InvalidDataAccessApiUsageException：没有为com.mongodb.BasicDBList类找到持久性实体信息

Question

I am trying to insert an array of json objects into mongodb. I pass the array with a POST request, using Spring

My object

@Document(collection = "Users")
public class User {
  private String name;
  private String number;
//constructors, getters, setters
}

My spring controller

@RestController
public class UserController {

  @RequestMapping(value="/postUser", method = RequestMethod.POST)
  public void postUser(@RequestBody BasicDBList users){
    ApplicationContext ctx =
      new AnnotationConfigApplicationContext(SpringMongoConfig.class);
    MongoOperations mongoOperation =
      (MongoOperations) ctx.getBean("mongoTemplate");
    mongoOperation.insert(users);
  }
}

This is my json

[
    {
        "name" : "a",
        "number" : "1"
    },
    {
        "name" : "c",
        "number" : "3"      
    }
]

What I get in return is

{
    "timestamp": 1499161260902,
    "status": 500,
    "error": "Internal Server Error",
    "exception": "org.springframework.dao.InvalidDataAccessApiUsageException",
    "message": "No Persistent Entity information found for the class com.mongodb.BasicDBList",
    "path": "/postUser"
}

There is no problem if I do

public void postUser(@RequestBody User users)

and insert a single user. Why doesn't it work?

Answer 1

When you add @RequestBody before the parameter, HttpMessageConvertor will try to convert json string to the specified type - BasicDBList . The json string may not match BasicDBList , so the conversion failed. You can use this:

public void postUser(@RequestBody List<User> users)

Answer 2

Actually, Spring data cannot determine the collection name to save BasicDBList.
This is not related to HttpMessageConverter
You can check more here: Insert DBObject into MongoDB using Spring Data

Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: No Persitent Entity information found for the class com.mongodb.BasicDBObject at org.springframework.data.mongodb.core.MongoTemplate.determineCollectionName(MongoTemplate.java:1747)