DOM4j

[size=xx-small] [/size]DOM4J DOM4J:开源,支持XML,XPath,XSLT。与JDOM一样应用与JAVA平台。它的API完全支持DOM,SAX,JAXP。http://www.dom4j.org Dom4j是早期由开发JDOM的人分离出来独立开发的。与JDOM不同的是:Dom4j使用接口和抽象基类,虽然dom4j的API相对复杂一些,但比JDOM更灵活性。SUN的JAXM跟HIBERNATE都是使用DOM4J Dom4j也使用SAX解析器来分析XML文档,创建DOM4J树。此外,dom4j也接收DOM格式的内容,并提供从dom4j树到SAX事件流或W3C DOM树中的输出机制。 与JDOM不同的是:DOM4J自带了一个SAX解析器Aelfred2,如果没有显示设置,那么默认会加载JAXP配置的解析器,如果创建解析器失败,那么最后将使用dom4j自带的Aelfred2解析器。 DOM4J实例一:DOM4j的API使用 Dom4jTest.java Java代码 import java.io.IOException; import org.dom4j.Document; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.io.OutputFormat; import org.dom4j.io.XMLWriter; public class Dom4jTest { public static void main(String[] args) { //1.创建DOC对象 Document doc = DocumentHelper.createDocument(); //2.创建处理指令 doc.addProcessingInstruction("xml-stylesheet", "type='text/xsl' href='students.xsl'"); //3.创建根元素 Element root = DocumentHelper.createElement("students"); doc.setRootElement(root); //4.创建子元素 Element eltStu = root.addElement("student"); Element eltName = eltStu.addElement("name"); Element eltAge = eltStu.addElement("age"); //5.设置文本节点值 eltName.setText("张三"); eltAge.setText("23"); //6.输出 //PrintWriter pw = new PrintWriter(System.out); OutputFormat outFmt = new OutputFormat(" ",true); outFmt.setEncoding("gb2312"); try { //doc.write(pw); //pw.close(); XMLWriter xmlWriter = new XMLWriter(outFmt); xmlWriter.write(doc); } catch (IOException e) { e.printStackTrace(); } } } DOM4J实例二:遍历整个XML文档树 VisitorTest.java Java代码 import java.io.File; import org.dom4j.*; import org.dom4j.io.SAXReader; public class VisitorTest{ public static void main(String[] args){ SAXReader saxReader=new SAXReader(); try{ Document doc=saxReader.read(new File("students.xml")); doc.accept(new MyVisitor()); }catch (DocumentException e){ e.printStackTrace(); } } private static class MyVisitor extends VisitorSupport{ public void visit(Attribute node){ System.out.println("Attribute: "+node.getName()+"="+node.getValue()); } public void visit(Element node){ if(node.isTextOnly()){ System.out.println("Element: "+node.getName()+" "+node.getText()); }else{ System.out.println("------------"+node.getName()+"-------------"); } } public void visit(ProcessingInstruction node){ System.out.println("PI: "+node.getTarget()+" "+node.getText()); } } } DOM4J实例三:基于事件的处理(对内容多的XML进行处理) ElementHandlerTest.java Java代码 import java.io.File; import org.dom4j.*; import org.dom4j.io.SAXReader; public class ElementHandlerTest{ public static void main(String[] args){ SAXReader saxReader=new SAXReader(); saxReader.addHandler("/students/student",new StudentHandler()); try{ saxReader.read(new File("students.xml")); }catch (DocumentException e){ e.printStackTrace(); } } private static class StudentHandler implements ElementHandler{ public void onStart(ElementPath path){ Element elt=path.getCurrent(); System.out.println("Found student: "+elt.attributeValue("sn")); path.addHandler("name",new NameHandler()); } public void onEnd(ElementPath path){ path.removeHandler("name"); } } private static class NameHandler implements ElementHandler{ public void onStart(ElementPath path){ System.out.println(path.getPath()); } public void onEnd(ElementPath path){ Element elt=path.getCurrent(); System.out.println(elt.getName()+": "+elt.getText()); } } }