在上一篇文章中，我们学习了如何使用Java StAX Iterator API编写XML，这里我们将使用StAX光标API编写XML文件。

XMLStreamWriter

Java StAX Cursor API在创建XML和输出XML方面非常直接。
我们需要创建XMLStreamWriter对象并将数据写入其中。
有用的方法是writeStartDocument()，writeStartElement()，writeCharacters()，writeEndElement()和writeEndDocument()。

XMLStreamWriter示例

其中我们将创建一个HashMap，然后将其写入XML文件。

package com.theitroad.xml.stax;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.util.HashMap;
import java.util.Map;

import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;

public class StaxXMLStreamWriter {

  public static void main(String[] args) {
      String fileName = "/Users/hyman/tmp/employee.xml";
      String rootElement = "Employee";
      StaxXMLStreamWriter xmlStreamWriter = new StaxXMLStreamWriter();
      Map<String,String> elementsMap = new HashMap<String, String>();
      elementsMap.put("id", "1");
      elementsMap.put("name", "hyman");
      elementsMap.put("age", "29");
      elementsMap.put("role", "Java Developer");
      elementsMap.put("gender", "Male");
      xmlStreamWriter.writeXML(fileName, rootElement, elementsMap);
  }

  private void writeXML(String fileName, String rootElement, Map<String, String> elementsMap) {
      XMLOutputFactory xmlOutputFactory = XMLOutputFactory.newInstance();
      try{
          XMLStreamWriter xmlStreamWriter = xmlOutputFactory.createXMLStreamWriter(new FileOutputStream(fileName), "UTF-8");
          //start writing xml file
          xmlStreamWriter.writeStartDocument("UTF-8", "1.0");
          xmlStreamWriter.writeCharacters("\n");
          xmlStreamWriter.writeStartElement(rootElement);
          
          //write id as attribute
          xmlStreamWriter.writeAttribute("id", elementsMap.get("id"));
          
          //write other elements
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeStartElement("name");
          xmlStreamWriter.writeCharacters("\n\t\t"+elementsMap.get("name"));
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeEndElement();
          
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeStartElement("age");
          xmlStreamWriter.writeCharacters("\n\t\t"+elementsMap.get("age"));
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeEndElement();
          
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeStartElement("gender");
          xmlStreamWriter.writeCharacters("\n\t\t"+elementsMap.get("gender"));
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeEndElement();
          
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeStartElement("role");
          xmlStreamWriter.writeCharacters("\n\t\t"+elementsMap.get("role"));
          xmlStreamWriter.writeCharacters("\n\t");
          xmlStreamWriter.writeEndElement();
          //write end tag of Employee element
          xmlStreamWriter.writeCharacters("\n");
          xmlStreamWriter.writeEndElement();
          
          //write end document
          xmlStreamWriter.writeEndDocument();
          
          //flush data to file and close writer
          xmlStreamWriter.flush();
          xmlStreamWriter.close();
          
      }catch(XMLStreamException | FileNotFoundException e){
          e.printStackTrace();
      }
  }

}

当我们执行上面的XMLStreamWriter示例程序时，我们得到以下XML文件。

<?xml version="1.0" encoding="UTF-8"?>
<Employee id="1">
	<name>
		hyman
	</name>
	<age>
		29
	</age>
	<gender>
		Male
	</gender>
	<role>
		Java Developer
	</role>
</Employee>

请注意，为漂亮的打印XML使用了writeCharacters()，否则它将采用紧凑格式。