最近使用mongodb實現一個需求，需要批量處理資料，並且存在則修改，不存在則新增，updateMany方法，無法達到要求，經查，發現mongodb中存在一個BulkWrite方法可以實現該需求

使用如下命令建立用於測試的db和collection以及新增index並檢視

use mockdb
db.mockcoll.createIndex({"flag":1})
db.mockcoll.getIndexes()

mockcoll中只存在一個欄位flag，並在該欄位建立唯一索引

下面為程式碼示例

public interface MongoCons {

    String mockdbName 
 
= "mockdb";
    String mockcollName = "mockcoll";
    
    static MongoCollection<Document> getCollection(MongoTemplate mongoTemplate){
        MongoDatabase mongoDatabase = mongoTemplate.getMongoDbFactory().getMongoDatabase(mockdbName);
        MongoCollection<Document> collection = mongoDatabase.getCollection(mockcollName);
        
 
return collection;
    }
    
}

@Component
public class MongoBulkDao {

    private Logger logger = LoggerFactory.getLogger(MongoBulkDao.class);
    @Autowired
    private MongoTemplate mongoTemplate;

    public void addOrUpdate(List<String> dataList) {
        try {
            MongoCollection
 
<Document> collection = MongoCons.getCollection(mongoTemplate);

            List<WriteModel<Document>> list = new ArrayList<>();

            Iterator<String> iterator = dataList.iterator();
            String next = null;
            while (iterator.hasNext()) {
                next = iterator.next();
                BasicDBObject filter = new BasicDBObject().append("flag", next);
                BasicDBObject update = new BasicDBObject().append("$set", new BasicDBObject().append("flag", next));

                UpdateOneModel<Document> um = new UpdateOneModel<Document>(filter, update,
                        new UpdateOptions().upsert(true));
                list.add(um);
                iterator.remove();
            }

            collection.bulkWrite(list, new BulkWriteOptions().ordered(false));
        } catch (Exception e) {
            logger.error("",e);
        }
    }