这是我生成xml签名的代码:DOMSignContextdsc=newDOMSignContext(prk,xmldoc.getDocumentElement());XMLSignatureFactoryfac=XMLSignatureFactory.getInstance("DOM");DigestMethoddigestMethod=fac.newDigestMethod("http://www.w3.org/2000/09/xmldsig#sha1",null);C14NMethodParameterSpecspec=null;CanonicalizationMethodcm=f