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我在 Web 服务中遇到了 MySQL 连接。

public class DBAccessLayer
{
    private Connection connection = null;
    private Statement statement = null;
    private String DBFormatter = "'";
    private String key;
    private static DataSource datasource = null;
    private static boolean _isInitiated = false;
    private static boolean _isInitializing = false;

    public DBAccessLayer()
    {
        key = ConstantValues.getKey();
        SetPoolSettings();
    }

    private void SetPoolSettings()
    {
        try
        {
            if (!_isInitiated && !_isInitializing)
            {
                _isInitializing = true;

                PoolProperties p = new PoolProperties();
                p.setUrl("jdbc:mysql://localhost:3306/DBName?autoReconnect=true");
                p.setDriverClassName("com.mysql.jdbc.Driver");
                p.setUsername("root");
                p.setPassword("password");
                p.setJmxEnabled(true);
                p.setTestWhileIdle(false);
                p.setTestOnBorrow(true);
                p.setValidationQuery("SELECT 1");
                p.setTestOnReturn(false);
                p.setValidationInterval(30000);
                p.setTimeBetweenEvictionRunsMillis(30000);
                p.setMaxActive(100);
                p.setInitialSize(10);
                p.setMaxWait(10000);
                p.setRemoveAbandonedTimeout(60);
                p.setMinEvictableIdleTimeMillis(30000);
                p.setMinIdle(10);
                p.setLogAbandoned(true);
                p.setRemoveAbandoned(true);
                p.setFairQueue(true);
                p
                    .setJdbcInterceptors("org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer");
                datasource = new DataSource();
                datasource.setPoolProperties(p);

                _isInitiated = true;
            }
        }
        finally
        {
            _isInitializing = false;
        }
    }

    public void OpenConnection() throws SQLException
    {
        if (connection == null || connection.isClosed())
            connection = datasource.getConnection();

        if (statement == null || statement.isClosed())
            statement = connection.createStatement();

    }

    public Statement getStatement() throws Exception
    {
        if (connection == null || connection.isClosed())
            connection = datasource.getConnection();
        statement = connection.createStatement();
        return statement;
    }

    public void CloseConnection()
    {
        try
        {
            if (statement != null)
                statement.close();
        }
        catch (Exception ignore)
        {
            ignore.printStackTrace();
        }

        try
        {
            if (connection != null)
                connection.close();
        }
        catch (Exception ignore)
        {
            ignore.printStackTrace();
        }
    }
}

这是我用来连接 Web 服务中的数据库的课程。我有一些使用相同 Web 服务运行的石英计划作业。

我在每个 Web 服务方法调用和每个作业开始时调用 OpenConnection() 方法，最后阻塞 CloseConnection()。

但是我经常收到此错误，而我在尝试中仅关闭一次连接 - finally 块。

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException：语句关闭后不允许任何操作。

所以我的网络服务方法看起来像

private DBAccessLayer _DBAccessLayer = null;

private DBAccessLayer getDBAccessLayer()
{
    if (_DBAccessLayer == null)
        _DBAccessLayer = new DBAccessLayer();
    rerurn _DBAccessLayer;
}

public void dummyCall()
{
    try
    {

        getDBAccessLayer.getStatement().executeQuery("Some query");

    }
    finally
    {
        getDBAccessLayer.CloseConnection();
    }
}
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