您的位置：首页 > 其它

XmlPath语法

2012-05-22 09:45 218 查看

节点的关系：

父（Parent）

子（Children）

同胞（Sibling）

先辈（Ancestor）

后代（Descendant）
路径表达式

nodename　选取此节点的所有子节点

/ 　　　　　从根节点选取

// 　　　　　从匹配选择的当前节点选择文档中的节点，而不考虑它们的位置

. 　　　　　选取当前节点

.. 　　　　　选取当前节点的父节点

@ 　　　　选取属性

谓语（Predicates）

谓语被嵌在方括号中。

/bookstore/book[1]

/bookstore/book[last()]

/bookstore/book[price<10]

通配符

* 匹配任何元素节点

@* 匹配任何属性节点

node() 匹配任何类型的节点

XPath 轴

ancestor 选取当前节点的所有先辈（父、祖父等）

ancestor-or-self 选取当前节点的所有先辈（父、祖父等）以及当前节点本身

attribute 选取当前节点的所有属性

child 选取当前节点的所有子元素。

descendant 选取当前节点的所有后代元素（子、孙等）。

descendant-or-self 选取当前节点的所有后代元素（子、孙等）以及当前节点本身。

following 选取文档中当前节点的结束标签之后的所有节点。

namespace 选取当前节点的所有命名空间节点

parent 选取当前节点的父节点。

preceding 选取文档中当前节点的开始标签之前的所有节点。

preceding-sibling 选取当前节点之前的所有同级节点。

self 选取当前节点。

摘自：http://hi.baidu.com/dming4/blog/item/7f18d1ef1451fde5ce1b3ecf.html

摘自官网：http://www.eclipse.org/eclipselink/api/2.3/org/eclipse/persistence/oxm/annotations/XmlPath.html

@Target(value={FIELD,METHOD})
@Retention(value=RUNTIME)
public @interface XmlPath

XPath based mapping is what allows an existing object model to be mapped to an existing XML schema. The

@XmlPath

annotation is the means by which XPath based mapping is achieved.

Example 1 - Using
@XmlPath
to Add a Grouping Element
Sometimes grouping elements are added to your document to organise data. JAXB has this concept for collection properties in the form of

@XmlElementWrapper

. Here we'll use

@XmlPath

for non-collection properties. In this case we'll nest the billing/shipping address data within the "contact-info" element.

import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
@XmlPath("contact-info/billing-address")
private Address billingAddress;

@XmlPath("contact-info/shipping-address")
private Address shippingAddress;
}

This will produce XML like: <customer> <contact-info> <billing-address> <street>1 Billing Street</street> </billing-address> <shipping-address> <street>2 Shipping Road</street> </shipping-address> </contact-info> </customer>
Example 2 - Using
@XmlPath
to Map by Position
Normally in JAXB elements with the same name must be mapped to a collection property. Using the @XmlPath extension you map non-collection properties to a repeated element by index.

import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
@XmlPath("address[1]")
private Address billingAddress;

@XmlPath("address[2]")
private Address shippingAddress;
}

This will produce XML like: <customer> <address> <street>1 Billing Street</street> </address> <address> <street>2 Shipping Road</street> </address> </customer>
Example 3 - Using
@XmlPath
to Map Two Objects to the Same Node
We have seen how

@XmlPath

can be used to expand the structure by adding a grouping element.

@XmlPath

can also be used to collapse the structure by mapping two objects to the same node.

import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.XmlPath;

@XmlRootElement @XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
@XmlPath(".")
private Address billingAddress;

private Address shippingAddress;
}

This will produce XML like: <customer> <street>1 Billing Street</street> <shippingAddress> <street>2 Shipping Road</street> </shippingAddress> </customer>

Required Element Summary
java.lang.String	value The XPath for this property.

Element Detail

value

public abstractjava.lang.String value

The XPath for this property. A subset of the XPath specification may be used to specify mappings. The following concepts are supported:

Attribute - "@id"
Element - "address"
Element by Position - "address[1]"
Element by Predicate - "address[@type='mailing']"
Element Text - "name/text()"
Text - "text()"
Self - "."
Combination - "personal-info/name[2]/text()"

For namespace qualified nodes, the prefixes defined in the XmlNs annotations can be used to qualify the XPath fragments. Unqualified fragments will assumed to be in the namespace specified using @XmlSchema.

Example
Assuming the following namespace information has been set up using the @XmlSchema annotation:

@XmlSchema(namespace = "http://www.example.org/FOO",
xmlns = {@XmlNs(prefix="ns", namespaceURI="http://www.example.com/BAR")},
elementFormDefault = XmlNsForm.QUALIFIED)
package org.example;

import javax.xml.bind.annotation.*;

Then the following XPath:

@XmlPath("contact-info/ns:address/@id")

Will be qualified as:

contact-info - in "http://www.example.org/FOO" namespace.
address - in "http://www.example.com/BAR" namespace.
@id - in no namespace.

See Also:

XmlSchema

XmlNs

内容来自用户分享和网络整理，不保证内容的准确性，如有侵权内容，可联系管理员处理

标签：

相关文章推荐

新的分享

章节导航