Mongo 为 NumberLong、Timestamp 等结构提供了扩展的 JSON 语法，可在 Mongo shell 上运行。为了使其在 Java 代码中工作，它们具有严格的 JSON 模式，其中这些运算符使用 JSON (https://docs.mongodb.com/manual/reference/mongodb-extended-json/#bson-data-types-and-associated-representations) 表示。要使用 Java 执行此操作，您可以创建一个自定义转换器并将其注册到您的 MappingMongoConverter（请参阅下面的 sn-p）。转换器应将数据类型（例如 BSONTimestamp）转换为适当的严格 JSON 文档格式。
@WritingConverter
public class BsonTimestampToDocumentConverter implements Converter<BSONTimestamp, Document> {
private static final Logger LOGGER = LoggerFactory.getLogger(BsonTimestampToDocumentConverter.class);
public BsonTimestampToDocumentConverter() {
//
}
@Override
public Document convert(BSONTimestamp source) {
LOGGER.trace(">>>> Converting BSONTimestamp to Document");
Document value = new Document();
value.put("t", source.getTime());
value.put("i", source.getInc());
return new Document("$timestamp", value);
}
}
像这样在 MappingMongoConverter 中注册
public MappingMongoConverter syncLocalMappingMongoConverter() throws Exception {
MongoMappingContext mappingContext = new MongoMappingContext();
DbRefResolver dbRefResolver = new DefaultDbRefResolver(syncLocalDbFactory());
MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mappingContext);
converter.setCustomConversions(customConversions());
return converter;
}
private CustomConversions customConversions() {
List<Converter<?, ?>> converterList = new ArrayList<>();
converterList.add(new BsonTimestampToDocumentConverter());
// add the other converters here
return new CustomConversions(CustomConversions.StoreConversions.NONE, converterList);
}
这是一个示例，我使用它查询 oplog 存储库以在特定时间后返回记录（存储库中的 Sync 用于将其与我正在处理的反应性异步内容区分开来。Async 存储库看起来完全相同，除了它应该扩展 ReactiveMongoRepository)。 OplogRecord 类是我创建的一个 Java bean，用于匹配 MongoDb oplog 记录的结构。
public interface SyncOplogRepository extends MongoRepository<OplogRecord, Long> {
@Query(value = "{ \"op\": { $nin: ['n', 'c'] } }") List<OplogRecord> findRecordsNotEqualToNOrC();
@Query(value = "{'ts' : {$gte : ?0}, \"op\": { $nin: ['n', 'c'] } }")
List<OplogRecord> findRecordsNotEqualToNOrCAfterTime(BSONTimestamp timestamp);
@Query(value = "{'ts' : {$lt : ?0}, \"op\": { $nin: ['n', 'c'] } }")
List<OplogRecord> findRecordsNotEqualToNOrCBeforeTime(BSONTimestamp timestamp);
}
OplogRecord 类
import com.mongodb.DBObject;
import org.bson.BsonTimestamp;
import org.bson.types.BSONTimestamp;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
import java.util.Map;
@Document(collection = "oplog.rs")
public class OplogRecord {
@Id
private Long id;
/**
* Timestamp
*/
private BsonTimestamp ts;
/**
* Unique id for this entry
*/
private Long h;
/**
* DB and collection name of change.
*/
private String ns;
/**
* The actual document that was modified/inserted/deleted
*/
private Map<String, Object> o;
/**
* The operation that was performed
*/
private String op;
/**
* ??
*/
private Long t;
/**
* ??
*/
private Integer v;
public BsonTimestamp getTs() {
return ts;
}
public void setTs(BsonTimestamp ts) {
this.ts = ts;
}
public Long getH() {
return h;
}
public void setH(Long h) {
this.h = h;
}
public String getNs() {
return ns;
}
public void setNs(String ns) {
this.ns = ns;
}
public Map<String, Object> getO() {
return o;
}
public void setO(Map<String, Object> o) {
this.o = o;
}
public String getOp() {
return op;
}
public void setOp(String op) {
this.op = op;
}
public Long getT() {
return t;
}
public void setT(Long t) {
this.t = t;
}
public Integer getV() {
return v;
}
public void setV(Integer v) {
this.v = v;
}
}
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