Xpath expression with multiple predicates

问题

I am trying to build a complex xpath expression which will answer the following condition.

From the XML data below, returns the User entity which:

His loginname is "user1"
His name is "User 1"

He has 2 different profiles values which are "operator" and "admin" (I don't know the exact order ahead)

<user>
  <login>user1</login>
  <name>User 1</name>
  <profile>
    <value>admin</value>
    <id>2</id>
    <description>admin users</description>
  </profile>
  <profile>
    <value>operator</value>  
    <id>1</id>
    <description>Operator</description>
  </profile>
</user>

<user>
  <login>user2</login>
  <name>User 2</name>
  <profile>
    <value>admin</value>
    <id>4</id>
    <description>admins users</description>
  </profile>
  <profile>
    <value>poweruser</value>  
    <id>5</id>
    <description>power users</description>
  </profile>
</user>

</root>

Can someone please supply an example for such a case?

EDIT: Added a complex profile entity

回答1:

The following should do what you're after:

/root/user[login='user1' and 
           name='User 1' and 
           profile='admin' and
           profile='operator']

Having two tests for the profile value might seem odd, but as there are multiple profile nodes then the condition will be satisfied as long as at least one node matches the test.

The reason you can compare profile directly to a string, even though it actually is a node is that the string-value of an element node is the string-value of all its descendants concatenated together, which in this case is just the contents of value.

If profile contained more elements than value you'd have to use a slightly more complex predicate test to determine the existence of a matching profile node based just on the value (this should work with your updated question):

/root/user[login='user1' and 
           name='User 1' and 
           profile[value='admin'] and
           profile[value='operator']]

回答2:

Here is a more exact answer (at present Greg Beech's answer does not check for condition 3. in the problem: the user element must have exactly 2 profile children):

/*/user
        [login='user1' 
        and            
         name='User 1' 
        and  
         not(profile[3])
        and          
         profile/value='admin' 
        and           
         profile/value='operator'
         ]

回答3:

Assuming users is the root:

/users/user[login='user1' and name='User 1' 
            and (profile='admin' and profile='operator')]

回答4:

/root/user[login='user1' and name='User 1' and profile/value='admin' and profile/value='operator'

来源：https://stackoverflow.com/questions/568713/xpath-expression-with-multiple-predicates

标签

xml

xpath

predicate