Marshall对象字段作为属性 [英] Marshall object field as attribute

问题描述

到目前为止，我使用JAXB对我的POJO进行编组：

  @XmlRootElement 
 public class Local {
私人实体实体; 
 
 public void setEntity（实体实体）{
 this.entity = entity; 
} 
 
 @XmlElement 
 public Entity getEntity（）{
 return entity; 
} 
} 
  

和

  @XmlRootElement 
 public class Entity {
 private String name; 
私人字符串评论; 
 
 public void setName（String name）{
 this.name = name; 
} 
 
 @XmlAttribute 
 public String getName（）{
 return this.name; 
} 
 
 public void setComment ... 
 
 @XmlAttribute 
 public void getComment ... 
} 
  

有了这个，我得到这样的结果：

 <局部> 
< entity name =comment =>< / entity> 
< / local> 
  

但是，我更希望将name属性作为本地属性：

 < local entityName =entityComment =>< / local> 
  

XmlJavaTypeAdapter是一个好的开始方式吗？

谢谢，
Alex

解决方案

有几种不同的选项可以处理这个用例： / p>

选项＃1 - XmlAdapter（任何JAXB实现）

您可以使用此用例的 XmlAdapter 。只要只有一个属性值来自实体对象，这将有效：

EntityAdapter

  import javax.xml.bind.annotation.adapters.XmlAdapter; 
 
公共类EntityAdapter扩展XmlAdapter< String，Entity> {
 
 @Override 
 public String marshal（Entity entity）抛出异常{
 if（null == entity）{
返回null; 
} 
返回entity.getName（）; 
} 
 
 @Override 
 public Entity unmarshal（String name）throws Exception {
 Entity entity = new Entity（）; 
 entity.setName（name）; 
返回实体; 
} 
 
} 
  

本地

使用 @XmlJavaTypeAdapter 注释将XmlAdapter与字段/属性链接：

  import javax.xml.bind.annotation.XmlAttribute; 
 import javax.xml.bind.annotation.XmlRootElement; 
 import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter; 
 
 @XmlRootElement 
 public class Local {
 private Entity entity; 
 
 public void setEntity（实体实体）{
 this.entity = entity; 
} 
 
 @XmlAttribute 
 @XmlJavaTypeAdapter（EntityAdapter.class）
 public Entity getEntity（）{
 return entity; 
} 
 
} 
  

For更多信息

• http://blog.bdoughan.com/2010/07/xmladapter-jaxbs-secret-weapon.html


• http://blog.bdoughan.com/ 2010/12 / jaxb-and-immutable-objects.html

---

选项＃2 - @XmlPath（EclipseLink JAXB（MOXy）

或者，如果您使用 EclipseLink JAXB（MOXy） ，您可以使用 @XmlPath extension。这对于 Entity 对象有用，对应多个XML属性：

本地

指定XPath。表示将子内容写入父元素

  import javax.xml.bind.annotation。*; 
 import org.eclipse.persistence.oxm.annotations。*; 
 
 @XmlRootElement 
 public class Local {
 private Entity entity; 
 
 public void setEntity（实体实体）{
 this.entity = entity; 
} 
 
 @XmlPath（。）
 public Entity getEntity（）{
 return entity; 
} 
} 
  

实体

  public class Entity {
 private String name; 
私人字符串评论; 
 
 public void setName（String name）{
 this.name = name; 
} 
 
 @XmlAttribute（name =entityName）
 public String getName（）{
 return this.name; 
} 
 
 public void setComment（String comment）{
 this.comment = comment; 
} 
 
 @XmlAttribute（name =entityComment）
 public String getComment（）{
 return this.comment; 
} 
} 
  

更多信息

• http://bdoughan.blogspot.com/2010/07/xpath-based-mapping.html


• http://blog.bdoughan.com/2010/09/xpath- based-mapping-geocode-example.html


• http://blog.bdoughan.com/2011/03/map-to-element-based-on-attribute-value.html


• http：// blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html

Here is what I have so far to marshall my POJO using JAXB :

@XmlRootElement
public class Local {
    private Entity entity;

    public void setEntity(Entity entity) {
        this.entity = entity;
    }

    @XmlElement
    public Entity getEntity() {
        return entity;
    }
}

and

@XmlRootElement
public class Entity {
    private String name;
    private String comment;

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

    @XmlAttribute
    public String getName(){
        return this.name;
    }

    public void setComment...

    @XmlAttribute
    public void getComment...
}

With that, I get something like this:

<local>
    <entity name="" comment=""></entity>
</local>

However, I would prefer to have the name attribute as an attribute of the local:

<local entityName="" entityComment=""></local>

Is the XmlJavaTypeAdapter a good way to begin with?

Thanks, Alex

解决方案

There are a couple of different options to handle this use case:

Option #1 - XmlAdapter (Any JAXB implementation)

You could use an XmlAdapter for this use case. This will work as long as only one attribute value comes from the Entity object:

EntityAdapter

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class EntityAdapter extends XmlAdapter<String, Entity>{

    @Override
    public String marshal(Entity entity) throws Exception {
        if(null == entity) {
            return null;
        }
        return entity.getName();
    }

    @Override
    public Entity unmarshal(String name) throws Exception {
        Entity entity = new Entity();
        entity.setName(name);
        return entity;
    }

}

Local

The XmlAdapter is linked with the field/property using the @XmlJavaTypeAdapter annotation:

import javax.xml.bind.annotation.XmlAttribute;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@XmlRootElement
public class Local {
    private Entity entity;

    public void setEntity(Entity entity) {
        this.entity = entity;
    }

    @XmlAttribute
    @XmlJavaTypeAdapter(EntityAdapter.class)
    public Entity getEntity() {
        return entity;
    }

}

For More Information

• http://blog.bdoughan.com/2010/07/xmladapter-jaxbs-secret-weapon.html
• http://blog.bdoughan.com/2010/12/jaxb-and-immutable-objects.html

---

Option #2 - @XmlPath (EclipseLink JAXB (MOXy)

Alternatively if you are using EclipseLink JAXB (MOXy), the you could use the @XmlPath extension. This is useful with the Entity object corresponds to multiple XML attributes:

Local

Specifying the XPath "." indicated that the child contents will be written into the parent element

import javax.xml.bind.annotation.*;
import org.eclipse.persistence.oxm.annotations.*;

@XmlRootElement
public class Local {
    private Entity entity;

    public void setEntity(Entity entity) {
        this.entity = entity;
    }

    @XmlPath(".")
    public Entity getEntity() {
        return entity;
    }
}

Entity

public class Entity {
    private String name;
    private String comment;

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

    @XmlAttribute(name="entityName")
    public String getName(){
        return this.name;
    }

    public void setComment(String comment){
        this.comment = comment;
    }

    @XmlAttribute(name="entityComment")
    public String getComment(){
        return this.comment;
    }
}

For More Information

• http://bdoughan.blogspot.com/2010/07/xpath-based-mapping.html
• http://blog.bdoughan.com/2010/09/xpath-based-mapping-geocode-example.html
• http://blog.bdoughan.com/2011/03/map-to-element-based-on-attribute-value.html
• http://blog.bdoughan.com/2011/05/specifying-eclipselink-moxy-as-your.html

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