我正在遍历键/值对列表并对每个键/值执行find。我可以在sql中创建一个单独的查询文档,以便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,
答案 0 :(得分:4)
您可以重构代码以创建$or
表达式。无需明确$and
运算符。
像
这样的东西 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);
这应输出类似
的查询{ "$or" : [{ "key1" : "value1", "key2" : "value2" }, { "key3" : "value3", "key4" : "value4" }] }
答案 1 :(得分:2)
如果你想用下面的值查询多个字段(field1, field2, ....) 是解决方案
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