使用Groovy的XmlSlurper读取XML

此示例假设你已经将如下的类放到你的CLASSPATH中：

XmlExamples.groovy

class XmlExamples {
  static def CAR_RECORDS = '''
    <records>
      <car name='HSV Maloo' make='Holden' year='2006'>
        <country>Australia</country>
        <record type='speed'>Production Pickup Truck with speed of 271kph</record>
      </car>
      <car name='P50' make='Peel' year='1962'>
        <country>Isle of Man</country>
        <record type='size'>Smallest Street-Legal Car at 99cm wide and 59 kg in weight</record>
      </car>
      <car name='Royale' make='Bugatti' year='1931'>
        <country>France</country>
        <record type='price'>Most Valuable Car at $15 million</record>
      </car>
    </records>
  '''
}

此处是XmlSlurper用法的示例：

def records = new XmlSlurper().parseText(XmlExamples.CAR_RECORDS)
def allRecords = records.car
assert 3 == allRecords.size()
def allNodes = records.depthFirst().collect{ it }
assert 10 == allNodes.size()
def firstRecord = records.car[0]
assert 'car' == firstRecord.name()
assert 'Holden' == firstRecord.@make.text()
assert 'Australia' == firstRecord.country.text()
def carsWith_e_InMake = records.car.findAll{ it.@make.text().contains('e') }
assert carsWith_e_InMake.size() == 2
// alternative way to find cars with 'e' in make
assert 2 == records.car.findAll{ it.@make =~ '.*e.*' }.size()
// makes of cars that have an 's' followed by an 'a' in the country
assert ['Holden', 'Peel'] == records.car.findAll{ it.country =~ '.*s.*a.*' }.@make.collect{ it.text() }
def expectedRecordTypes = ['speed', 'size', 'price']
assert expectedRecordTypes == records.depthFirst().grep{ it.@type != '' }.'@type'*.text()
assert expectedRecordTypes == records.'**'.grep{ it.@type != '' }.'@type'*.text()
def countryOne = records.car[1].country
assert 'Peel' == countryOne.parent().@make.text()
assert 'Peel' == countryOne.'..'.@make.text()
// names of cars with records sorted by year
def sortedNames = records.car.list().sort{ it.@year.toInteger() }.'@name'*.text()
assert ['Royale', 'P50', 'HSV Maloo'] == sortedNames
assert ['Australia', 'Isle of Man'] == records.'**'.grep{ it.@type =~ 's.*' }*.parent().country*.text()
assert 'co-re-co-re-co-re' == records.car.children().collect{ it.name()[0..1] }.join('-')
assert 'co-re-co-re-co-re' == records.car.'*'.collect{ it.name()[0..1] }.join('-')

:!: 注意事项：

如果你的XML元素（element，其实就是XML的tag-译者注）中包含想横杠（-）之类的字符，你可以将元素名称用双引号引起来，看如下XML片段：

<foo>
  <foo-bar>test</foo-bar>
</foo>

你可以这样做：

def foo = new XmlSlurper.parseText(FOO_XML)
assert "test" == foo."foo-bar".text()

你也可以处理有命名空间的XML文档，如下：

def wsdl = '''
<definitions name="AgencyManagementService"
    xmlns:ns1="http://www.example.org/NS1"
    xmlns:ns2="http://www.example.org/NS2">
    <ns1:message name="SomeRequest">
        <ns1:part name="parameters" element="SomeReq" />
    </ns1:message>
    <ns2:message name="SomeRequest">
        <ns2:part name="parameters" element="SomeReq" />
    </ns2:message>
</definitions>
'''
 
def xml = new XmlSlurper().parseText(wsdl).declareNamespace(ns1: 'http://www.example.org/NS1', ns2: 'http://www.example.org/NS2')
println xml.'ns1:message'.'ns1:part'.size()
println xml.'ns2:message'.'ns2:part'.size()

XmlSlurper的declareNamespace方法使用一个Map前缀来实现到URI的映射，你只需要声明命名空间并且在GPath表达式中使用此前缀即可，如下：

new XmlSlurper().parseText(blog).declareNamespace(dc: "http://purl.org/dc/elements/1.1/").channel.item.findAll { item ->
   d.any{entry -> item."dc:date".text() =~ entry.key} && a.any{entry -> item.tags.text() =~ entry
}

一些备注:

name或者”*:name”将匹配一个名称为”name”的元素，而不管它的命名空间（这是操作的缺省模式）
”:name”将匹配一个名称为”name”的元素，但元素的id不能有命名空间
“prefix:name”将匹配一个名称为”name”的元素，但只有命名空间是前缀 “prefix” 才行（此前缀到命名空间的映射在前边讨论的declareNamespace中定义）

你可以使用StreamingMarkupBuilder轻松的生成命名空间的元素：

System.out << new StreamingMarkupBuilder().bind {
    mkp.declareNamespace(dc: "http://purl.org/dc/elements/1.1/")
 
    root {
        dc.date()
    }
}