如何檢索屬性的值

Question

對於下面發佈的XML，我想獲得對應於lat = 53.0319947的id的值。

爲了達到這個目的我寫了下面的代碼。不幸的是我沒有得到任何結果。請讓我知道如何解決這個問題：

String expr0 = "//node[@lat=53.0319947]/id"; 
    xPath.compile(expr0); 
    String s = (String) xPath.evaluate(expr0, document, XPathConstants.STRING); 
    System.out.println(s); 

XML：

<?xml version='1.0' encoding='utf-8' ?> 
<osm> 
<node id="25779111" lat="53.0334062" lon="8.8461545"/> 
<node id="25779112" lat="53.0338904" lon="8.846314"/> 
<node id="25779119" lat="53.0337395" lon="8.8489255"/> 
<node id="25779121" lat="53.0338904" lon="8.85117"/>  
<node id="25779122" lat="53.0335748" lon="8.8511796"/> 
<node id="25779124" lat="53.0348595" lon="8.8514167"/> 
<node id="25779125" lat="53.0325729" lon="8.8511503"/> 
<node id="25779126" lat="53.0319947" lon="8.848581"/> 
<node id="25779130" lat="53.0331149" lon="8.8469982"/> 
<node id="25779131" lat="53.0302414" lon="8.8489081"/> 
<node id="25779132" lat="53.0302971" lon="8.8491894"/> 
<node id="25779168" lat="53.0314824" lon="8.8497289"/> 
<node id="25779170" lat="53.0328814" lon="8.8423081"/> 
<tag k="maxspeed" v="30"/> 
<tag k="maxspeed:zone" v="yes"/> 
</osm> 

Answer 1

爲ID是一個屬性也一樣，你應該使用@

String expr0 = "//node[@lat=53.0319947]/@id"; 

對於未來：

//node/something - You get all the something elements in a node element 
//node/@something - You get all the something node's attribute 
//node[@lat=53.0319947]/@id" you get all node's id attribute where lat attribute is 53.0319947