Question

基于https://jira.mongodb.org/browse/JAVA-1741我正在尝试实现和使用TimestampCodec，并期望在读取MongoCollection时使用decode（），但由于某种原因，decode（）不是执行，因此数据库中的IsoDate值转换为java.util.Date而不是预期的java.sql.Timestamp。

在检索MongoCollection时使用TimestampCodec.decode（）的正确方法是什么？

我有以下内容，但它失败了 java.lang.AssertionError：expected：＆lt; class [Ljava.sql.Timestamp;＆gt;但是：＆lt; class java.util.Date＆gt;

@Test
public void testTimestamp() {
    Map<BsonType, Class<?>> replacements = new HashMap<BsonType, Class<?>>();
    replacements.put(BsonType.DATE_TIME, Timestamp.class);
    BsonTypeClassMap bsonTypeClassMap = new BsonTypeClassMap(replacements);
    DocumentCodecProvider documentCodecProvider =
            new DocumentCodecProvider(bsonTypeClassMap);
    CodecRegistry codecRegistry = CodecRegistries.fromRegistries(
    CodecRegistries.fromCodecs(
            new TimestampCodec()),
            MongoClient.getDefaultCodecRegistry(),
            CodecRegistries.fromProviders(documentCodecProvider));
    Builder optionsBuilder = new MongoClientOptions.Builder();
    optionsBuilder.codecRegistry(MongoCodecs.codecRegistry());
    MongoClientOptions options = optionsBuilder.build();
    MongoClient mongo = new MongoClient(new ServerAddress(), options);
    MongoDatabase db = mongo.getDatabase("mydb");
    MongoCollection<Document> collection = db.getCollection("test");
    try {
        collection.insertOne(new Document("date", new Timestamp(new Date().getTime())));
        assertEquals(Timestamp[].class, collection.find().first().get("date").getClass());
    } finally {
        collection.drop();
        mongo.close();
    }
}

Answer 1

除了轻微的错误，解决方案是改变编解码器注册表的顺序，以便MongoClient.getDefaultCodecRegistry（）是最后一个。

正确的代码是：

@Test
public void testTimestamp() {
    Map<BsonType, Class<?>> replacements = new HashMap<BsonType, Class<?>>();
    replacements.put(BsonType.DATE_TIME, Timestamp.class);
    BsonTypeClassMap bsonTypeClassMap = new BsonTypeClassMap(replacements);
    DocumentCodecProvider documentCodecProvider =
            new DocumentCodecProvider(bsonTypeClassMap);
    CodecRegistry codecRegistry = CodecRegistries.fromRegistries(
            CodecRegistries.fromCodecs(
                    new TimestampCodec()),
            CodecRegistries.fromProviders(documentCodecProvider),
            MongoClient.getDefaultCodecRegistry());
    Builder optionsBuilder = new MongoClientOptions.Builder();
    optionsBuilder.codecRegistry(codecRegistry);
    MongoClientOptions options = optionsBuilder.build();
    MongoClient mongo = new MongoClient(new ServerAddress(), options);
    MongoDatabase db = mongo.getDatabase("mydb");
    MongoCollection<Document> collection = db.getCollection("test");
    try {
        collection.insertOne(new Document("date", new Timestamp(new Date().getTime())));
        assertEquals(Timestamp.class, collection.find().first().get("date").getClass());
    } finally {
        collection.drop();
        mongo.close();
    }
}

如何使MongoCollectoin返回java.sql.Timestamp？

1 个答案: