java操作xml的方法彙總及解析
阿新 • • 發佈：2020-01-07
這篇文章主要介紹了java操作xml的方法彙總及解析,文中通過示例程式碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值,需要的朋友可以參考下
一丶常用方法
主要有3個方面,1讀取xml檔案,2使用xpath根據指定路徑獲取某一節點資料 3,xml和java bean的轉換
XmlUtils.java
/**
* 和cn.hutool.core.util.XmlUtil許多功能重合,本類可以當做學習的例子
* 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();
}
// --------------------------------------
/**
* 讀取xml文件
* @param xmlInputStream
* @return
*/
public static Document readXml(InputStream xmlInputStream){
return readXml(xmlInputStream,false);
}
public static Document readXml(InputStream xmlInputStream,boolean validate){ // 參考mybatis parsing模組
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
}
// --------------------------------------
// 根據路徑獲取某一節點
public static XPath newXpath(){
return XPathFactory.newInstance().newXPath();
}
/**
* 根據路徑獲取某一節點,語法看 https://www.w3school.com.cn/xpath/xpath_syntax.asp
* @param expression
* @param root 可以是document,可以是Node等其他節點
* @param xpath
* @return 返回的節點可以修改
*/
public static Node evalNode(String expression,Object root,XPath xpath){
return (Node)evaluate(expression,root,XPathConstants.NODE,xpath);
}
public static NodeList evalNodeList(String expression,XPath xpath){
return (NodeList)evaluate(expression,XPathConstants.NODESET,xpath);
}
public static Double evalDouble(String expression,XPath xpath) {
return (Double) evaluate(expression,XPathConstants.NUMBER,xpath);
}
public static Boolean evalBoolean(String expression,XPath xpath) {
return (Boolean) evaluate(expression,XPathConstants.BOOLEAN,xpath);
}
public static String evalString(String expression,XPath xpath) {
return (String) evaluate(expression,XPathConstants.STRING,xpath);
}
public static Long evalLong(String expression,XPath xpath){
return Long.valueOf(evalString(expression,xpath));
}
public static Integer evalInteger(String expression,XPath xpath){
return Integer.valueOf(evalString(expression,xpath));
}
public static Float evalFloat(String expression,XPath xpath){
return Float.valueOf(evalString(expression,xpath));
}
public static Short evalShort(String expression,XPath xpath){
return Short.valueOf(evalString(expression,xpath));
}
private static Object evaluate(String expression,QName returnType,XPath xpath) {
try {
return xpath.evaluate(expression,returnType);
} catch (Exception e) {
throw new RuntimeException("Error evaluating XPath. Cause: " + e,e);
}
}
// --------------------------------------
// 轉成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 編碼
* @param isPretty 是否格式化輸出
* @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轉換
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);
}
}二丶測試
@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 選取此節點的所有子節點。
/ 從根節點選取。
// 從匹配選擇的當前節點選擇文件中的節點，而不考慮它們的位置。
. 選取當前節點。
.. 選取當前節點的父節點。
@ 選取屬性。
*/
@Test
public void evalNodeTest(){
BufferedInputStream bis=FileUtil.getInputStream("xml/bookstore.xml");
Document document=XmlUtils.readXml(bis);
XPath xpath=XmlUtils.newXpath();
// 1. 使用xpath表示式讀取根節點
Node rootNode=XmlUtils.evalNode("/bookstore",document,xpath);
Assert.assertEquals("bookstore",rootNode.getNodeName());
// 2. 使用xpath表示式讀取nodeList
NodeList bookNodeList =XmlUtils.evalNodeList("/bookstore/book",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表示式從節點讀取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表示式讀取屬性 陣列表示式從1開始,/@ 修飾獲取屬性
String lang=XmlUtils.evalString("/bookstore/book[1]/title/@lang",xpath);
Assert.assertEquals("en",lang);
lang=XmlUtils.evalString("/bookstore/book[2]/title/@lang",xpath);
Assert.assertEquals("cn",lang);
}
// --------------------------------- 轉換
@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"));
}以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支援我們。