※xml.xml
<?xml version="1.0" encoding="UTF-8"?> <root>top1 top2 <first fa="f1" fb="1f"> first-1 <second1 sa="s1">aaa</second1> <second2>bbb</second2> <second3>ccc</second3> </first> top3 <first fa="f2" fb="2f"> first-2 <second1 sa="s2">ddd</second1> <second2>eee</second2> <second3>fff</second3> </first> top4 <first fa="f3" fb="3f"> first-3 <second1 sa="s3">ggg</second1> <second2>hhh</second2> <second3>iii</second3> </first> </root>
※
※讀取元素
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class Test {
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("src/main/java/xml.xml");
NodeList nl = doc.getElementsByTagName("root");
for (int i = 0; i < nl.getLength(); i++) {
Node rootNode = nl.item(i);
// System.out.println(rootNode.getNodeName());
// System.out.println(rootNode.getNodeType());
// System.out.println(rootNode.getNodeValue());
// System.out.println(rootNode.getTextContent());
Node fChildNode = rootNode.getFirstChild();
// System.out.println(fChildNode.getNodeName());
// System.out.println(fChildNode.getNodeType());
// System.out.println(fChildNode.getNodeValue());
// System.out.println(fChildNode.getTextContent());
NodeList nodeList = rootNode.getChildNodes();
for (int j = 0; j < nodeList.getLength(); j++) {
Node nn = nodeList.item(j);
System.out.println(nn.getNodeName());
System.out.println(nn.getNodeType());
System.out.println(nn.getNodeValue());
System.out.println("------------------");
}
}
}
}
※如果XML不是讀檔，而是傳來一個String，裡面是XML，可以用
InputStream in = new ByteArrayInputStream(xmlString.getBytes("UTF-8"));
再把in放在builder.parse裡即可
※Node.getNodeType()會回傳一個數字，API 寫的不清楚，要看Node.class的介面原碼才知道，
1是元素、2屬性、3文字，一般就用這三個
※要注意元素和元素之間的空，也算節點
※讀取屬性
import java.io.IOException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
public class Test {
public static void main(String[] args) throws ParserConfigurationException, SAXException, IOException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse("src/main/java/xml.xml");
NodeList nl = doc.getElementsByTagName("root");
for (int i = 0; i < nl.getLength(); i++) {
Node rootNode = nl.item(i);
NodeList nodeList = rootNode.getChildNodes();
for (int j = 0; j < nodeList.getLength(); j++) {
Node nn = nodeList.item(j);
if (Node.ELEMENT_NODE == nn.getNodeType()) {
System.out.println(nn.getNodeName());
NamedNodeMap attrs = nn.getAttributes();
for (int k = 0; k < attrs.getLength(); k++) {
Node attr = attrs.item(k);
System.out.println(attr.getNodeName());
System.out.println(attr.getNodeValue());
System.out.println("------------------");
}
System.out.println("===================");
}
}
}
}
}
※nodeList回傳7，因為元素和元素之間也算節點，所以用Node.ELEMENT_NODE過濾掉
三個first算3個節點，還有first和first之間又有2個節點，最後first和root之間也有兩個節點，所以是7
最後的first和root雖然我沒寫文字，但還是節點
※讀到的text節點是有tab和換行的，不想要可以trim()掉
※寫檔
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
public class Test {
public static void main(String[] args)
throws ParserConfigurationException, SAXException, IOException, TransformerException {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.newDocument();
// 新增元素
Element root = doc.createElement("root");
Element first = doc.createElement("first");
Element second1 = doc.createElement("second1");
Element second2 = doc.createElement("second2");
Element second3 = doc.createElement("second3");
// 元素的text
root.appendChild(doc.createTextNode("top1" + System.getProperty("line.separator") + "\ttop2"));
first.appendChild(doc.createTextNode("\tfirst-1"));
second1.appendChild(doc.createTextNode("aaa"));
second2.appendChild(doc.createTextNode("bbb"));
second3.appendChild(doc.createTextNode("ccc"));
// 元素組合
root.appendChild(first);
first.appendChild(second1);
first.appendChild(second2);
first.appendChild(second3);
// 元素屬性
first.setAttribute("fa", "f1");
first.setAttribute("fb", "1f");
second1.setAttribute("sa", "s1");
doc.appendChild(root);
DOMSource source = new DOMSource(doc);
// 生成output
File file = new File("D:/" + File.separator + "xml.xml");
OutputStream out = new FileOutputStream(file, true);
StreamResult result = new StreamResult(out);
// 生成檔案
TransformerFactory tFactory = TransformerFactory.newInstance();
Transformer tf = tFactory.newTransformer();
tf.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
tf.transform(source, result);
out.close();
System.out.println("XML已生成");
}
}
※生出來的XML是不會排版的
※此例只是寫其中一個first而已
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