1、解析XML主要有四种方式
1.DOM方式解析XML（与平台无关,JAVA提供,一次性加载XML文件内容,形成树结构,不适用于大文件）
2.SAX方式解析XML（基于事件驱动,逐条解析,适用于只处理XML数据,不易编码）
3.JDOM方式解析XML（使用具体类而不使用接口）
4.DOM4j方式解析XML（推荐）
2、代码实现
（1）XML文件
1 <?xml version="1.0" encoding="UTF-8"?> 2 <bookstore> 3 <book id="1"> 4 <name>平凡的世界</name> 5 <author>路遥</author> 6 <year>2017</year> 7 <price>77</price> 8 </book> 9 <book id="2"> 10 <name>百年孤独</name> 11 <author>加西亚·马尔克斯</author> 12 <year>1967</year> 13 <price>80</price> 14 </book> 15 <book id="3"> 16 <name>程序员的修炼之道</name> 17 <author>安德鲁·亨特、大卫·托马斯</author> 18 <year>2011</year> 19 <price>156</price> 20 </book> 21 </bookstore>
（2）XML对应的Bean类
1 public class Book { 2 3 private int id; 4 private String name; 5 private String author; 6 private int year; 7 private double price; 8 9 /** 10 * @return the id 11 */ 12 public int getId() { 13 return id; 14 } 15 /** 16 * @param id the id to set 17 */ 18 public void setId(int id) { 19 this.id = id; 20 } 21 /** 22 * @return the name 23 */ 24 public String getName() { 25 return name; 26 } 27 /** 28 * @param name the name to set 29 */ 30 public void setName(String name) { 31 this.name = name; 32 } 33 /** 34 * @return the author 35 */ 36 public String getAuthor() { 37 return author; 38 } 39 /** 40 * @param author the author to set 41 */ 42 public void setAuthor(String author) { 43 this.author = author; 44 } 45 /** 46 * @return the year 47 */ 48 public int getYear() { 49 return year; 50 } 51 /** 52 * @param year the year to set 53 */ 54 public void setYear(int year) { 55 this.year = year; 56 } 57 /** 58 * @return the price 59 */ 60 public double getPrice() { 61 return price; 62 } 63 /** 64 * @param price the price to set 65 */ 66 public void setPrice(double price) { 67 this.price = price; 68 } 69 70 @Override 71 public String toString() { 72 return "Book [id=" + id + ", name=" + name + ", author=" + author + ", year=" + year + ", price=" + price + "]"; 73 } 74 75 }
3、XML解析
（1）DOM方式解析XML
1 public class ReadxmlByDom { 2 private static DocumentBuilderFactory dbFactory = ; 3 private static DocumentBuilder db = ; 4 private static Document document = ; 5 private static List<Book> books = ; 6 static{ 7 try { 8 dbFactory = DocumentBuilderFactory.newInstance(); 9 db = dbFactory.newDocumentBuilder(); 10 } catch (ParserConfigurationException e) { 11 e.printStackTrace(); 12 } 13 } 14 15 public static List<Book> getBooks(String fileName) throws Exception{ 16 //将给定 URI 的内容解析为一个 XML 文档,并返回Document对象 17 document = db.parse(fileName); 18 //按文档顺序返回包含在文档中且具有给定标记名称的所有 Element 的 NodeList 19 NodeList bookList = document.getElementsByTagName("book"); 20 books = new ArrayList<Book>(); 21 //遍历books 22 for(int i=0;i<bookList.getLength();i++){ 23 Book book = new Book(); 24 //获取第i个book结点 25 org.w3c.dom.Node node = bookList.item(i); 26 //获取第i个book的所有属性 27 NamedNodeMap namedNodeMap = node.getAttributes(); 28 //获取已知名为id的属性值 29 String id = namedNodeMap.getNamedItem("id").getTextContent();//System.out.println(id); 30 book.setId(Integer.parseInt(id)); 31 32 //获取book结点的子节点,包含了Test类型的换行 33 NodeList cList = node.getChildNodes();//System.out.println(cList.getLength());9 34 35 //将一个book里面的属性加入数组 36 ArrayList<String> contents = new ArrayList<>(); 37 for(int j=1;j<cList.getLength();j+=2){ 38 39 org.w3c.dom.Node cNode = cList.item(j); 40 String content = cNode.getFirstChild().getTextContent(); 41 contents.add(content); 42 //System.out.println(contents); 43 } 44 45 book.setName(contents.get(0)); 46 book.setAuthor(contents.get(1)); 47 book.setYear(Integer.parseInt(contents.get(2))); 48 book.setPrice(Double.parseDouble(contents.get(3))); 49 books.add(book); 50 } 51 52 return books; 53 54 } 55 56 public static void main(String args[]){ 57 String fileName = "src/res/books.xml"; 58 try { 59 List<Book> list = ReadxmlByDom.getBooks(fileName); 60 for(Book book :list){ 61 System.out.println(book); 62 } 63 } catch (Exception e) { 64 // TODO Auto-generated catch block 65 e.printStackTrace(); 66 } 67 } 68 69 }
（2）SAX方式解析XML（比较麻烦，需要配置一个handler处理器）
DefaultHandler处理器
1 /** 2 * 用SAX解析xml文件时需要的handler 3 */ 4 public class SAXParseHandler extends DefaultHandler { 5 private List<Book> list; //存放解析到的book数组 6 private Book book; //存放当前解析的book 7 8 private String content = ; //存放当前节点值 9 10 /** 11 * 开始解析xml文档时调用此方法 12 */ 13 @Override 14 public void startDocument() throws SAXException { 15 16 super.startDocument(); 17 System.out.println("开始解析xml文件"); 18 list = new ArrayList<Book>(); 19 } 20 21 22 23 /** 24 * 文档解析完成后调用此方法 25 */ 26 @Override 27 public void endDocument() throws SAXException { 28 29 super.endDocument(); 30 System.out.println("xml文件解析完毕"); 31 } 32 33 34 35 /** 36 * 开始解析节点时调用此方法 37 */ 38 @Override 39 public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { 40 41 super.startElement(uri, localName, qName, attributes); 42 43 //当节点名为book时,获取book的属性id 44 if(qName.equals("book")){ 45 book = new Book(); 46 String id = attributes.getValue("id");//System.out.println("id值为"+id); 47 book.setId(Integer.parseInt(id)); 48 } 49 50 } 51 52 53 /** 54 *节点解析完毕时调用此方法 55 * 56 *@param qName 节点名 57 */ 58 @Override 59 public void endElement(String uri, String localName, String qName) throws SAXException { 60 61 super.endElement(uri, localName, qName); 62 if(qName.equals("name")){ 63 book.setName(content); 64 //System.out.println("书名"+content); 65 }else if(qName.equals("author")){ 66 book.setAuthor(content); 67 // System.out.println("作者"+content); 68 }else if(qName.equals("year")){ 69 book.setYear(Integer.parseInt(content)); 70 // System.out.println("年份"+content); 71 }else if(qName.equals("price")){ 72 book.setPrice(Double.parseDouble(content)); 73 // System.out.println("价格"+content); 74 }else if(qName.equals("book")){ //当结束当前book解析时,将该book添加到数组后置为空，方便下一次book赋值 75 list.add(book); 76 book = ; 77 } 78 79 } 80 81 82 83 /** 84 * 此方法用来获取节点的值 85 */ 86 @Override 87 public void characters(char[] ch, int start, int length) throws SAXException { 88 89 super.characters(ch, start, length); 90 91 content = new String(ch, start, length); 92 //收集不为空白的节点值 93 // if(!content.trim().equals("")){ 94 // System.out.println("节点值为："+content); 95 // } 96 97 } 98 99 public List<Book> getBooks(){ 100 return list; 101 } 102 103 }
用SAX方式读取xml文件
1 /** 2 * 用SAX方式读取xml文件 3 */ 4 public class ReadXmlBySAX { 5 6 private static List<Book> books = ; 7 8 private SAXParserFactory sParserFactory = ; 9 private SAXParser parser = ; 10 11 12 public List<Book> getBooks(String fileName) throws Exception{ 13 SAXParserFactory sParserFactory = SAXParserFactory.newInstance(); 14 SAXParser parser = sParserFactory.newSAXParser(); 15 16 SAXParseHandler handler = new SAXParseHandler(); 17 parser.parse(fileName, handler); 18 19 return handler.getBooks(); 20 21 } 22 /** 23 * @param args 24 */ 25 public static void main(String[] args) { 26 try { 27 books = new ReadXmlBySAX().getBooks("src/res/books.xml"); 28 for(Book book:books){ 29 System.out.println(book); 30 } 31 32 } catch (Exception e) { 33 e.printStackTrace(); 34 } 35 36 } 37 38 }
（3）JDOM方式解析XML
1 /** 2 * 用JDOM方式读取xml文件 3 */ 4 public class ReadXMLByJDom { 5 6 private List<Book> books = ; 7 private Book book = ; 8 9 public List<Book> getBooks(String fileName){ 10 SAXBuilder saxBuilder = new SAXBuilder(); 11 try { 12 Document document = saxBuilder.build(new FileInputStream(fileName)); 13 //获取根节点bookstore 14 Element rootElement = document.getRootElement(); 15 //获取根节点的子节点，返回子节点的数组 16 List<Element> bookList = rootElement.getChildren(); 17 books = new ArrayList<Book>(); 18 for(Element bookElement : bookList){ 19 book = new Book(); 20 //获取bookElement的属性 21 List<Attribute> bookAttributes = bookElement.getAttributes(); 22 for(Attribute attribute : bookAttributes){ 23 if(attribute.getName().equals("id")){ 24 String id = attribute.getValue(); //System.out.println(id); 25 book.setId(Integer.parseInt(id)); 26 } 27 } 28 //获取bookElement的子节点 29 List<Element> children = bookElement.getChildren(); 30 for(Element child : children){ 31 if(child.getName().equals("name")){ 32 String name = child.getValue();//System.out.println(name); 33 book.setName(name); 34 }else if(child.getName().equals("author")){ 35 String author = child.getValue(); 36 book.setAuthor(author);//System.out.println(author); 37 }else if(child.getName().equals("year")){ 38 String year = child.getValue(); 39 book.setYear(Integer.parseInt(year)); 40 }else if(child.getName().equals("price")){ 41 String price = child.getValue(); 42 book.setPrice(Double.parseDouble(price)); 43 } 44 45 } 46 47 books.add(book); 48 book = ; 49 50 } 51 52 } catch (FileNotFoundException e) { 53 54 e.printStackTrace(); 55 } catch (JDOMException e) { 56 57 e.printStackTrace(); 58 } catch (IOException e) { 59 60 e.printStackTrace(); 61 } 62 63 return books; 64 65 } 66 67 68 public static void main(String[] args) { 69 // TODO Auto-generated method stub 70 String fileName = "src/res/books.xml"; 71 List<Book> books= new ReadXMLByJDom().getBooks(fileName); 72 for(Book book : books){ 73 System.out.println(book); 74 } 75 } 76 77 }
4、DOM4j方式解析XML
1 /** 2 * 用DOM4J方法读取xml文件 3 */ 4 public class ReadXMLByDom4j { 5 6 private List<Book> bookList = ; 7 private Book book = ; 8 9 public List<Book> getBooks(File file){ 10 11 SAXReader reader = new SAXReader(); 12 try { 13 Document document = reader.read(file); 14 Element bookstore = document.getRootElement(); 15 Iterator storeit = bookstore.elementIterator(); 16 17 bookList = new ArrayList<Book>(); 18 while(storeit.hasNext()){ 19 20 book = new Book(); 21 Element bookElement = (Element) storeit.next(); 22 //遍历bookElement的属性 23 List<Attribute> attributes = bookElement.attributes(); 24 for(Attribute attribute : attributes){ 25 if(attribute.getName().equals("id")){ 26 String id = attribute.getValue();//System.out.println(id); 27 book.setId(Integer.parseInt(id)); 28 } 29 } 30 31 Iterator bookit = bookElement.elementIterator(); 32 while(bookit.hasNext()){ 33 Element child = (Element) bookit.next(); 34 String nodeName = child.getName(); 35 if(nodeName.equals("name")){ 36 //System.out.println(child.getStringValue()); 37 String name = child.getStringValue(); 38 book.setName(name); 39 }else if(nodeName.equals("author")){ 40 String author = child.getStringValue(); 41 book.setAuthor(author); 42 }else if(nodeName.equals("year")){ 43 String year = child.getStringValue(); 44 book.setYear(Integer.parseInt(year)); 45 }else if(nodeName.equals("price")){ 46 String price = child.getStringValue(); 47 book.setPrice(Double.parseDouble(price)); 48 } 49 } 50 bookList.add(book); 51 book = ; 52 53 } 54 } catch (DocumentException e) { 55 56 e.printStackTrace(); 57 } 58 59 60 return bookList; 61 62 } 63 64 65 /** 66 * @param args 67 */ 68 public static void main(String[] args) { 69 // TODO Auto-generated method stub 70 File file = new File("src/res/books.xml"); 71 List<Book> bookList = new ReadXMLByDom4j().getBooks(file); 72 for(Book book : bookList){ 73 System.out.println(book); 74 } 75 } 76 77 }