org.springframework.oxm.UnmarshallingFailureException：解组时出现 NPE。使用 spring resttemplate 和 jaxb

Question

我正在尝试解组以下 xml

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<InfoResult>
    <resultCode>OK</resultCode>
    <msisdn>263771222608</msisdn>
    <make>Samsung</make>
    <model>Galaxy Grand Neo Plus I9060I</model>
    <settings>
        <setting>Internet</setting>
        <setting>Internet &amp; MMS</setting>
        <setting>MMS</setting>
        <setting>WAP</setting>
    </settings>
</InfoResult>

带标题

Content-Type →application/vnd.mobilethink.setting-v1+xml

如果首先将 restTemplate 解释为 json 则会出现问题，因此我尝试使用此处找到的代码强制内容处理程序： Ignoring DTDs when unmarshalling with EclipseLink MOXy

但我收到了编组错误。所以我深入研究了编组并手动完成：

private Jaxb2Marshaller marshaller=new Jaxb2Marshaller();

public Object unmarshal(String xmlString) {
    return marshaller.unmarshal(new StreamSource(new StringReader(xmlString)));
}

public InfoResult getSettingsInfo(String msisdn) {
    MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
    headers.add("Accept", "application/vnd.mobilethink.setting-v1+xml");
    HttpEntity<String> entity = new HttpEntity<>(headers);
    ResponseEntity<String> infoResultResponseEntity = restTemplate.exchange(INFO_REQUEST_URL, HttpMethod.GET, entity, String.class, msisdn);
    String data = infoResultResponseEntity.getBody();
    Object o = unmarshal(data);
    return new InfoResult();
}

但我仍然得到一个编组例外：

org.springframework.oxm.UnmarshallingFailureException: NPE while unmarshalling. This can happen on JDK 1.6 due to the presence of DTD declarations, which are disabled.; nested exception is java.lang.NullPointerException
        at org.springframework.oxm.jaxb.Jaxb2Marshaller.unmarshal(Jaxb2Marshaller.java:777)
        at org.springframework.oxm.jaxb.Jaxb2Marshaller.unmarshal(Jaxb2Marshaller.java:753)

请帮忙指出这里的错误代码。

Answer 1

我最近也遇到了类似的问题。

从发布的代码看来，Jaxb2Marshaller 没有正确初始化。需要设置contextPath或documentation中提到的classesToBeBound属性。

正确的初始化代码示例：

Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
marshaller.setClassesToBeBound(RootEntity.class);
marshaller.afterPropertiesSet();