MongoTemplate 标准查询

Question

I'm generating a complicated Mongo query depending on multiple parameters. One of criterion that I want to make with Criteria helper class is:

{"field1": {$exists: true, $ne: false}}

I tried to make it with:

Criteria.where("field1").is(Criteria.where("$ne").is(false).and("$exists").is(true))

But it generates:

{ "field1" : { $java : org.springframework.data.mongodb.core.query.Criteria@23864e60 } 

So, how to achieve the exact query that i need? I can't hardcode that query string, because these type criterions are generated dynamically for field1,...fieldN and then combined with $or :

statusCriteria = statusCriteria.orOperator(criterias.toArray(new Criteria[criterias.size()]));

Answer 1

Since you can't use Criteria.and() to add multiple criteria into the same field, use Criteria.andOperator() as follows:

Query query = new Query();
query.addCriteria(
    new Criteria().andOperator(
        Criteria.where("field1").exists(true),
        Criteria.where("field1").ne(false)
    )
);

List<Foo> result = mongoTemplate.find(query, Foo.class);
System.out.println("query - " + query.toString());

for (Foo foo : result) {
    System.out.println("result - " + foo);
}

Answer 2

Query query = new Query(Criteria.where("field1").exists(true).ne(false));

或者，如果field1在出现时总是一个布尔值：

Query query = new Query(Criteria.where("field1").is(true));

Answer 3

@Document(collection="student")
public class Student {
    private String id;
    private String name;
    private List<String> subjects;
}

search a subject for list for student who have taken that subject.

@Query("{'subjects':{$elemMatch:{$in:?0}}}")
public List<Student> getDrugByBrand(String[] subjects);

above is working but i want to create the query criteria.

can any one convert {'subjects':{$elemMatch:{$in:?0}}} in to criteria

i am trying like this but its not working

if(subject != null && ! subject()){
    criteria.add(Criteria.where("subjects")
            .elemMatch(Criteria.where("--what to put here for index--")
            .regex(subject,"i")
    ));
}