Java 如何通过属性值获取XML字符串
我试图解析一个XML文件,以获得一个“流程图”,步骤id是步骤的子元素:Java 如何通过属性值获取XML字符串,java,xml,parsing,Java,Xml,Parsing,我试图解析一个XML文件,以获得一个“流程图”,步骤id是步骤的子元素: <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <CATALOG> <FLOWCHART> <PRIMARYCODE>FC1</PRIMARYCODE> <NAME>Flowchart 1</NAME&g
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<CATALOG>
<FLOWCHART>
<PRIMARYCODE>FC1</PRIMARYCODE>
<NAME>Flowchart 1</NAME>
<STEPS>
<STEP id="1">was powered on.</STEP>
<STEP id="2">was not connected with a connection plate.</STEP>
</STEPS>
</FLOWCHART>
<FLOWCHART>
<PRIMARYCODE>FC2</PRIMARYCODE>
<NAME>Flowchart2</NAME>
<STEPS>
<STEP id="1">was not powered on.</STEP>
<STEP id="2">was connected with a connection plate.</STEP>
</STEPS>
</FLOWCHART>
</CATALOG>
FC1
流程图1
是通电的。
未与连接板连接。
FC2
流程图2
没有通电。
用连接板连接。
到目前为止,我所拥有的Java代码将打印所有步骤和流程图代码,以及流程图描述,但如何通过整数值请求特定步骤
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import java.io.File;
public class Flowchart
{
public static void main(String argv[])
{
try
{
//creating a constructor of file class and parsing an XML file
File file = new File("src/flowchart.xml");
//an instance of factory that gives a document builder
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
//an instance of builder to parse the specified xml file
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(file);
doc.getDocumentElement().normalize();
System.out.println("Root element: " + doc.getDocumentElement().getNodeName());
NodeList nodeList = doc.getElementsByTagName("FLOWCHART");
// nodeList is not iterable, so we are using for loop
for (int itr = 0; itr < nodeList.getLength(); itr++)
{
Node node = nodeList.item(itr);
System.out.println("\nNode Name: " + node.getNodeName());
if (node.getNodeType() == Node.ELEMENT_NODE)
{
Element eElement = (Element) node;
System.out.println("Flowchart ID: "+ eElement.getElementsByTagName("PRIMARYCODE").item(0).getTextContent());
for (int i = 0; i < (eElement.getElementsByTagName("STEPS").getLength() + 1) ; i++)
{
System.out.println("Steps: "+ eElement.getElementsByTagName("STEP").item(i).getTextContent());
}
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
import javax.xml.parsers.DocumentBuilderFactory;
导入javax.xml.parsers.DocumentBuilder;
导入org.w3c.dom.Document;
导入org.w3c.dom.NodeList;
导入org.w3c.dom.Node;
导入org.w3c.dom.Element;
导入java.io.File;
公共类流程图
{
公共静态void main(字符串argv[])
{
尝试
{
//创建file类的构造函数并解析XML文件
File File=新文件(“src/flopport.xml”);
//提供文档生成器的factory实例
DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
//用于分析指定xml文件的生成器实例
DocumentBuilder db=dbf.newDocumentBuilder();
文档doc=db.parse(文件);
doc.getDocumentElement().normalize();
System.out.println(“根元素:+doc.getDocumentElement().getNodeName());
NodeList NodeList=doc.getElementsByTagName(“流程图”);
//节点列表不可编辑,所以我们使用for循环
对于(int-itr=0;itr
为此,更方便的方法是使用XPath API:
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
public static String getStep(Document doc, String flowchartName, int stepId) throws XPathExpressionException {
XPathFactory xpf = XPathFactory.newInstance();
XPathExpression xpath = xpf.newXPath().compile("/CATALOG/FLOWCHART[NAME='"
+ flowchartName
+ "']/STEPS/STEP[@id='"
+ stepId
+ "']");
return xpath.evaluate(doc);
}