如何使用Java从集合中删除多个文档？
在Java中，com.mongodb.client.MongoCollection接口提供了方法deleteMany()。使用此方法，您可以一次从集合中删除多个文档，为此，您需要通过指定删除条件的过滤器。
示例
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 org.bson.conversions.Bson;
import com.mongodb.MongoClient;
public class DeletingMultipleDocuments {
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", "Delhi");
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", 45).append("city", "Delhi");
Document document5 = new Document("name", "Sarmista").append("age", 35).append("city", "Mumbai");
//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");
System.out.println("集合的内容：");
FindIterable<Document> iterDoc = collection.find();
int i = 1;
System.out.println("剩余文件：");
Iterator it = iterDoc.iterator();
while (it.hasNext()) {
System.out.println(it.next());
i++;
}
collection = database.getCollection("students");
//删除多个文档
Bson filter = new Document("city", "Delhi");
collection.deleteMany(filter);
System.out.println("Document deleted successfully...");
//删除操作后检索文档
iterDoc = collection.find();
System.out.println("剩余文件：");
it = iterDoc.iterator();
while (it.hasNext()) {
System.out.println(it.next());
i++;
}
}
}输出结果
Documents Inserted
集合的内容：
剩余文件：
Document{{_id=5e896b042e4a2f3badebddae, name=Ram, age=26, city=Delhi}}
Document{{_id=5e896b042e4a2f3badebddaf, name=Robert, age=27, city=Vishakhapatnam}}
Document{{_id=5e896b042e4a2f3badebddb0, name=Rhim, age=30, city=Delhi}}
Document{{_id=5e896b042e4a2f3badebddb1, name=Radha, age=45, city=Delhi}}
Document{{_id=5e896b042e4a2f3badebddb2, name=Sarmista, age=35, city=Mumbai}}
Document deleted successfully...
剩余文件：
Document{{_id=5e896b042e4a2f3badebddaf, name=Robert, age=27, city=Vishakhapatnam}}
Document{{_id=5e896b042e4a2f3badebddb2, name=Sarmista, age=35, city=Mumbai}}