如何使用单个jaxb实例生成xml

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import java.io.FileOutputStream;
import java.io.IOException;

public class JAXBExample {
    public static void main(String[] args) {
        try {
            // 创建Java对象模型
            Customer customer = new Customer();
            customer.setId(1);
            customer.setName("John Doe");
            customer.setAge(30);

            // 初始化JAXB上下文
            JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class);

            // 创建Marshaller
            Marshaller marshaller = jaxbContext.createMarshaller();

            // 设置Marshaller属性
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);

            // 创建输出流
            FileOutputStream outputStream = new FileOutputStream("customer.xml");

            // 调用Marshaller的marshal方法
            marshaller.marshal(customer, outputStream);

            // 关闭输出流
            outputStream.close();
        } catch (JAXBException | IOException e) {
            e.printStackTrace();
        }
    }
}