1：创建字段索引

collection 是集合名称，keys 是一个包含一个或多个字段名，options是排序方向，1正序，-1倒叙

db.collection.createIndex(keys, options)

#单字段
db.collection.createIndex(name: 1)

#多字段
db.collection.createIndex{name: 1, age: -1}

2：mongodb批量修改

BulkOperations bulkOperations = mongoTemplate.bulkOps(BulkMode.UNORDERED, RealtimeEntity.class);updateList.forEach(realtimeEntity -> {Query query = new Query(Criteria.where("pn").is(realtimeEntity.getPn()));Update update = new Update().set("pnVal", realtimeEntity.getPnVal()).set("tm", realtimeEntity.getTm()).set("rm", realtimeEntity.getRm());bulkOperations.updateOne(query, update);
});
bulkOperations.execute();

注意：必须创建索引这样更新的效率快