范围和顺序

javax.xml.XMLConstants#FEATURE_SECURE_PROCESSING (FSP) is a required feature for XML processors including DOM, SAX, Schema Validation, XSLT and XPath. When set to true, it is recommended that implementations enable access restrictions as defined by the new properties specified above. For compatibility, JAXP 1.5 does not enable the new restrictions, although FSP is true by default for DOM, SAX and Schema Validation.

For JDK 8, the new accessExternal* properties are proposed to be set to the empty string when FSP is explicitly set. This is only the case when FSP is set through the API, e.g. factory.setFeature(FSP, true). Although FSP is true by default for DOM, SAX and Schema Validation it is not treated as if "explicitly" set, JDK 8 therefore does not set restrictions by default.

Properties specified in the jaxp.properties file affect all invocations of the JDK or JRE, and will override their default values, or those that may have been set by FEATURE_SECURE_PROCESSING.

System properties, when set, will affect one invocation only, and will override the default settings or those set in jaxp.properties, or those that may have been set by FEATURE_SECURE_PROCESSING.

JAXP properties specified through JAXP factories or SAXParser take preference over system properties, the jaxp.properties file, as well as javax.xml.XMLConstants#FEATURE_SECURE_PROCESSING.

The new JAXP properties have no effect on the relevant constructs they attempt to restrict in the following situations:

• When there is a resolver and the source returned by the resolver is not null. This applies to entity resolvers that may be set on SAX and DOM parsers, XML resolvers on StAX parsers, LSResourceResolver on SchemaFactory, a Validator or ValidatorHandler, or URIResolver on a transformer.
• When a schema is created explicitly by calling SchemaFactory's newSchema method.
• When external resources are not required. For example, the following features/properties are supported by the reference implementation and may be used to instruct the processor to not load the external DTD or resolve external entities.
  

  http://apache.org/xml/features/disallow-doctype-decl true
  http://apache.org/xml/features/nonvalidating/load-external-dtd false
  http://xml.org/sax/features/external-general-entities false
  http://xml.org/sax/features/external-parameter-entities false