java JAXB解组无法正常工作

Question

我试图使用JAXB将XML转换为对象，我的XML如下所示：

<entityResource>
   <Item xsi:type="objectPermissionImpl">
      <permissionMask>0</permissionMask>
      <permissionRecipient xsi:type="roleImpl">
        <externallyDefined>false</externallyDefined>
        <roleName>ROLE_USER</roleName>
      </permissionRecipient>
      <URI>repo:/public/adhoc/topics/JSDiagnosticTopic</URI>
   </Item>
   <Item xsi:type="objectPermissionImpl">
      <permissionMask>0</permissionMask>
      <permissionRecipient xsi:type="roleImpl">
        <externallyDefined>false</externallyDefined>
        <roleName>ROLE_ADMINISTRATOR</roleName>
      </permissionRecipient>
      <URI>repo:/public/adhoc/topics/JSDiagnosticTopic</URI>
   </Item>
</entityResource>

所以我创建了3个java类：EntityResource。java，项目。java和PermissionRecipient。java，如下所示：

整个资源。java

import java.util.List;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="entityResource")
public class EntityResource {

    List<Item> ls_Item;

    public EntityResource() {
    }

    public List<Item> getLs_Item() {
        return ls_Item;
    }

    @XmlElement(name="Item")
    public void setLs_Item(List<Item> ls_Item) {
        this.ls_Item = ls_Item;
    }

    @Override
    public String toString() {
        return "EntityResource [ls_Item=" + ls_Item + "]";
    }

}

项目。java

package model;

import java.util.List;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name="Item")
public class Item {

    int permissionMask;
    List<PermissionRecipient> ls_permissionRecipient;
    String URI;

    public Item() {

    }

    public int getPermissionMask() {
        return permissionMask;
    }

    @XmlElement(name="permissionMask")
    public void setPermissionMask(int permissionMask) {
        this.permissionMask = permissionMask;
    }

    public List<PermissionRecipient> getLs_permissionRecipient() {
        return ls_permissionRecipient;
    }

    @XmlElement(name="permissionRecipient")
    public void setLs_permissionRecipient(
            List<PermissionRecipient> ls_permissionRecipient) {
        this.ls_permissionRecipient = ls_permissionRecipient;
    }

    public String getURI() {
        return URI;
    }

    @XmlElement(name="URI")
    public void setURI(String uRI) {
        URI = uRI;
    }

    @Override
    public String toString() {
        return "Item [permissionMask=" + permissionMask
                + ", ls_permissionRecipient=" + ls_permissionRecipient
                + ", URI=" + URI + "]";
    }





}

许可接收人。java

package model;

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

@XmlRootElement(name="permissionRecipient")
public class PermissionRecipient {

    String roleName;
    boolean externallyDefined;

    public PermissionRecipient() {

    }

    public boolean isExternallyDefined() {
        return externallyDefined;
    }

    @XmlAttribute(name="externallyDefined")
    public void setExternallyDefined(boolean externallyDefined) {
        this.externallyDefined = externallyDefined;
    }

    public String getRoleName() {
        return roleName;
    }

    @XmlAttribute(name="roleName")
    public void setRoleName(String rolename) {
        this.roleName = rolename;
    }

    @Override
    public String toString() {
        return "PermissionRecipient [externallyDefined=" + externallyDefined
                + ", roleName=" + roleName + "]";
    }


}

所有的工作和我得到一个EntityResource对象包含该项，但是EntityResource的Item属性的permissionRecipient属性不包含他的属性（roleName和externallyDefined）

我的解组代码如下：

JAXBContext jaxbContext = JAXBContext
                    .newInstance(EntityResource.class);
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            EntityResource resourceDescriptors = (EntityResource) jaxbUnmarshaller
                    .unmarshal(conn.getInputStream());// conn is an HttpURLConnection

项的toString()函数返回以下结果：

[Item 
[permissionMask=0, 
permissionRecipient=PermissionRecipient [externallyDefined=false, roleName=null], 
URI=repo:/public/adhoc/topics/JSDiagnosticTopic], 

Item 
[permissionMask=0, 
permissionRecipient=PermissionRecipient [externallyDefined=false, roleName=null], 
URI=repo:/public/adhoc/topics/JSDiagnosticTopic]]

因为你可以在每个项目中标记[externallyDefined=false, roleName=null]，为什么？我犯了什么错误？如果这里有人能帮我解决问题，谢谢你，祝你好运

Answer 1

用@XmlAttribute而不是@XmlElement映射了roleName和externallyDefined

调试提示

当对象模型没有按预期解组时，填充它并将其编组为XML，然后将输出与输入进行比较

Answer 2

在我们的例子中，我们发现了一个不同的问题，即我们有一个xml标记，如

<tag></tag> 

并定义了一个带有名称标记的java类。稍后，当我们尝试在java中使用它时，我们声明了如下所示的变量

Tag tag; //didn't worked

和Java类，如下所示

@XmlRootElement(name = "Tag")
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "Tag", propOrder = {

})
public class Tag{}

取消编组不起作用，也没有加载值。我们将变量名从“tag”改为“tag”，宾果！成功了

Tag Tag; //worked

另一个类似的情况是我们有标签名，比如

<tagNew></tagNew>

Java类为TagNew，变量名为TagNew，运行良好

@XmlRootElement(name = "TagNew")
@XmlAccessorType(XmlAccessType.FIELD)
@XmlType(name = "TagNew", propOrder = {

})
public class TagNew{}

TagNew tagNew; // worked fine

也许我们仍然需要学习！这就是JaxB如何使用命名约定