使用 java 从 MongoDB 中检索数据时如何跳过文档?
从 MongoDB 集合中检索记录时,可以使用 skip() 方法跳过结果中的记录。
语法
db.COLLECTION_NAME.find().limit(NUMBER).skip(NUMBER)
Java MongoDB 库提供了一个同名方法,用于跳过记录,调用此方法(在 find() 方法的结果上)绕过一个表示要跳过的记录数量的整数值。
范例
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.bson.Document;
import com.mongodb.MongoClient;
public class SkipRecords {
public static void main( String args[] ) {
//Creating a MongoDB client
MongoClient mongo = new MongoClient( "localhost" , 27017 );
//Connecting to the database
MongoDatabase database = mongo.getDatabase("myDatabase");
//Creating a collection object
MongoCollection<Document>collection = database.getCollection("students");
Document document1 = new Document("name", "Ram").append("age", 26).append("city", "Hyderabad");
Document document2 = new Document("name", "Robert").append("age", 27).append("city", "Vishakhapatnam");
Document document3 = new Document("name", "Rhim").append("age", 30).append("city", "Delhi");
Document document4 = new Document("name", "Radha").append("age", 28).append("city", "Mumbai");
Document document5 = new Document("name", "Ramani").append("age", 45).append("city", "Pune");
//Inserting the created documents
List<Document> list = new ArrayList<Document>();
list.add(document1);
list.add(document2);
list.add(document3);
list.add(document4);
list.add(document5);
collection.insertMany(list);
System.out.println("Documents Inserted");
//Retrieving a collection object
collection = database.getCollection("students");
//Retrieving the documents with a limit
FindIterable<Document> iterDoc = collection.find().skip(2);
Iterator it = iterDoc.iterator();
while (it.hasNext()) {
System.out.println(it.next());
}
}
}输出
Documents Inserted
Documents Inserted
Document{{_id=5e8886f97631225872d13217, name=Rhim, age=30, city=Delhi}}
Document{{_id=5e8886f97631225872d13218, name=Radha, age=28, city=Mumbai}}
Document{{_id=5e8886f97631225872d13219, name=Ramani, age=45, city=Pune}}
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