如何正确关闭和打开一个Hibernate会话？ [英] How to properly close and open a Hibernate session?

问题描述

我有以下方法，每隔几秒钟插入一大批记录。在运行一段时间后，会出现如下错误：

I have the following method that inserts a large batch of records every few seconds. After some time of running I get errors like the following:

错误：通信链路故障

ERROR: Communications link failure

从服务器成功接收的最后一个数据包为523
毫秒前。最后一个成功发送到服务器的数据包是
8毫秒前。

The last packet successfully received from the server was 523 milliseconds ago. The last packet sent successfully to the server was 8 milliseconds ago.

2013年5月16日9:48:30 am com.mchange.v2.c3p0。 stmt.GooGooStatementCache
checkin语句INFO：签入语句有问题，丢弃。

May 16, 2013 9:48:30 AM com.mchange.v2.c3p0.stmt.GooGooStatementCache checkinStatement INFO: Problem with checked-in Statement, discarding.

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after statement closed.

我用于打开和关闭连接的代码如下：

The code I use to open and close connections is the following:

public DataControllerImp() {
    session = HibernateUtil.getSessionFactory().openSession();
}

@Override
public void saveMessage(ArrayList<Message> messages) {
    Transaction tx = session.beginTransaction();

    for (int i = 0; i < mesages.size(); i++) {
        Message message = messages.get(i);

        try {
            session.save(message);
            if (i % 75 == 0) { 
                // flush a batch of inserts and release memory:
                session.flush();
                session.clear();
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            session.close();
        }
    }

    tx.commit();
}

我也使用c3p0连接池。我的配置如下：

I am also using c3p0 connection pooling. My configuration looks like:

<property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>        
<property name="hibernate.c3p0.acquire_increment">1</property>
<property name="hibernate.c3p0.idle_test_period">300</property>
<property name="hibernate.c3p0.min_size">3</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.max_statements">50</property>
<property name="hibernate.c3p0.timeout">300</property>
<property name="hibernate.c3p0.acquireRetryAttempts">1</property>
<property name="hibernate.c3p0.acquireRetryDelay">250</property>

我打开和关闭连接不正确吗？

Am I opening and closing the connections incorrectly? Please let me know what I can change to stop from receiving this error and halting my program.

推荐答案

    Transaction tx = session.beginTransaction();
    try {
        for (int i = 0; i < mesages.size(); i++) {
            Message message = messages.get(i);
            session.save(message);
            if (i % 75 == 0) { 
                // flush a batch of inserts and release memory:
                session.flush();
                session.clear();
            }
        }
        tx.commit();
    }catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        tx.rollBack();
    }finally{
        session.close();
    }
}

这篇关于如何正确关闭和打开一个Hibernate会话？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！