java - 格式化 MongoDB 时间戳

Question

我的时间戳位于 MongoDB 中数据库，我想以可读的日期格式漂亮地打印它们。使用Java和 MongoClient我有以下代码:

import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;

import java.sql.Timestamp;

public class MongoDBTest
{
    public static void main(String[] arguments)
    {
        MongoClient client = new MongoClient("127.0.0.1", 27017);
        String databaseName = "my_database";
        MongoDatabase database = client.getDatabase(databaseName);
        String collectionName = "my_collection";
        MongoCollection collection = database.getCollection(collectionName);

        try (MongoCursor<Document> cursor = collection.find().iterator())
        {
            while (cursor.hasNext())
            {
                String json = cursor.next().toJson();
                Document document = Document.parse(json);
                String stringTimestamp = document.get("timestamp").toString();
                Timestamp timestamp = new Timestamp(Long.parseLong(stringTimestamp));
                System.out.println("Timestamp: " + stringTimestamp + " Formatted: " + timestamp);
            }
        }
    }
}

打印的时间戳似乎不正确，因为它们都来自 1970但不应该是:

Timestamp: 1357466440 Formatted: 1970-01-16 18:04:26.44
Timestamp: 1357466449 Formatted: 1970-01-16 18:04:26.449
Timestamp: 1357466457 Formatted: 1970-01-16 18:04:26.457
Timestamp: 1357466462 Formatted: 1970-01-16 18:04:26.462
Timestamp: 1357466469 Formatted: 1970-01-16 18:04:26.469
Timestamp: 1357466469 Formatted: 1970-01-16 18:04:26.469
Timestamp: 1357466477 Formatted: 1970-01-16 18:04:26.477
Timestamp: 1357466477 Formatted: 1970-01-16 18:04:26.477

如何获取“真实”格式化日期？

Answer 1

看起来您有以秒为单位的时间戳值。乘以 1000 即可得到毫秒单位。

 String stringTimestamp = document.get("timestamp").toString();
 Timestamp timestamp = new Timestamp(Long.parseLong(stringTimestamp) * 1000);
 Instant instant = timestamp.toInstant();

从这里您可以使用DateTimeFormatter进行格式化。根据您的需要，您还可以更改为 LocalDateTime