CODEWITHSUNDEEP
spring-mvcmappingguavamultimap
Ewgenij Sokolovski
Ewgenij Sokolovski

Reputation: 967

Spring MVC mapping Guava Multimap

My controller can't map a Google Guava Multimap coming from the frontend. I send from my Javascript this object: 

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

If I use a standard 

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

everything works fine. But not with the Guava Multimap. Do I have to configure Spring to use some custom converter, or what is the problem?

The controller is:

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

My exception is: 

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

Upvotes: 2

Views: 1120

Answers (1)

Dave L.
Dave L.

Reputation: 9801

Did you register the Guava module? By default, Jackson (and hence Spring) does not support serializing or deserializing to Guava datatypes.

The Guava module may or may not work for you depending on what implementation of Multimap you want -- not all datatypes are implemented.

Upvotes: 5

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