使用 Jackson XmlMapper 将 XML 反序列化为 POJO

Posted 2023-02-26

【中文标题】使用 Jackson XmlMapper 将 XML 反序列化为 POJO

【英文标题】：XML deserialization to POJO using Jackson XmlMapper

【发布时间】：2014-10-22 18:39:50

【问题描述】：

使用 Jackson XmlMapper 注释，我如何将此 XML 反序列化为 pojo？

<?xml version="1.0" encoding="UTF-8"?>
<open>
   <creds priv="write" type="internal">
      <user>Username1</user>
      <client_token>abcplaudzrbcy37c</client_token>
      <client_secret>0cxDE3LE0000=</client_secret>
   </creds>
   <creds priv="read" type="internal">
      <user>Username1</user>
      <client_token>123plaudzrbcy37c</client_token>
      <client_secret>0cxDE3LE1234=</client_secret>
   </creds>
   <creds priv="none" type="internal">
      <user>Username1</user>
      <client_token>000plaudzrbcy37c</client_token>
      <client_secret>0cxDE3LEabcd=</client_secret>
   </creds>
</open>

我尝试使用这样的东西：

@JacksonXmlRootElement(localName = "Open")
public class OpenCredentials 

    @JacksonXmlProperty(localName = "Credentials")
    private Credentials[] credentials;




class Credentials 

    @JacksonXmlProperty(isAttribute = true)
    private String priv;

    @JacksonXmlProperty(isAttribute = true)
    private String type;

    @JacksonXmlProperty(localName = "Creds")
    private Creds[] creds;



class Creds 

    @JacksonXmlText(value = true)
    private String user;

    @JacksonXmlText(value = true)
    private String client_token;

    @JacksonXmlText(value = true)
    private String client_secret;

当我尝试使用 XmlMapper 的 readValue() 时，出现以下错误：

com.fasterxml.jackson.databind.JsonMappingException: Duplicate property '' for [simple type, class com.company.data.utils.api.Creds]
at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCache2(DeserializerCache.java:268)
at com.fasterxml.jackson.databind.deser.DeserializerCache._createAndCacheValueDeserializer(DeserializerCache.java:243)

【参考方案1】：

您的POJO 课程不适合您的XML。结构比你想象的要简单。见下例：

@JacksonXmlRootElement(localName = "open")
class OpenCredentials 

    @JacksonXmlProperty(localName = "creds")
    @JacksonXmlElementWrapper(useWrapping = false)
    private Credentials[] credentials;

    //getters, setters, toString



class Credentials 

    @JacksonXmlProperty(isAttribute = true)
    private String priv;

    @JacksonXmlProperty(isAttribute = true)
    private String type;

    private String user;

    @JacksonXmlProperty(localName = "client_token")
    private String clientToken;

    @JacksonXmlProperty(localName = "client_secret")
    private String clientSecret;

    //getters, setters, toString

简单用法：

XmlMapper mapper = new XmlMapper();
OpenCredentials openCredentials = mapper.readValue(XML, OpenCredentials.class);
System.out.println(openCredentials);

上面的程序打印（为您的XML）：

OpenCredentialscredentials=[Credentialspriv='write', type='internal', user='Username1', client_token='abcplaudzrbcy37c', client_secret='0cxDE3LE0000=', Credentialspriv='read', type='internal', user='Username1', client_token='123plaudzrbcy37c', client_secret='0cxDE3LE1234=', Credentialspriv='none', type='internal', user='Username1', client_token='000plaudzrbcy37c', client_secret='0cxDE3LEabcd=']

另见：

jackson-dataformat-xml。 Home: Jackson XML databind Wiki。

【讨论】：

我得到“无法识别的字段”将 localName 设置为 JacksonXmlElementWrapper 注释，拆分为 @MichalZiober 示例后，反序列化工作正常