无涯教程-MongoDB - Java - IPS99技术分享

标签：Java database MongoDB successfully 无涯 client mongodb import com

在本章中，无涯教程将学习如何设置MongoDB JDBC驱动程序。

安装驱动

在Java程序中开始使用MongoDB之前，需要确保在计算机上设置了MongoDB JDBC驱动程序和Java，您可以检查Java教程以在计算机上安装Java。现在，让无涯教程检查如何设置MongoDB JDBC驱动程序。

您需要从路径下载 jar mongo.jar。确保下载它的最新版本。
您需要将mongo.jar包含到您的类路径中。

连接数据库

要连接数据库，您需要指定数据库名称，如果数据库不存在，则MongoDB会自动创建它。

以下是连接到数据库的代码片段-

import com.mongodb.client.MongoDatabase; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class ConnectToDB { 
   
   public static void main( String args[] ) {  
      
      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 
   
      //创建凭证
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb"); 
      System.out.println("Credentials ::"+ credential);     
   } 
}

现在，让无涯教程编译并运行上述程序以创建无涯教程的数据库myDb，如下所示。

$javac ConnectToDB.java 
$java ConnectToDB

执行后，上述程序将为您提供以下输出。

Connected to the database successfully 
Credentials ::MongoCredential{
   mechanism=null, 
   userName='sampleUser', 
   source='myDb', 
   password=<hidden>, 
   mechanismProperties={}
}

创建集合

要创建集合，请使用 com.mongodb.client.MongoDatabase 类的 createCollection()方法。

以下是创建集合的代码片段-

import com.mongodb.client.MongoDatabase; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class CreatingCollection { 
   
   public static void main( String args[] ) {  
      
      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 
     
      //创建凭证
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb");  
      
      //创建集合
      database.createCollection("sampleCollection"); 
      System.out.println("Collection created successfully"); 
   } 
}

在编译时，上述程序为您提供以下输出-

Connected to the database successfully 
Collection created successfully

获取/选择集合

要从数据库中获取/选择集合，请使用 com.mongodb.client.MongoDatabase 类的 getCollection()方法。

import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase; 

import org.bson.Document; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class selectingCollection { 
   
   public static void main( String args[] ) {  
      
      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 
     
      //创建凭证
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb");  
      
      //创建集合
      System.out.println("Collection created successfully"); 

      //检索集合
      MongoCollection<Document> collection = database.getCollection("myCollection"); 
      System.out.println("Collection myCollection selected successfully"); 
   }
}

在编译时，上述程序为您提供以下输出-

Connected to the database successfully 
Collection created successfully 
Collection myCollection selected successfully

插入数据

要将文档插入MongoDB，请使用 com.mongodb.client.MongoCollection 类的 insert()方法。

import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase; 

import org.bson.Document;  
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class InsertingDocument { 
   
   public static void main( String args[] ) {  
      
      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 

      //创建凭证
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb"); 

      //检索集合
      MongoCollection<Document> collection = database.getCollection("sampleCollection"); 
      System.out.println("Collection sampleCollection selected successfully");

      Document document = new Document("title", "MongoDB") 
      .append("id", 1)
      .append("description", "database") 
      .append("likes", 100) 
      .append("url", "http://www.learnfk.com/mongodb/") 
      .append("by", "Learnfk point");  
      collection.insertOne(document); 
      System.out.println("Document inserted successfully");     
   } 
}

在编译时，上述程序为您提供以下输出-

Connected to the database successfully 
Collection sampleCollection selected successfully 
Document inserted successfully

检索数据

要从集合中选择所有文档，请使用 com.mongodb.client.MongoCollection 类的 find()方法，此方法返回一个游标，因此您需要迭代此游标。

import com.mongodb.client.FindIterable; 
import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase;  

import java.util.Iterator; 
import org.bson.Document; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class RetrievingAllDocuments { 
   
   public static void main( String args[] ) {  
      
      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 

      //创建凭证
      MongoCredential credential;
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb");  
      
      //检索集合
      MongoCollection<Document> collection = database.getCollection("sampleCollection");
      System.out.println("Collection sampleCollection selected successfully"); 

      //获取可迭代对象
      FindIterable<Document> iterDoc = collection.find(); 
      int i = 1; 

      //获取迭代器
      Iterator it = iterDoc.iterator(); 
    
      while (it.hasNext()) {  
         System.out.println(it.next());  
      i++; 
      }
   } 
}

在编译时，上述程序为您提供以下输出-

Document{{
   _id=5967745223993a32646baab8, 
   title=MongoDB, 
   id=1, 
   description=database, 
   likes=100, 
   url=http://www.learnfk.com/mongodb/, by=Learnfk point
}}  
Document{{
   _id=7452239959673a32646baab8, 
   title=RethinkDB, 
   id=2, 
   description=database, 
   likes=200, 
   url=http://www.learnfk.com/rethinkdb/, by=Learnfk point
}}

更新数据

要从集合中更新文档，请使用 com.mongodb.client.MongoCollection 类的 updateOne()方法。

import com.mongodb.client.FindIterable; 
import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase; 
import com.mongodb.client.model.Filters; 
import com.mongodb.client.model.Updates; 

import java.util.Iterator; 
import org.bson.Document;  
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class UpdatingDocuments { 
   
   public static void main( String args[] ) {  
      
      //获取迭代器
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 
     
      //创建 Mongo 客户端
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb"); 

      //检索集合
      MongoCollection<Document> collection = database.getCollection("sampleCollection");
      System.out.println("Collection myCollection selected successfully"); 

      collection.updateOne(Filters.eq("id", 1), Updates.set("likes", 150));       
      System.out.println("Document update successfully...");  
      
      //更新后检索文件
      //获取可迭代对象
      FindIterable<Document> iterDoc = collection.find(); 
      int i = 1; 

      //获取迭代器
      Iterator it = iterDoc.iterator(); 

      while (it.hasNext()) {  
         System.out.println(it.next());  
         i++; 
      }     
   }  
}

在编译时，上述程序为您提供以下输出-

Document update successfully... 
Document {{
   _id=5967745223993a32646baab8, 
   title=MongoDB, 
   id=1, 
   description=database, 
   likes=150, 
   url=http://www.learnfk.com/mongodb/, by=Learnfk point
}}

删除数据

要从集合中删除文档，您需要使用 com.mongodb.client.MongoCollection 类的 deleteOne()方法。

import com.mongodb.client.FindIterable; 
import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase; 
import com.mongodb.client.model.Filters;  

import java.util.Iterator; 
import org.bson.Document; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class DeletingDocuments { 
   
   public static void main( String args[] ) {  
   
      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 );
      
      //创建凭证
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb"); 

      //检索集合
      MongoCollection<Document> collection = database.getCollection("sampleCollection");
      System.out.println("Collection sampleCollection selected successfully"); 

      //删除文件
      collection.deleteOne(Filters.eq("id", 1)); 
      System.out.println("Document deleted successfully...");  
      
      //更新后检索文件
      //获取可迭代对象
      FindIterable<Document> iterDoc = collection.find(); 
      int i = 1; 

      //获取迭代器
      Iterator it = iterDoc.iterator(); 

      while (it.hasNext()) {  
         System.out.println("Inserted Document: "+i);  
         System.out.println(it.next());  
         i++; 
      }       
   } 
}

在编译时，上述程序为您提供以下输出-

Connected to the database successfully 
Collection sampleCollection selected successfully 
Document deleted successfully...

删除集合

要从数据库中删除集合，您需要使用 com.mongodb.client.MongoCollection 类的 drop()方法。

import com.mongodb.client.MongoCollection; 
import com.mongodb.client.MongoDatabase;  

import org.bson.Document;  
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class DropingCollection { 
   
   public static void main( String args[] ) {  

      //创建 Mongo 客户端
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 

      //创建凭证
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 
      System.out.println("Connected to the database successfully");  
      
      //访问数据库
      MongoDatabase database = mongo.getDatabase("myDb");  
      
      //创建集合
      System.out.println("Collections created successfully"); 

      //检索集合
      MongoCollection<Document> collection = database.getCollection("sampleCollection");

      collection.drop(); 
      System.out.println("Collection dropped successfully");
   } 
}

在编译时，上述程序为您提供以下输出-

Connected to the database successfully 
Collection sampleCollection selected successfully 
Collection dropped successfully

列出所有集合

要列出数据库中的所有集合，您需要使用 com.mongodb.client.MongoDatabase 类的 listCollectionNames()方法。

import com.mongodb.client.MongoDatabase; 
import com.mongodb.MongoClient; 
import com.mongodb.MongoCredential;  

public class ListOfCollection { 
   
   public static void main( String args[] ) {  
      
      //检索集合
      MongoClient mongo = new MongoClient( "localhost" , 27017 ); 

      //创建Mongo客户
      MongoCredential credential; 
      credential = MongoCredential.createCredential("sampleUser", "myDb", 
         "password".toCharArray()); 

      System.out.println("Connected to the database successfully");  
      
      //创建凭据
      MongoDatabase database = mongo.getDatabase("myDb"); 
      System.out.println("Collection created successfully"); 
      for (String name : database.listCollectionNames()) { 
         System.out.println(name); 
      } 
   }
}

在编译时，上述程序为您提供以下输出-

Connected to the database successfully 
Collection created successfully 
myCollection 
myCollection1 
myCollection5

其余的MongoDB方法 save()，limit()，skip()，sort()等的工作方式与后续教程中说明的相同。

参考链接

https://www.learnfk.com/mongodb/mongodb-java.html

标签：Java,database,MongoDB,successfully,无涯,client,mongodb,import,com
From： https://blog.51cto.com/u_14033984/8181479

无涯教程-MongoDB - Java

安装驱动

连接数据库

创建集合

获取/选择集合

插入数据

检索数据

更新数据

删除数据

删除集合

列出所有集合

参考链接

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