如何使用“文档”构建器工厂获取xml属性值

How to get attribute values by using the following code i am getting ; as output for msg . I want to print MSID,type,CHID,SPOS,type,PPOS values can any one solve this issue .

如何通过使用以下代码获取属性值;作为msg的输出。我想打印MSID，类型，CHID，SPOS，类型，PPOS值可以解决这个问题。

String xml1="<message MSID='20' type='2635'>"
        +"<che CHID='501' SPOS='2'>"
        +"<pds type='S'>"
        +"<position PPOS='S01'/>"
        +"</pds>"
        +"</che>"
        +"</message>";

InputSource source = new InputSource(new StringReader(xml1));

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document document = db.parse(source);

XPathFactory xpathFactory = XPathFactory.newInstance();
XPath xpath = xpathFactory.newXPath();

String msg = xpath.evaluate("/message/che/CHID", document);
String status = xpath.evaluate("/pds/position/PPOS", document);

System.out.println("msg=" + msg + ";" + "status=" + status);

2 个解决方案

#1

You need to use @ in your XPath for an attribute, and also your path specifier for the second element is wrong:

您需要在XPath中使用@作为属性，并且第二个元素的路径说明符也是错误的：

String msg = xpath.evaluate("/message/che/@CHID", document);
String status = xpath.evaluate("/message/che/pds/position/@PPOS", document);

With those changes, I get an output of:

通过这些更改，我得到了一个输出：

msg=501;status=S01

#2

You can use Document.getDocumentElement() to get the root element and Element.getElementsByTagName() to get child elements:

您可以使用Document.getDocumentElement（）来获取根元素，使用Element.getElementsByTagName（）来获取子元素：

Document document = db.parse(source);

Element docEl = document.getDocumentElement(); // This is <message>

String msid = docEl.getAttribute("MSID");
String type = docEl.getAttribute("type");

Element position = (Element) docEl.getElementsByTagName("position").item(0);
String ppos = position.getAttribute("PPOS");

System.out.println(msid); // Prints "20"
System.out.println(type); // Prints "2635"
System.out.println(ppos); // Prints "S01"

#1