation should be used (we found a "DOCTYPE" declaration).
	 */
	public static final int VALIDATION_DTD = 2;

	/**
	 * Indicates that XSD validation should be used (found no "DOCTYPE" declaration).
	 */
	public static final int VALIDATION_XSD = 3;


	/**
	 * The token in a XML document that declares the DTD to use for validation
	 * and thus that DTD validation is being used.
	 */
	private static final String DOCTYPE = "DOCTYPE";

	/**
	 * The token that indicates the start of an XML comment.
	 */
	private static final String START_COMMENT = "<!--";

	/**
	 * The token that indicates the end of an XML comment.
	 */
	private static final String END_COMMENT = "-->";


	/**
	 * Indicates whether or not the current parse position is inside an XML comment.
	 */
	private boolean inComment;

看代码 判断很简单 有doctype 为dtd

没有为xsd

	public int detectValidationMode(InputStream inputStream) throws IOException {
		// Peek into the file to look for DOCTYPE.
		BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
		try {
			boolean isDtdValidated = false;
			String content;
			while ((content = reader.readLine()) != null) {
				content = consumeCommentTokens(content);
				if (this.inComment || !StringUtils.hasText(content)) {
					continue;
				}
				if (hasDoctype(content)) {
					isDtdValidated = true;
					break;
				}
				if (hasOpeningTag(content)) {
					// End of meaningful data...
					break;
				}
			}
			return (isDtdValidated ? VALIDATION_DTD : VALIDATION_XSD);
		}
		catch (CharConversionException ex) {
			// Choked on some character encoding...
			// Leave the decision up to the caller.
			return VALIDATION_AUTO;
		}
		finally {
			reader.close();
		}
	}