如何使用Java对MongoDB集合的文档进行排序？
从MongoDB集合中检索记录时，可以使用sort()方法对结果中的记录进行排序。
语法
db.COLLECTION_NAME.find().sort({KEY:1})JavaMongoDB库提供了一个具有相同名称的方法，以find()通过传递排序类型（升序或降序）和所需的字段名称来限制调用此方法（在该方法的结果上）的记录数将记录排序为-
sort(Sorts.ascending("age");示例
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Sorts;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.bson.Document;
import com.mongodb.MongoClient;
public class SortingRecords {
public static void main( String args[] ) {
//创建一个MongoDB客户端
MongoClient mongo = new MongoClient( "localhost" , 27017 );
//连接到数据库
MongoDatabase database = mongo.getDatabase("myDatabase");
//创建一个收集对象
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");
//插入创建的文档
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");
//检索集合对象
collection = database.getCollection("students");
//检索文档有限制
FindIterable<Document> iterDoc =
collection.find().sort(Sorts.ascending("age"));
Iterator it = iterDoc.iterator();
while (it.hasNext()) {
System.out.println(it.next());
}
}
}输出结果
Documents Inserted
Document{{_id=5e88843d5c851b345fce2a33, name=Ram, age=26, city=Hyderabad}}
Document{{_id=5e88843d5c851b345fce2a34, name=Robert, age=27, city=Vishakhapatnam}}
Document{{_id=5e88843d5c851b345fce2a36, name=Radha, age=28, city=Mumbai}}
Document{{_id=5e88843d5c851b345fce2a35, name=Rhim, age=30, city=Delhi}}
Document{{_id=5e88843d5c851b345fce2a37, name=Ramani, age=45, city=Pune}}