java - 无法从 xml 解码元素列表

Question

我尝试通过标准 javax 库解码 SOAP 响应。响应的xml是这样的

    <?xml version="1.0" encoding="UTF-8"?>
    <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
      <s:Header>
        <ActivityId xmlns="http://schemas.microsoft.com/2004/09/ServiceModel/Diagnostics" CorrelationId="465733a9-9fb7-4287-89c5-5250d5697194">00000000-0000-0000-0000-000000000000</ActivityId>
      </s:Header>
      <s:Body>
        <BResponse xmlns="http://tempuri.org/">
          <Result xmlns:a="http://someurl.ru/">
            <a:Element>
              <a:ID>11488477</a:ID>
              <a:Name>Object 1</a:Name>
            </a:Element>
            <a:Element>
              <a:ID>11488453</a:ID>
              <a:Name>Object 2</a:Name>
            </a:Element>
          </Result>
        </BResponse>
      </s:Body>
    </s:Envelope>

我的代码可以在那里访问 http://tpcg.io/JXuwHB我做错了什么？

    package test;

    import java.io.ByteArrayInputStream;
    import java.util.List;

    import javax.xml.bind.*;
    import javax.xml.bind.annotation.*;
    import javax.xml.soap.*;

    @XmlRootElement ( name = "Element" )
    class Element { 
        @Override
        public String toString() {
            return "Element [id=" + id + ", name=" + name + "]";
        }

        @XmlElement ( name = "ID" )
        public int id;

        @XmlElement ( name = "Name" )
        public String name; 
    }

    @XmlRootElement ( name = "BResponse", namespace = "http://tempuri.org/" )
    class BResponse {

        @XmlElementWrapper ( name = "Result", namespace = "http://someurl.ru/" )
        @XmlElement ( name = "Element", type = Element.class )
        public List<Element> result;

    }

    public class Test {

        public static void main(String[] args) throws Exception {
                System.out.println(res);
                SOAPMessage message = MessageFactory.newInstance().createMessage(new MimeHeaders(),new ByteArrayInputStream(res.getBytes("utf-8")));
                Unmarshaller unmarshaller = JAXBContext.newInstance(BResponse.class).createUnmarshaller();
                BResponse bResponse = (BResponse)unmarshaller.unmarshal(message.getSOAPBody().extractContentAsDocument());
                for ( Element element : bResponse.result )
                    System.out.println(element);
        }   

        public static String res =
            "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\r\n" +
            "<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\">\r\n" + 
            "  <s:Header>\r\n" + 
            "    <ActivityId xmlns=\"http://schemas.microsoft.com/2004/09/ServiceModel/Diagnostics\" CorrelationId=\"465733a9-9fb7-4287-89c5-5250d5697194\">00000000-0000-0000-0000-000000000000</ActivityId>\r\n" + 
            "  </s:Header>\r\n" + 
            "  <s:Body>\r\n" + 
            "    <BResponse xmlns=\"http://tempuri.org/\">\r\n" + 
            "      <Result xmlns:a=\"http://someurl.ru/\">\r\n" + 
            "        <a:Element>\r\n" +
            "          <a:ID>11488477</a:ID>\r\n" + 
            "          <a:Name>Object 1</a:Name>\r\n" + 
            "        </a:Element>\r\n" + 
            "        <a:Element>\r\n" + 
            "          <a:ID>11488453</a:ID>\r\n" + 
            "          <a:Name>Object 2</a:Name>\r\n" + 
            "        </a:Element>\r\n" + 
            "      </Result>\r\n" + 
            "    </BResponse>\r\n" + 
            "  </s:Body>\r\n" + 
            "</s:Envelope>";    

    }

我像标准示例中一样注释了所有元素，并尝试通过 jaxb 对其进行解码，但解码器返回 null 结果

Exception in thread "main" java.lang.NullPointerException at test.Test.main(Test.java:39)

Answer 1

编写正确的注释有帮助

    @XmlRootElement( name = "Element", namespace = "http://someurl.ru/" )
    class Element { 
        @Override
        public String toString() {
            return "Element [id=" + id + ", name=" + name + "]";
        }

        @XmlElement ( name = "ID", namespace = "http://someurl.ru/" )
        public int id;

        @XmlElement ( name = "Name", namespace = "http://someurl.ru/" )
        public String name; 
    }


    @XmlRootElement ( name = "BResponse", namespace = "http://tempuri.org/" )
    class BResponse {

        @XmlElementWrapper ( name = "Result", namespace = "http://tempuri.org/" )
        @XmlElement ( name = "Element" , type = Element.class, namespace = "http://someurl.ru/" )
        public List<Element> result;

    }

并且需要创建包含内容的 package-info.java

    @javax.xml.bind.annotation.XmlSchema (
        xmlns = {               
                @javax.xml.bind.annotation.XmlNs ( prefix = "", namespaceURI = "http://tempuri.org/" ),             
                @javax.xml.bind.annotation.XmlNs ( prefix = "a", namespaceURI = "http://someurl.ru/" )
        }
    )
    package test;

其中描述了 xml 前缀和命名空间