一、錯誤描述

                   在專案中使用java連線mongodb資料庫，使用的是mongoclient連線，程式碼如下：

public  void mongodbTest (String ip,int port,String user,String password,String dbname){
		  MongoDatabase db=null;
		  MongoClient client=null;
		  try{
		     MongoClientOptions.Builder build = new MongoClientOptions.Builder();  
		        //與資料最大連線數50  
		        build.connectionsPerHost(50);  
		        //如果當前所有的connection都在使用中，則每個connection上可以有50個執行緒排隊等待  
		        build.threadsAllowedToBlockForConnectionMultiplier(50);  
		        build.connectTimeout(1*60*1000);  
		        build.maxWaitTime(2*60*1000);  
		        MongoClientOptions options = build.build();	
                         //設定伺服器資訊	        
		        ServerAddress serverAddress = new ServerAddress(ip, port);  
	                List<ServerAddress> seeds = new ArrayList<ServerAddress>();  
	                seeds.add(serverAddress);  
                         //設定驗證資訊
	                MongoCredential credentials = MongoCredential.createMongoCRCredential(user, dbname,  
	            		password.toCharArray());  
	                List<MongoCredential> credentialsList = new ArrayList<MongoCredential>();  
	                credentialsList.add(credential); 	            
		        client =new MongoClient(seeds, credentialsList,options);  
		        //獲取資料庫mydb,不存在的話，會自動建立該資料庫  
		        db = client.getDatabase("mydb");  
		       
		  }catch (Exception e) {  
		       return e.getClass().getName() + ": " + e.getMessage();	          
	            
		  }
		      if(db!=null&&client!=null){
                            //獲取集合
                           MongoCollection<Document> documents = db.getCollection("mydb");  		       
                            Document document=documents.find().first();   
                            System.out.println(document.toJson());
                        
		      }
		     client.close();                
	}
 

com.mongodb.MongoSecurityException: Exception authenticating
	at com.mongodb.connection.NativeAuthenticator.authenticate(NativeAuthenticator.java:48)
	at com.mongodb.connection.InternalStreamConnectionInitializer.authenticateAll(InternalStreamConnectionInitializer.java:109)
	at com.mongodb.connection.InternalStreamConnectionInitializer.initialize(InternalStreamConnectionInitializer.java:46)
	at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:116)
	at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:113)
	at java.lang.Thread.run(Unknown Source)
Caused by: com.mongodb.MongoCommandException: Command failed with error 18: 'auth failed' on server xxx.xxx.xxx.xxx:27017. The full response is { "ok" : 0.0, "errmsg" : "auth failed", "code" : 18 }
 

	at com.mongodb.connection.CommandHelper.createCommandFailureException(CommandHelper.java:170)
	at com.mongodb.connection.CommandHelper.receiveCommandResult(CommandHelper.java:123)
	at com.mongodb.connection.CommandHelper.executeCommand(CommandHelper.java:32)
	at com.mongodb.connection.NativeAuthenticator.authenticate(NativeAuthenticator.java:46)
	... 5 more
 

    二、解決辦法

                官網查了一下官網API，找到了問題的所在，文件如下

         到mongodb資料庫的admin資料庫中一查，發現驗證機制為SCRAM-SHA-1，於是在java程式碼中將createMongoCRCredential()方法換成createScramShalCredential()方法，驗證通過，成功解決問題

public  void mongodbTest (String ip,int port,String user,String password,String dbname){
		  MongoDatabase db=null;
		  MongoClient client=null;
		  try{
		     MongoClientOptions.Builder build = new MongoClientOptions.Builder();  
		        //與資料最大連線數50  
		        build.connectionsPerHost(50);  
		        //如果當前所有的connection都在使用中，則每個connection上可以有50個執行緒排隊等待  
		        build.threadsAllowedToBlockForConnectionMultiplier(50);  
		        build.connectTimeout(1*60*1000);  
		        build.maxWaitTime(2*60*1000);  
		        MongoClientOptions options = build.build();	
                         //設定伺服器資訊	        
		        ServerAddress serverAddress = new ServerAddress(ip, port);  
	                List<ServerAddress> seeds = new ArrayList<ServerAddress>();  
	                seeds.add(serverAddress);  
                         //設定驗證資訊
	                MongoCredential credentials = MongoCredential.createScramSha1Credential(user, dbname, password.toCharArray());  

	                List<MongoCredential> credentialsList = new ArrayList<MongoCredential>();  
	                credentialsList.add(credential); 	            
		        client =new MongoClient(seeds, credentialsList,options);  
		        //獲取資料庫mydb,不存在的話，會自動建立該資料庫  
		        db = client.getDatabase("mydb");  
		       
		  }catch (Exception e) {  
		       return e.getClass().getName() + ": " + e.getMessage();	          
	            
		  }
		      if(db!=null&&client!=null){
                            //獲取集合
                           MongoCollection<Document> documents = db.getCollection("mydb");  		       
                            Document document=documents.find().first();   
                            System.out.println(document.toJson());
                        
		      }
		     client.close();                
	}