Trail: Java Architecture for XML Binding (JAXB)
Lesson: Introduction to JAXB

绑定 XML 模式

This section describes the default XML-to-Java bindings used by JAXB. All of these bindings can be overridden globally or case-by-case by using a custom binding declaration. See the JAXB Specification for complete information about the default JAXB bindings.

Simple Type Definitions

A schema component using a simple type definition typically binds to a Java property. Because there are different kinds of schema components, the following Java property attributes (common to the schema components) include:

Base type
Collection type, if any
Predicate

The rest of the Java property attributes are specified in the schema component using the simple type definition.

Default Data Type Bindings

The following sections explain the default schema-to-Java, JAXBElement, and Java-to-schema data type bindings.

Schema-to-Java Mapping

The Java language provides a richer set of data types than the XML schema. The following table provides a mapping of XML data types to Java data types in JAXB.

Table: JAXB Mapping of XML Schema Built-in Data Types

XML Schema Type	Java Data Type
`xsd:string`	`java.lang.String`
`xsd:integer`	`java.math.BigInteger`
`xsd:int`	`int`
`xsd.long`	`long`
`xsd:short`	`short`
`xsd:decimal`	`java.math.BigDecimal`
`xsd:float`	`float`
`xsd:double`	`double`
`xsd:boolean`	`boolean`
`xsd:byte`	`byte`
`xsd:QName`	`javax.xml.namespace.QName`
`xsd:dateTime`	`javax.xml.datatype.XMLGregorianCalendar`
`xsd:base64Binary`	`byte[]`
`xsd:hexBinary`	`byte[]`
`xsd:unsignedInt`	`long`
`xsd:unsignedShort`	`int`
`xsd:unsignedByte`	`short`
`xsd:time`	`javax.xml.datatype.XMLGregorianCalendar`
`xsd:date`	`javax.xml.datatype.XMLGregorianCalendar`
`xsd:g`	`javax.xml.datatype.XMLGregorianCalendar`
`xsd:anySimpleType`	`java.lang.Object`
`xsd:anySimpleType`	`java.lang.String`
`xsd:duration`	`javax.xml.datatype.Duration`
`xsd:NOTATION`	`javax.xml.namespace.QName`

`JAXBElement` Object

When XML element information cannot be inferred by the derived Java representation of the XML content, a JAXBElement object is provided. This object has methods to get and set the object name and object value.

Java-to-Schema Mapping

The following table shows the default mapping of Java classes to XML data types.

Table: JAXB Mapping of XML Data Types to Java Classes

Java Class	XML Data Type
`java.lang.String`	`xs:string`
`java.math.BigInteger`	`xs:integer`
`java.math.BigDecimal`	`xs:decimal`
`java.util.Calendar`	`xs:dateTime`
`java.util.Date`	`xs:dateTime`
`javax.xml.namespace.QName`	`xs:QName`
`java.net.URI`	`xs:string`
`javax.xml.datatype.XMLGregorianCalendar`	`xs:anySimpleType`
`javax.xml.datatype.Duration`	`xs:duration`
`java.lang.Object`	`xs:anyType`
`java.awt.Image`	`xs:base64Binary`
`javax.activation.DataHandler`	`xs:base64Binary`
`javax.xml.transform.Source`	`xs:base64Binary`
`java.util.UUID`	`xs:string`