我是 java XML 绑定(bind)的新手。

这是我的类(class)

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

/**
 * @author Martin Burchard
 * 
 */
@XmlRootElement(name = "user")
    public class User {
    private String id;
    private String nickname;
    private String email;
    private String password;

    @XmlElement(name = "id")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @XmlElement(name = "nickname")
    public String getNickName() {
        return nickname;
    }

    public void setNickName(String nickname) {
        this.nickname = nickname;
    }

    @XmlElement(name = "email")
    public String getEMail() {
        return email;
    }

    public void setEMail(String email) {
        this.email = email;
    }

    @XmlElement(name = "password")
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

在创建/注册用户期间，必须提供密码，但稍后，在询问用户信息时，XML 不应包含密码元素。 是否可以将元素定义为只写？

最佳答案

注意:我是 EclipseLink JAXB (MOXy) JAXB 2 (JSR-222) 的领导和成员专家组。

MOXy 有一个 @XmlReadOnly 扩展。用 @XmlReadOnly 注释的字段/属性将在解码(读取)期间填充，但不会在编码期间写入。

用户

package forum10208143;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import org.eclipse.persistence.oxm.annotations.XmlReadOnly;

/**
 * @author Martin Burchard
 * 
 */
@XmlRootElement(name = "user")
public class User {
    private String id;
    private String nickname;
    private String email;
    private String password;

    @XmlElement(name = "id")
    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    @XmlElement(name = "nickname")
    public String getNickName() {
        return nickname;
    }

    public void setNickName(String nickname) {
        this.nickname = nickname;
    }

    @XmlElement(name = "email")
    public String getEMail() {
        return email;
    }

    public void setEMail(String email) {
        this.email = email;
    }

    @XmlElement(name = "password")
    @XmlReadOnly
    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

}

jaxb.properites

要将 MOXy 指定为您的 JAXB 提供者，您需要在与您的域模型相同的包中添加一个名为 jaxb.properties 的文件，其中包含以下条目:

javax.xml.bind.context.factory = org.eclipse.persistence.jaxb.JAXBContextFactory

演示

package forum10208143;

import java.io.File;
import javax.xml.bind.*;

public class Demo {

    public static void main(String[] args) throws Exception {
        JAXBContext jc = JAXBContext.newInstance(User.class);

        Unmarshaller unmarshaller = jc.createUnmarshaller();
        File xml = new File("src/forum10208143/input.xml");
        User user = (User) unmarshaller.unmarshal(xml);

        System.out.println(user.getPassword());

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(user, System.out);
    }

}

输入.xml

<?xml version="1.0" encoding="UTF-8"?>
<user>
    <id>jdoe</id>
    <nickname>Jane</nickname>
    <email>jane.doe@example.com</email>
    <password>secret</password>
</user>

输出

secret
<?xml version="1.0" encoding="UTF-8"?>
<user>
   <email>jane.doe@example.com</email>
   <id>jdoe</id>
   <nickname>Jane</nickname>
</user>

关于java - 注解@XmlElement 只写？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10208143/