JAXB 默认属性值

JAXB（Java Architecture for XML Binding）是Java语言中用于将XML数据与Java对象进行绑定的技术。JAXB提供了一种简单的方式来处理XML数据，使得开发人员可以方便地读取和写入XML文件，而无需手动解析和生成XML。

java
import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class Person {
    private String name;
    private int age;
    private String gender = "unknown"; // 默认属性值
    @XmlElement
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    @XmlElement
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @XmlAttribute
    public String getGender() {
        return gender;
    }
    public void setGender(String gender) {
        this.gender = gender;
    }
}

java
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
public class Main {
    public static void main(String[] args) {
        try {
            JAXBContext context = JAXBContext.newInstance(Person.class);
            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
            Person person = new Person();
            person.setName("John");
            person.setAge(30);
            marshaller.marshal(person, System.out);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

xml
    John
    30