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MongoDB Java 连接池的注意事项

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Jun 07, 2016 pm 05:09 PM

mongodb

内部实现了一个连接池。Mongo对象是线程安全的，因此可以只创建一个，在多线程环境下安全使用。因此，我们可以用将Mongo变量作为

1.Mongo对象

内部实现了一个连接池。Mongo对象是线程安全的，因此可以只创建一个，在多线程环境下安全使用。因此，我们可以用将Mongo变量作为一个Singleton类的成员变量，从而保证只创建一个连接池。Mongo.close方法将关闭当前所有活跃的连接。所以要在web工程被从Tomcat或者GlassFish容器中注销的时候确保调用close方法。

2.DB对象

DB对象可以通过Mongo.get方法获得，代表了和数据库的一个连接。默认情况下，当执行完数据库的查询或者更新操作后，连接将自动回到连接池中。不需要我们手动调用代码放回池中。至于如何实现，，我猜测是update,query,save方法内部有finally块，那里面有还连接到池中的代码。

3.手动还连接入池

DB对象也允许在一个连接上执行多个操作，比如下面的代码：

[java]

requestStart 会让自动还连接入池失效，因此必须确保requestDone一定能够被调用。这里应该用finally块会更严密一些。

4.示例代码，下面的类实现了Lazy loading的Singleton模式，里面的成员变量Mongo mongo因此只会实例化一次。注意连接池大小和重连设置。

[java]

linux

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