如何获得具有不同属性的XML标签的价值？

Question

I need to get value from XML tag with different attributes.

For example: XML

<metaData>
    <parameter name="HTTP-Method">POST</parameter>
    <parameter name="HTTP-URI">/loan/test?testArg=1234&amp;id=5555555</parameter>
    <parameter name="HTTP-Version">HTTP/1.1</parameter>
    <parameter name="Host">localhost:7002</parameter>
    <parameter name="Content-Length">0</parameter>
    <parameter name="Origin">chrome-extension://fhbjgbiflinjbdggehcddcbncdddomop</parameter>
</netaData>

here I need to get a value of tag "parameter" with an attribute "HTTP-Method" and another one with attribute "HTTP-URI"

This what I do:

NodeList nodeList = document.getElementsByTagName("parameter");
for (int i = 0, size = nodeList.getLength(); i < size; i++) {
        Element elem = (Element) nodeList.item(i);

Here I got all the parameter tags. How can I get the specific one?

Answer 1

This block of code

for (int i = 0; i < nodeList.getLength(); i++) {
    Element elem = (Element) nodeList.item(i);
    String attribute = elem.getAttribute("name");
    if ("HTTP-Method".equals(attribute) || "HTTP-URI".equals(attribute)) {
        System.out.println(elem.getTextContent());
    }
}

will print

POST
/loan/test?testArg=1234&id=5555555

Answer 2

With the library Dynamics & Java 8 this can be done pretty directly. Using Streams and lambdas we can walk through the xml in a fairly natural way.

XmlDynamic example = new XmlDynamic("<metaData>" +
    "<parameter name=\"HTTP-Method\">POST</parameter>" +
    "<parameter name=\"HTTP-URI\">/loan/test?testArg=1234&amp;id=5555555</parameter>" +
"</metaData>");

String uri = example.get("metaData")
    .children()
    .filter(parameter -> parameter.get("@name").asString().equals("HTTP-URI"))
    .findAny()
    .map(parameter -> parameter.asString())
    .get(); // assuming this value is always there

Or perhaps to be a little more defensive, if the xml is less guaranteed to have what we expect.

Optional<String> uri = example.get("metaData")
    .children()
    .filter(param -> param.get("@name").maybe().asString().orElse("").equals("HTTP-URI"))
    .findAny()
    .map(param -> param.asString());

You can add the library to your maven project with

<dependency>
  <groupId>com.github.alexheretic</groupId>
  <artifactId>dynamics</artifactId>
  <version>2.3</version>
</dependency>

Answer 3

You can use the Scilca XML Progression Package available at GitHub.

List<Node> list = document.getElementsWithAttribute(new Attribute("Name", "HTTP-URI", true); // True cause the value of the attribute should be same

Node need = list.get(0);