MongoDB 实验——java 和 MongoDB 第2关：Java 操作 MongoDB 数据库（二）

package step2;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.ArrayList;
import java.util.List;
import java.util.function.Consumer;
import org.bson.Document;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.FindIterable;
import com.mongodb.Block;  
import com.mongodb.client.model.Filters;
import com.mongodb.client.MongoCursor;
public class Mongo{
    public static void main( String args[] ){
        Logger log = Logger.getLogger("org.mongodb.driver");  
        log.setLevel(Level.OFF);          //屏蔽带时间的输出
        try{ 
            //仿照第一关，连接数据库mydb2并选择集合test2
            /********* Begin *********/ 
            MongoClient mongoClient =new MongoClient("localhost");
            MongoDatabase mongoDatabase = mongoClient.getDatabase("mydb2");
            MongoCollection collection =mongoDatabase.getCollection("test2");
            //在下面补充代码，插入文档到集合test2中
            /********* Begin *********/ 
            Document document1=new Document();  
         document1.append("_id","1");  
         document1.append("name","Xiaoming");  
         document1.append("sex","man");  
         document1.append("age",21);
         Document document2=new Document();  
         document2.append("_id","2");  
         document2.append("name","Xiaohong");  
         document2.append("sex","woman");  
         document2.append("age",20);
         Document document3=new Document();      
         document3.append("_id","3");  
         document3.append("name","Xiaoliang");  
         document3.append("sex","man");  
         document3.append("age",22);  
         List documents =new ArrayList();  
         documents.add(document1);  
         documents.add(document2);  
         documents.add(document3);  
         collection.insertMany(documents);  
            /********* End *********/
            //在Begin和End之间补充代码，请勿修改代码的原本框架
            FindIterable<Document> iter = collection.find();
            System.out.println("文档插入结果如下：");
            iter.forEach(new Block<Document>() {
              public void apply(Document _doc) {
                System.out.println(_doc.toJson());
              }
            });
            //在下面补充代码，更新 Xiaohong 的信息为23岁
            /********* Begin *********/ 
            collection.updateMany(Filters.eq("name", "Xiaohong"),new Document("$set",new Document("age",23)));
            /********* End *********/
            //在Begin和End之间补充代码，请勿修改代码的原本框架
            FindIterable<Document> findIterable = collection.find();  
            MongoCursor<Document> mongoCursor = findIterable.iterator(); 
            System.out.println("更新后文档内容如下：");
            while(mongoCursor.hasNext()){  
            System.out.println(mongoCursor.next());  
            };
            //在下面补充代码，删除Xiaoliang的信息
            /********* Begin *********/ 
            collection.deleteMany(Filters.eq("name","Xiaoliang"));  
            /********* End *********/ 
            //在Begin和End之间补充代码，请勿修改代码的原本框架
            FindIterable<Document> iter1 = collection.find();
            System.out.println("删除信息后的文档内容为：");
            
            iter1.forEach(new Consumer<Document>() {
                @Override
                public void accept(Document document) {
                    System.out.println(document.toJson());
                }
            });

            collection.drop();
        }catch (Exception e) {
            System.err.println( e.getClass().getName() + ": " + e.getMessage() );
        }
    }
}