MongoDB的对象的创建

  1 package com.voice.db;
  2 
  3 import com.mongodb.DB;
  4 import com.mongodb.DBCollection;
  5 import com.mongodb.Mongo;
  6 import com.mongodb.MongoClient;
  7 import com.mongodb.MongoClientOptions;
  8 import com.mongodb.ReadPreference;
  9 import com.mongodb.ServerAddress;
 10 import com.mongodb.WriteConcern;
 11 
 12 
 13 public class MongoDB {
 14 
 15     private Mongo wMongodb;
 16     
 17     private static MongoDB instance = null;
 18     
 19     private static synchronized MongoDB GetInstance()
 20     {
 21         if(!isInstanceAlive())
 22         {
 23             instance = new MongoDB();
 24         }
 25         return instance;
 26     }
 27 
 28     /**
 29      * 判断数据库是否处于连接状态中
 30      * @return true:连接中<br/>
 31      *        false:已断开
 32      */
 33     private static boolean isInstanceAlive() {
 34         boolean retBool = false;
 35         try {
 36             // 尝试访问一次数据库
 37             DBCollection col = instance.wMongodb.getDB("database_name").getCollection("table_name");
 38             col.count();
 39             retBool = true;
 40         } catch (Exception e) {
 41             try {
 42                 instance.wMongodb.close();
 43             } catch (Exception ex) {}
 44         }
 45         return retBool;
 46     }
 47     
 48     private MongoDB()
 49     {
 50         try {
 51             MongoClientOptions.Builder voicedbBuilder = MongoClientOptions.builder();
 52             voicedbBuilder.connectTimeout(3000);
 53             voicedbBuilder.socketTimeout(6000);
 54             voicedbBuilder.autoConnectRetry(true);
 55             voicedbBuilder.connectionsPerHost(5);
 56             voicedbBuilder.readPreference(ReadPreference.secondaryPreferred());
 57             voicedbBuilder.socketKeepAlive(true);
 58             MongoClientOptions voicedbOptions = voicedbBuilder.build();
 59 
 60 //          wMongodb = new MongoClient(new ServerAddress("172.16.10.15", 27020),voicedbOptions);
 61             wMongodb = new MongoClient(new ServerAddress("localhost", 27020),voicedbOptions);
 62             
 63             DB db = wMongodb.getDB("db_name");
 64 //            DB db = wMongodb.getDB("olacloud_internal");
 65             db.authenticate("id", "id".toCharArray());
 66             db.setWriteConcern(WriteConcern.SAFE);
 67         } catch (Exception e) {
 68             // TODO Auto-generated catch block
 69             e.printStackTrace();
 70         }
 71         
 72     }
 73 
 74     /**
 75      * 获取数据库连接
 76      * @return 已经连接的数据库
 77      */
 78     public static DB getDB() {
 79         DB db = MongoDB.GetInstance().wMongodb.getDB("db_name");
 80 //        DB db = MongoDB.GetInstance().wMongodb.getDB("olacloud_internal");
 81         return db;
 82     }
 83 
 84     /**
 85      * 获取table的连接
 86      * @param tableName table名
 87      * @return table连接
 88      */
 89     public static DBCollection getDBCollection(String tableName) {
 90         DB db = MongoDB.getDB();
 91         DBCollection col = db.getCollection(tableName);
 92         return col;
 93     }
 94     
 95     /**
 96      * 关闭当前的Mongodb连接
 97      */
 98     public static void close() {
 99         if (instance != null) {
100             instance.wMongodb.close();
101         }
102     }
103 
104 }