JAVA：从XML文档中提取元素

Question

I'm using javax.xml.parsers to navigate through an XML document like the one below:

`

<ContextElement>
    <DimensionNode>Role</DimensionNode>
    <Value>Administration</Value>
    <TailoringExpressions>
        <TailoringExpression>
            <Relation>Student</Relation>
            <ProjAtt>
                <Attribute>Matr</Attribute>
                <Attribute>SName</Attribute>
                <Attribute>SSurname</Attribute>
                <Attribute>SDateOfBirth</Attribute>
                <Attribute>SEmail</Attribute>
                <Attribute>SAddress</Attribute>
            </ProjAtt>
            <Condition/>
            <SemiJoinRel/>
            <SemiJoinOn/>
            <SemiJoinCond/>
        </TailoringExpression>
    </TailoringExpressions>
</ContextElement>
<ContextElement>
    <DimensionNode>Deadline</DimensionNode>
    <Value>Lost</Value>
    <TailoringExpressions>
        <TailoringExpression>
            <Relation>Deadline</Relation>
            <ProjAtt>
                <Attribute>IdDeadline</Attribute>
                <Attribute>Student</Attribute>                  
                <Attribute>DeadlineDate</Attribute>
                <Attribute>Description</Attribute>
                <Attribute>IsMet</Attribute>
            </ProjAtt>
            <Condition>DeadlineDate LT CurrentDate AND IsMet=False</Condition>
            <SemiJoinRel/>
            <SemiJoinOn/>
            <SemiJoinCond/>
        </TailoringExpression>
    </TailoringExpressions>
</ContextElement>

`

I've a problem because I need to extract the object/node ContextElement which has as DimensionNode the value "Role" and as Value the value "Administration" and I'm not able to write a working code! Can someone tell me how to do that? Thanks

Answer 1

I think the best way to extract values is to use xpath:

XPath xpath = XPathFactory.newInstance().newXPath();
String expression = "/widgets/widget";
InputSource inputSource = new InputSource("widgets.xml");
NodeSet nodes = (NodeSet) xpath.evaluate(expression, inputSource, XPathConstants.NODESET);

For more information look at oracle documentation .