如何将本地DTD文件的验证应用于java中的xml文件？

I need to parse a bunch of incoming XML documents but it does not contain DTD declaration. Currently I am parsing xml documents using SAX Parser but without DTD validation. Now I want to apply DTD validation. DTD is created by myself. How can I validate an XML file using DTD created by myself (SAX parser) ? I found some tutorials using Transformer but all for DOM Parser. I need to parse a bunch of incoming XML documen