java - 选择性编码对象

Question

我需要执行选择性编码对象。例如:

有一个类联系方式:

@XmlRootElement(name = "contact")
public class Contact {

    private String name;
    private String number;
    private String address;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

}

编码对象:

public static void main(String[] args) throws JAXBException {    
        Contact contact = new Contact();
        contact.setAddress("5 Av.");
        contact.setName("John");
        contact.setNumber("5555555");    

        JAXBContext context = JAXBContext.newInstance(Contact.class);
        Marshaller marshaller = context.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, Boolean.TRUE);
        marshaller.marshal(contact, System.out);
    }

结果我们有:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<contact>
    <address>5 street</address>
    <name>John</name>
    <number>5555555</number>
</contact>

有没有简单的方法来执行选择性编码？例如，仅获取输出的地址:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<contact>
    <address>5 street</address>
</contact>

谢谢!

Answer 1

未指定时，默认为类上有以下注释:

@XmlAccessorType(XmlAccessType.PUBLIC_MEMBER)

这意味着 JAXB 将使用所有公共(public)成员，即所有 getter 方法。

您可以保留默认值并禁止您不需要的 getter 方法，也可以更改默认值并显式标记您确实想要处理的 getter 方法。

要抑制 getter 方法，请使用 @XmlTransient 进行注释:

Prevents the mapping of a JavaBean property/type to XML representation.

要更改默认值，请使用 @XmlAccessorType(XmlAccessType.NONE) 进行注释:

None of the fields or properties is bound to XML unless they are specifically annotated with some of the JAXB annotations.

然后使用 @XmlElement 显式注释所需的 getter 方法:

Maps a JavaBean property to a XML element derived from property name.

使用@XmlTransient

@XmlRootElement(name = "contact")
class Contact {

    private String name;
    private String number;
    private String address;

    @XmlTransient
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @XmlTransient
    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

}

使用@XmlAccessorType(XmlAccessType.NONE)

@XmlRootElement(name = "contact")
@XmlAccessorType(XmlAccessType.NONE)
class Contact {

    private String name;
    private String number;
    private String address;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    @XmlElement
    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

}

输出(来自两者)

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<contact>
    <address>5 Av.</address>
</contact>