Java 如何检索/提取XML元素属性值

我有一个如下所示的XML

<?xml version="1.0" encoding="utf-8"?>
    <PaymentElement>
        <Payment seqID="3">
            <TPayment>
                <Status>status</Status>
            </TPayment>
        </Payment>
    </PaymentElement>

地位

问题是如何通过java检索/提取seqID值，该值是其中的3

我试过下面的方法，但不起作用

InputStream xml = conn.getInputStream(); 
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(xml);
NodeList list = doc.getElementsByTagName("PaymentElement");

for(int i=0; i<=list.getLength();i++){
    NodeList paySeq=doc.getElementsByTagName("Payment seqID");
System.out.println("Payment seqID"+paySeq);
}

InputStream xml=conn.getInputStream（）；
DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance（）；
DocumentBuilder db=dbf.newDocumentBuilder（）；
Document doc=db.parse（xml）；
NodeList list=doc.getElementsByTagName（“PaymentElement”）；
对于（int i=0；i
result
现在应该有
3

完整示例

import java.io.*;
import javax.xml.xpath.*;
import org.xml.sax.InputSource;

public class Demo {

    public static void main(String[] args) throws Exception {
        InputStream inputStream = new FileInputStream("sample.xml");
        InputSource inputSource = new InputSource(inputStream);
        XPath xpath = XPathFactory.newInstance().newXPath();
        XPathExpression expr = xpath.compile("/PaymentElement/Payment/@seqID");
        Object result = expr.evaluate(inputSource, XPathConstants.STRING);
        System.out.println(result);
    }

}

试一试

输出

 Payment seqID = 3

结果为空值3未出现公共静态void main（字符串[]args）引发异常{InputStream xml=new FileInputStream（“sample.xml”）；DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance（）；DocumentBuilder db=dbf.newDocumentBuilder（）；Document doc=db.parse（xml）；XPath XPath=XPathFactory.newInstance（）.newXPath（）；XPathExpression expr=XPath.compile（“/PaymentElement/Payment/@seqID”）；对象结果=expr.evaluate（doc，XPathConstants.STRING）；系统.out.println（result）；}@RKajaMohideen-+1，我还在您的答案中添加了您的评论的修改版本。我所做的更改是取消对DOM的转换。@BlaiseDoughan，这很好。我只是为他试图解决的问题提供了解决方案。我没有集中精力在DOM部分：-）我在答案中复制粘贴了完整版本，请重试
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();
    Document doc = db.parse(new File("1.xml"));
    Element e  = (Element)doc.getDocumentElement().getElementsByTagName("Payment").item(0);
    String id = e.getAttribute("seqID");
    System.out.println("Payment seqID = " + id);

 Payment seqID = 3