spring-mvc - Spring MVC 映射 Guava Multimap

Question

我的 Controller 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 Guava Multimap 则不然。我是否必须配置 Spring 才能使用某些自定义转换器，或者有什么问题？

Controller 是:

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

我的异常(exception)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

你有吗register the Guava module ？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 模块可能适合也可能不适合您，具体取决于您想要哪种 Multimap 实现 - 并非所有数据类型都已实现。