使用Jackson XmlMapper將XML反序列化爲POJO

Question

使用Jackson XmlMapper註解，我將如何將此XML反序列化爲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> 

我嘗試使用這樣的：

@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; 
} 

當我試圖用XmlMapper的readValue（），我得到以下錯誤：

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) 

Answer 1

你POJO類不適合你的XML。結構比你想象的要簡單。見下面的例子：

@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 
} 

簡單的用法：

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

上述程序打印（您XML）：

OpenCredentials{credentials=[Credentials{priv='write', type='internal', user='Username1', client_token='abcplaudzrbcy37c', client_secret='0cxDE3LE0000='}, Credentials{priv='read', type='internal', user='Username1', client_token='123plaudzrbcy37c', client_secret='0cxDE3LE1234='}, Credentials{priv='none', type='internal', user='Username1', client_token='000plaudzrbcy37c', client_secret='0cxDE3LEabcd='}]} 

參見：

1. jackson-dataformat-xml。
2. Home: Jackson XML databind Wiki。