java中操作xml的方法总结
一丶常用方法
主要有3个方面, 1读取xml文件, 2使用xpath根据指定路径获取某一节点数据 3, xml和java bean的转换
XmlUtils.java
/**
* 和cn.hutool.core.util.XmlUtil许多功能重合, 本类可以当做学习的例子
* 可以直接使用cn.hutool.core.util.XmlUtil
*
* @author TimFruit
* @date 19-11-2 下午5:22
*/
public class XmlUtils {
// --------------------------------------
public static Document createXml(){
return XmlUtil.createXml();
}
// --------------------------------------
/**
* 读取xml文档
* @param xmlInputStream
* @return
*/
public static Document readXml(InputStream xmlInputStream){
return readXml(xmlInputStream, false);
}
public static Document readXml(InputStream xmlInputStream, boolean validate){ // 参考mybatis parsing模块
try {
DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();
factory.setValidating(validate);
factory.setNamespaceAware(false);
factory.setIgnoringComments(true);
factory.setIgnoringElementContentWhitespace(false);
factory.setCoalescing(false);
factory.setExpandEntityReferences(true);
DocumentBuilder builder=factory.newDocumentBuilder();
return builder.parse(xmlInputStream);
} catch (ParserConfigurationException e) {
throw new RuntimeException(e);
} catch (SAXException e) {
throw new RuntimeException(e);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public static Document readXml(String xmlStr){
return XmlUtil.parseXml(xmlStr); //使用hutool
}
// --------------------------------------
// 根据路径获取某一节点
public static XPath newXpath(){
return XPathFactory.newInstance().newXPath();
}
/**
* 根据路径获取某一节点, 语法看 https://www.w3school.com.cn/xpath/xpath_syntax.asp
* @param expression
* @param root 可以是document, 可以是Node等其他节点
* @param xpath
* @return 返回的节点可以修改
*/
public static Node evalNode(String expression, Object root, XPath xpath){
return (Node)evaluate(expression, root, XPathConstants.NODE, xpath);
}
public static NodeList evalNodeList(String expression, Object root, XPath xpath){
return (NodeList)evaluate(expression, root, XPathConstants.NODESET, xpath);
}
public static Double evalDouble(String expression, Object root, XPath xpath) {
return (Double) evaluate(expression, root, XPathConstants.NUMBER, xpath);
}
public static Boolean evalBoolean(String expression, Object root, XPath xpath) {
return (Boolean) evaluate(expression, root, XPathConstants.BOOLEAN, xpath);
}
public static String evalString(String expression, Object root, XPath xpath) {
return (String) evaluate(expression, root, XPathConstants.STRING, xpath);
}
public static Long evalLong(String expression, Object root, XPath xpath){
return Long.valueOf(evalString(expression, root, xpath));
}
public static Integer evalInteger(String expression, Object root, XPath xpath){
return Integer.valueOf(evalString(expression, root, xpath));
}
public static Float evalFloat(String expression, Object root, XPath xpath){
return Float.valueOf(evalString(expression, root, xpath));
}
public static Short evalShort(String expression, Object root, XPath xpath){
return Short.valueOf(evalString(expression, root, xpath));
}
private static Object evaluate(String expression, Object root, QName returnType, XPath xpath) {
try {
return xpath.evaluate(expression, root, returnType);
} catch (Exception e) {
throw new RuntimeException("Error evaluating XPath. Cause: " + e, e);
}
}
// --------------------------------------
// 转成string
public static String toStr(Node node){
return toStr(node, false);
}
public static String toStr(Node node, boolean isPretty){
return toStr(node, "utf-8", isPretty);
}
/**
*
* @param node
* @param charset 编码
* @param isPretty 是否格式化输出
* @return
*/
public static String toStr(Node node, String charset, boolean isPretty){
final StringWriter writer = StrUtil.getWriter();
final int INDENT_DEFAULT=2;
try {
XmlUtil.transform(new DOMSource(node), new StreamResult(writer), charset, isPretty ? INDENT_DEFAULT : 0);
} catch (Exception e) {
throw new UtilException(e, "Trans xml document to string error!");
}
return writer.toString();
}
//----------------------------------------
// 和java bean转换
public static JSONObject toJSONObject(String xmlStr){
return XML.toJSONObject(xmlStr);
}
public static JSONObject toJSONObject(Node node){
String xmlStr=toStr(node);
return toJSONObject(xmlStr);
}
public static <T> T toBean(Node node, Class<T> clazz){
return toJSONObject(node).toBean(clazz);
}
public static Node toNode(Object obj){
String xml=toXml(obj);
Node rootNode=readXml(xml).getFirstChild();
return rootNode;
}
public static String toXml(Object obj){
return XML.toXml(obj);
}
}
二丶测试
@Test
public void readXmlFromInputStreamTest(){
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
Document document=XmlUtils.readXml(bis);
String nodeName=document.getFirstChild().getNodeName();
System.out.println(nodeName);
Assert.assertTrue(nodeName.equals("bookstore"));
}
@Test
public void readXmlStringTest() throws IOException {
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
String xmlStr=StreamUtils.copyToString(bis, Charset.defaultCharset());
Document document=XmlUtils.readXml(xmlStr);
String nodeName=document.getFirstChild().getNodeName();
System.out.println(nodeName);
Assert.assertTrue(nodeName.equals("bookstore"));
}
// -------------------------------------------- xpath
/*
https://www.w3school.com.cn/xpath/xpath_syntax.asp
nodename 选取此节点的所有子节点。
/ 从根节点选取。
// 从匹配选择的当前节点选择文档中的节点，而不考虑它们的位置。
. 选取当前节点。
.. 选取当前节点的父节点。
@ 选取属性。
*/
@Test
public void evalNodeTest(){
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
Document document=XmlUtils.readXml(bis);
XPath xpath=XmlUtils.newXpath();
// 1. 使用xpath表达式读取根节点
Node rootNode=XmlUtils.evalNode("/bookstore", document, xpath);
Assert.assertEquals("bookstore", rootNode.getNodeName());
// 2. 使用xpath表达式读取nodeList
NodeList bookNodeList =XmlUtils.evalNodeList("/bookstore/book", document, xpath);
Node bookNode=null;
for(int i=0; i<bookNodeList.getLength(); i++){
bookNode=bookNodeList.item(i);
Assert.assertEquals("book", bookNode.getNodeName());
}
// 3. 使用xpath表达式从节点读取nodeList
bookNodeList=XmlUtils.evalNodeList("/book", rootNode, xpath);
for(int i=0; i<bookNodeList.getLength(); i++){
bookNode=bookNodeList.item(i);
Assert.assertEquals("book", bookNode.getNodeName());
}
// 4. 使用xpath表达式读取属性 数组表达式从1开始, /@ 修饰获取属性
String lang=XmlUtils.evalString("/bookstore/book[1]/title/@lang", document, xpath);
Assert.assertEquals("en", lang);
lang=XmlUtils.evalString("/bookstore/book[2]/title/@lang", document, xpath);
Assert.assertEquals("cn", lang);
}
// --------------------------------- 转换
@Test
public void xmlToJSONObjectTest() throws IOException {
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
String xmlStr=StreamUtils.copyToString(bis, Charset.forName("utf-8"));
JSONObject jso=XmlUtils.toJSONObject(xmlStr);
Assert.assertTrue(jso.getJSONObject("bookstore")!=null);
Assert.assertTrue(jso.getJSONObject("bookstore").getJSONArray("book")!=null);
}
@Test
public void nodeToJSONObjectTest(){
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
Document document=XmlUtils.readXml(bis);
JSONObject jso=XmlUtils.toJSONObject(document);
Assert.assertTrue(jso.getJSONObject("bookstore")!=null);
Assert.assertTrue(jso.getJSONObject("bookstore").getJSONArray("book")!=null);
}
@Test
public void toBeanTest(){
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
Document document=XmlUtils.readXml(bis);
XmlBookstoreDto dto=XmlUtils.toBean(document, XmlBookstoreDto.class);
Bookstore bookstore=dto.getBookstore();
Assert.assertNotNull(bookstore);
List<Book> bookList=bookstore.getBook();
Book book1=bookList.get(0);
Assert.assertTrue(book1.getTitle().getLang().equals("en"));
Assert.assertTrue(book1.getTitle().getContent().equals("Harry Potter"));
Assert.assertTrue(book1.getAuthor().equals("J K. Rowling"));
Book book2=bookList.get(1);
Assert.assertTrue(book2.getTitle().getLang().equals("cn"));
Assert.assertTrue(book2.getTitle().getContent().equals("where I am from"));
Assert.assertTrue(book2.getAuthor().equals("timfruit"));
}
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