JAXB Unmarshall到列表

Question

我想解析這個XML到Java對象，一個包含EmailAdresses列表的Customer對象。

<customer> 
<emailAddresses>janed@example.com</emailAddresses> 
<emailAddresses>jdoe@example.org</emailAddresses> 
</customer> 

經與列表中的一個問題，我得到的列表項（2），但爲EmailAddresses變量的值正確的號碼是空

Customer.java

@XmlRootElement(name = "customer") 
public class Customer 
{ 
    private List<EmailAddress> emailAddresses; 

    public Customer() 
    { 
     emailAddresses = new ArrayList<EmailAddress>(); 
    } 

    public List<EmailAddress> getEmailAddresses() 
    { 
     return emailAddresses; 
    } 

    public void setEmailAddresses(List<EmailAddress> emailAddresses) 
    { 
     this.emailAddresses = emailAddresses; 
    } 
} 

EmailAddress.java

public class EmailAddress 
{ 
    private String emailAddresses; 

    public String getEmailAddresses() 
    { 
     return emailAddresses; 
    } 

     public void setEmailAddresses(String emailAddresses) 
    { 
     this.emailAddresses = emailAddresses; 
    } 
} 

失敗的單元測試

@Test 
public void shouldDeserialiseCusomerXMLToObject() throws JAXBException 
{ 
    String xml = "<customer>" 
      + " <emailAddresses>janed@example.com</emailAddresses>" 
      + " <emailAddresses>jdoe@example.org</emailAddresses>" 
      + "</customer>"; 

    JAXBContext jaxbContext = JAXBContext.newInstance(Customer.class); 
    Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller(); 

    StringReader reader = new StringReader(xml); 
    Customer msg = (Customer) jaxbUnmarshaller.unmarshal(reader); 

    // This passes, I have 2 emailAddresses 
    assertEquals(2, msg.getEmailAddresses().size()); 

    // This fails, I have a null pointer instead of the email address 
    assertEquals("janed@example.com", msg.getEmailAddresses().get(0).getEmailAddresses()); 
} 

Answer 1

的EmailAddress的emailAddresses欄默認是作爲子處理，期待XML是：

<customer> 
    <emailAddresses> 
     <emailAddresses>janed@example.com</emailAddresses> 
    </emailAddresses> 
    <emailAddresses> 
     <emailAddresses>jdoe@example.org</emailAddresses> 
    </emailAddresses> 
</customer> 

由於您的外部<emailAddresses>元素不包含內部<emailAddresses>元素，因此該字段永遠不會被分配。

你想要的EmailAddress的emailAddresses場是（外）<emailAddresses>元素的值，所以你必須，通過指定@XmlValue註解告訴JAXB：

@XmlValue 
public String getEmailAddresses() 
{ 
    return emailAddresses; 
} 

---

的@XmlValue註解在與@XmlAttribute結合時特別有用，以支持如下的XML：

<Person sex="male" age="25">John Doe</Person> 

那麼類將然後是：

public class Person { 
    public enum Sex { 
     @XmlEnumValue("male") MALE, 
     @XmlEnumValue("female") FEMALE, 
    } 
    @XmlAttribute 
    private Sex sex; 
    @XmlAttribute 
    private int age; 
    @Value 
    private String name; 
} 

Answer 2

你有太多的電子郵件地址的水平。

如果您的電子郵件地址的列表改變爲一個字符串列表，像

@XmlRootElement(name = "customer") 
public class Customer 
{ 
    private List<String> emailAddresses; 

    public Customer() 
    { 
     emailAddresses = new ArrayList<String>(); 
    } 

    public List<String> getEmailAddresses() 
    { 
     return emailAddresses; 
    } 

    public void setEmailAddresses(List<String> emailAddresses) 
    { 
     this.emailAddresses = emailAddresses; 
    } 
}