Java如何在JAXB中定义XML元素顺序？

在此代码段中，您将学习如何定义JAXB API生成的XML元素的顺序。要定义元素顺序，我们需要@XmlType在POJO中使用注释。在此注释propOrder中，我们定义了哪个元素应该首先出现，哪个元素应该放在最后。

由生成的XMLmarshaller下面将具有以下顺序：street，city，province，zipCode和country作为最后的XML元素。

package org.nhooo.example.jaxb;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

@XmlRootElement(name = "customerAddress")
@XmlType(propOrder = {"street", "city", "province", "zipCode", "country"})
public class Address {
    private String street;
    private String city;
    private String province;
    private String country;
    private String zipCode;

    @XmlElement
    public String getStreet() {
        return street;
    }

    public void setStreet(String street) {
        this.street = street;
    }

    @XmlElement
    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    @XmlElement
    public String getProvince() {
        return province;
    }

    public void setProvince(String province) {
        this.province = province;
    }

    @XmlElement
    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    @XmlElement(name = "postCode")
    public String getZipCode() {
        return zipCode;
    }

    public void setZipCode(String zipCode) {
        this.zipCode = zipCode;
    }

    @Override
    public String toString() {
        return "Address{" +
                "street='" + street + ''' +
                ", city='" + city + ''' +
                ", province='" + province + ''' +
                ", country='" + country + ''' +
                ", zipCode='" + zipCode + ''' +
                '}';
    }
}

现在，让我们创建一个程序来运行AddressPOJO的编组过程，以将其转换为XML文档：

package org.nhooo.example.jaxb;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class JAXBElementOrder {
    public static void main(String[] args) {
        Address address = new Address();
        address.setStreet("Sunset Road");
        address.setCity("Denpasar");
        address.setProvince("Bali");
        address.setCountry("Indonesia");
        address.setZipCode("800000");

        try {
            JAXBContext context = JAXBContext.newInstance(Address.class);

            Marshaller marshaller = context.createMarshaller();
            marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
            marshaller.marshal(address, System.out);
        } catch (JAXBException e) {
            e.printStackTrace();
        }
    }
}

它将为您提供以下输出：

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<customerAddress>
    <street>Sunset Road</street>
    <city>Denpasar</city>
    <province>Bali</province>
    <country>Indonesia</country>
    <postCode>800000</postCode>
</customerAddress>