java - 无法使用 jackson 解析 xml 根元素

Question

测试 Bean

@JacksonXmlRootElement(localName = "DATA_RECORD")
public class TestBean{
    @JacksonXmlProperty(localName="ERROR_MESSAGE_CODE")
    private String error_message_code;
    @JacksonXmlProperty(localName="ERROR_MESSAGE")
    private String error_message;
    //...getter/setter
}

XML 示例

String xml = "<?xml version=\"1.0\" encoding=\"Windows-31J\" standalone=\"no\"?>"
            + "<Message xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" "
            //+">"
            + "xsi:noNamespaceSchemaLocation=\"TEST.xsd\">" // if comment out this,it will work.
            + "<DATA_RECORD>"
            + "<ERROR_MESSAGE>some message</ERROR_MESSAGE>"
            + "<ERROR_MESSAGE_CODE>CODE111</ERROR_MESSAGE_CODE>"
            + "</DATA_RECORD>"
            + "</Message>";

反序列化

XmlMapper xmlMapper = new XmlMapper();
//xmlMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
xmlMapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
TestBean test = xmlMapper.readValue(xml, TestBean.class);
log.debug(test.toString());

我从 Junit 运行它，并得到如下异常:

Root name 'noNamespaceSchemaLocation' does not match expected ('DATA_RECORD') ....

如果我从 String xml 中删除 xsi:noNamespaceSchemaLocation="TEST.xsd"，它将正常工作。

对此有什么想法吗？感谢您的帮助。

Answer 1

根据docs ，当您指定 UNWRAP_ROOT_VALUE 时，Jackson(此处为 XML，而不是 JSON)

Will verify that the root JSON value is a JSON Object, and that it has a single property with expected root name. If not, a JsonMappingException is thrown;

在这种情况下，根 Message 除了 DATA_RECORD 之外还有另一个属性，即名称为 noNamespaceSchemaLocation 的 XML 属性，并指定为 抛出 JsonMappingException。

恐怕您必须解析Message并从那里获取TestBean。例如:

@JacksonXmlRootElement
class Message {
    @JacksonXmlProperty(localName = "DATA_RECORD")
    private TestBean dataRecord;
}

class TestBean {
    @JacksonXmlProperty(localName = "ERROR_MESSAGE_CODE")
    private String error_message_code;
    @JacksonXmlProperty(localName = "ERROR_MESSAGE")
    private String error_message;
}

和

xmlMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
Message test = xmlMapper.readValue(xml, Message.class);
log.debug(test.getDataRecord().toString());