Spring MVC 映射 Guava Multimap

Question

我的控制器无法映射来自前端的 Google Guava Multimap。我从我的 Javascript 发送这个对象：

{1:[true,false], 2:[false,true], ...}. 

如果我使用标准

java.util.Map<Long, List<Boolean>> 

一切正常。但不是 Guava Multimap。我是否必须配置 Spring 才能使用一些自定义转换器，或者有什么问题？

控制器是：

@RequestMapping(path = "/myurl", method = RequestMethod.POST, produces = CotrollerKonstanten.JSON_UTF8)
public long myMethod(@RequestBody MappingDto mappingDto) {
  //...
}

我的例外是：

org.springframework.http.converter.HttpMessageNotReadableException: Could not read document: 
  Can not construct instance of com.google.common.collect.Multimap, problem:
  abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information
at [Source: java.io.PushbackInputStream@4b9c2db; line: 1, column: 13] (through reference chain: ...myClass); 
nested exception is com.fasterxml.jackson.databind.JsonMappingException: 
  Can not construct instance of com.google.common.collect.Multimap, problem: abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information

Answer 1

你register the Guava module了吗？默认情况下，Jackson（以及 Spring）不支持序列化或反序列化为 Guava 数据类型。

Guava 模块可能适合您，也可能不适合您，具体取决于您想要的Multimap 的实现方式——并非所有数据类型都已实现。