使用JAXB实现XML转对象导致XXE漏洞防护

不安全写法，存在漏洞：

public static Object convertXmlToObj(Class clazz, String xmlStr)throws Exception {
    JAXBContext context = JAXBContext.newInstance(clazz);
    Unmarshaller unmarshaller = context.createUnmarshaller();
    return unmarshaller.unmarshal(new StringReader(xmlStr));
}

安全写法，漏洞防护：

public static Object xmlToObjectSafe(Class klass, String xml) throws Exception {
    // 将外部实体、参数实体和内联DTD 都设置为false，从而避免XXE漏洞
    SAXParserFactory spf = SAXParserFactory.newInstance();
    spf.setFeature("http://xml.org/sax/features/external-general-entities", false);
    spf.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
    spf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);

    // Do unmarshall operation
    Source xmlSource = new SAXSource(spf.newSAXParser().getXMLReader(), new InputSource(new StringReader(xml)));

    JAXBContext context = JAXBContext.newInstance(klass);
    Unmarshaller unmarshaller = context.createUnmarshaller();
    return unmarshaller.unmarshal(xmlSource);
}

XXE防护官方文档：（包含各种xml转bean防护方法）https://github.com/OWASP/CheatSheetSeries/blob/master/cheatsheets/XML_External_Entity_Prevention_Cheat_Sheet.md

 参考：

          https://www.cnblogs.com/wfzWebSecuity/p/6681114.html
          https://blog.spoock.com/2018/10/23/java-xxe/
          https://blog.csdn.net/SouthWind0/article/details/89455611