杰克逊解析json与unwraping root，但没有能力设置@JsonRootName [英] Jackson parse json with unwraping root, but without ability to set @JsonRootName
问题描述
其他服务回复
<transaction><trxNumber>1243654</trxNumber><type>INVOICE</type></transaction>
或JSON：
{"transaction":{"trxNumber":1243654,"type":"INVOICE"}}
使用时没有问题：
mapper.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true)
结果类
@JsonRootName("transaction")
public class Transaction {
private String trxNumber;
private String type;
//getters and setters
}
但实际上我应该使用交易来自第三方jar的类，与上面的类似，但没有@JsonRootName（transaction）注释。
But actually I should use the Transaction class from 3rd party jar, which is exact like above, but has no @JsonRootName("transaction") annotation.
所以我最终with
Could not read JSON: Root name 'transaction' does not match expected ('Transaction') for type...
有没有办法强制Jackson解析到Transaction类而不向Transaction类本身添加任何东西（如我把这个文件作为二进制jar的一部分）？
Is there any ways to force Jackson parse to Transaction class without adding any stuff to the Transaction class itself (as I get this file as part of a binary jar)?
我尝试过定制的PropertyNamingStrategy，但它似乎只能用字段和getter / setter名称来做，但是不是班级名称。
I've tried custom PropertyNamingStrategy, but it seems has to do only with field and getter/setter names, but not class names.
Java7，Jackson 2.0.5。
Java7, Jackson 2.0.5.
有什么建议吗？谢谢。
推荐答案
你可以用 mixin 功能。您可以像这样创建简单的接口/抽象类：
You can do it with mixin feature. You can create simple interface/abstract class like this:
@JsonRootName("transaction")
interface TransactionMixIn {
}
现在，您必须配置 ObjectMapper object：
Now, you have to configure ObjectMapper object:
ObjectMapper mapper = new ObjectMapper();
mapper.enable(DeserializationFeature.UNWRAP_ROOT_VALUE);
mapper.addMixInAnnotations(Transaction.class, TransactionMixIn.class);
最后你可以用它来反序列化JSON：
And finally you can use it to deserialize JSON:
mapper.readValue(json, Transaction.class);
第二个选项 - 你可以写自定义反序列化器 Transaction class。
Second option - you can write custom deserializer for Transaction class.
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