Question

我有一个很大的xml：

<SomeRequest>
<Reservation>
...
</Reservation>
<Payment>
<cardNumber>....</cardNumber>
</Payment>
</SomeRequest>

现在我想从这个xml获得cardNumber值。它是String，我无法将其解析为xml Document因为它需要太多时间。所以，我有这个string，我就这样使用XPath：

String field = "/SomeRequest/Payment/cardNumber/text()";
XPathExpression compile = XPATH_FACTORY.newXPath().compile(field);
String value = compile.evaluate(new InputSource(new StringReader(request))); //request is xml string

但在执行此操作后，value为空。我尝试在xml Document（解析它）上执行它然后它工作。但现在我想用简单的String来做。我不想在这个字符串上使用正则表达式，因为它可以提供很多问题。如何使用XPath获取此cardNumber值？

Answer 1

你是正确的，有效的

public class XpathTest {
    private XPathFactory XPATH_FACTORY = new XPathFactoryImpl();

    private String request = "<SomeRequest>\n" +
            "<Reservation>\n" +
            "...\n" +
            "</Reservation>\n" +
            "<Payment>\n" +
            "<cardNumber>123</cardNumber>\n" +
            "</Payment>\n" +
            "</SomeRequest>";

    @Test
    public void name() throws Exception {
        String field = "/SomeRequest/Payment/cardNumber/text()";
        XPathExpression compile = XPATH_FACTORY.newXPath().compile(field);
        String value = compile.evaluate(new InputSource(new StringReader(request)));
        assertThat(value, equalTo("123"));
    }
}

Answer 2

您可以在toString上使用Document。

XPath从字符串xml返回空值

2 个答案: