在Spring Mongo DB查询中指定多个条件

Question

我正在遍历键/值对的列表，并对每个键/值执行查找。我可以创建一个单一的查询文档以在sql中实现联合吗，这样就只有一个数据库调用。

    List<User> userList = new ArrayList<User>();
    for (Map accounts:attributes) {
        Query query = new Query();
        List<Criteria> andCriteriaList = new ArrayList<Criteria>();
        accounts.forEach((key, value) -> {
            Criteria criteria = Criteria.where((String) key).is(value);
            andCriteriaList.add(criteria);
        });
        query.addCriteria(new Criteria().andOperator(andCriteriaList.toArray(new Criteria[andCriteriaList.size()])));
        if (mongoTemplate.exists(query, User.class)) {
            userList.add((User)mongoTemplate.find(query, User.class));
            //System.out.println(mongoTemplate.find(query, User.class));
        }

谢谢，

Answer 1

如果您想查询具有以下值的多个字段（field1，field2，...），则解决方案

Query query = new Query();
List<Criteria> criteria = new ArrayList<>();

criteria.add(Criteria.where(field1).is(field1val));
criteria.add(Criteria.where(field2).is(field2val));
// you can add all your fields here as above

query.addCriteria(new Criteria().andOperator(criteria.toArray(new Criteria[criteria.size()])));
List<JSONObject> filteredVals = mongoOperations.find(query, JSONObject.class);

上面返回的filteredVals是JSONObject

Answer 2

您可以重构代码以创建$or表达式。无需显式$and运算符。

就像是

 Query orQuery = new Query();
 Criteria orCriteria = new Criteria();
 List<Criteria> orExpression =  new ArrayList<>();
 for (Map<String, Object> accounts : attributes) {
   Criteria expression = new Criteria();
   accounts.forEach((key, value) -> expression.and(key).is(value));
   orExpression.add(expression);
 }
 orQuery.addCriteria(orCriteria.orOperator(orExpression.toArray(new Criteria[orExpression.size()])));
 List<User> userList = mongoOperations.find(orQuery, User.class);

这应该输出查询像

{ "$or" : [{ "key1" : "value1", "key2" : "value2" }, { "key3" : "value3", "key4" : "value4" }] }