JAXB与XML

jaxb能够很好的读写xml，主要用于java对象和xml文件的互转，以下是一个java对象转成xml文件的例子

首先是bean文件，如下：

@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class TestBean implements Serializable {
	@XmlTransient
	private static final long serialVersionUID = 1L;
	private String name;
	private float price;
	private int age;
	private String add;
	/* list的表现形式
	 * <lists>
	 * 	<list></list>
	 * 	<list></list>
	 * </lists>
	 * */
	@XmlElementWrapper(name="DEGREES")
	@XmlElements({//表示或的关系，list中内容可以为以下两种类型
		@XmlElement(name="Degree",type=Degrees.class),
		@XmlElement(name="b",type=String.class)
	})
	private List<Degrees> degrees;
	@XmlJavaTypeAdapter(value=JaxbAdapter.class)
	private Date date;
	
	

	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public float getPrice() {
		return price;
	}
	public void setPrice(float price) {
		this.price = price;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getAdd() {
		return add;
	}
	public void setAdd(String add) {
		this.add = add;
	}
	public List<Degrees> getDegrees() {
		return degrees;
	}
	public void setDegrees(List<Degrees> degrees) {
		this.degrees = degrees;
	}
	
	public Date getDate() {
		return date;
	}
	public void setDate(Date date) {
		this.date = date;
	}
	@Override
	public String toString() {
		// TODO Auto-generated method stub
		StringBuilder str = new StringBuilder();
		str.append("[name: " + name);
		str.append("-- price: " + price);
		str.append("-- age: " + age);
		str.append("-- add: " + add + "]");
		return super.toString();
	}
	
}

写入xml文件中

public class JaxbWriteXml {
	public static void main(String args[]) throws JAXBException
	{
		JAXBContext context = JAXBContext.newInstance(TestBean.class);
		Marshaller marshaller = context.createMarshaller();
		marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
		TestBean bean = createBean();
//		TestBean2 bean2 = createBean2();
		marshaller.marshal(bean , new File("test.xml"));
	}

	private static TestBean2 createBean2() {
		// TODO Auto-generated method stub
		TestBean2 bean2 = new TestBean2();
		bean2.setId(02);
		bean2.setName("你好！");
		List<String> list = new ArrayList<String>();
		list.add("a");
		list.add("b");
		bean2.setList(list);
		return bean2;
	}

	private static TestBean createBean() {
		// TODO Auto-generated method stub
		TestBean bean  = new TestBean();
		bean.setName("张三丰");
		bean.setAge(23);
		bean.setPrice(new Float(29.7));
		bean.setAdd("wenzu road NO.6 nanjing china");
		bean.setDate(new Date());
		bean.setDegrees(getDegreess());
		return bean;
	}

	private static List<Degrees> getDegreess() {
		// TODO Auto-generated method stub
		List<Degrees> degrees = new ArrayList<Degrees>();
		Degrees degree = new Degrees();
		degree.setdID("1");
		degree.setdName("大学");
		degrees.add(degree);
		degree = new Degrees();
		degree.setdID("2");
		degree.setdName("高中");
		degrees.add(degree);
		degree = new Degrees();
		degree.setdID("3");
		degree.setdName("博士");
		degrees.add(degree);
		return degrees;
	}
}

对日期格式进行特殊的处理，需要继承xmladapter，从date类型转成string类型

public class JaxbAdapter extends XmlAdapter<String, Date> {
	@Override
	public Date unmarshal(String v) throws Exception {
		// TODO Auto-generated method stub
		return null;
	}

	@Override
	public String marshal(Date v) throws Exception {
		// TODO Auto-generated method stub
		SimpleDateFormat simple = new SimpleDateFormat("yyyy/MM/dd");
		return simple.format(v);
	}
}

生成如下xml文件：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<testBean>
    <name>张三丰</name>
    <price>29.7</price>
    <age>23</age>
    <add>wenzu road NO.6 nanjing china</add>
    <DEGREES>
        <Degree>
            <dID>1</dID>
            <dName>大学</dName>
        </Degree>
        <Degree>
            <dID>2</dID>
            <dName>高中</dName>
        </Degree>
        <Degree>
            <dID>3</dID>
            <dName>博士</dName>
        </Degree>
    </DEGREES>
    <date>2012/05/09</date>
</testBean>