程序包 com.mysql.cj.jdbc.ha

接口 BalanceStrategy

  • 所有已知实现类:
    BestResponseTimeBalanceStrategy, RandomBalanceStrategy, SequentialBalanceStrategy, ServerAffinityStrategy
    public interface BalanceStrategy
    Implement this interface to provide a new load balancing strategy for URLs of the form "jdbc:mysql:loadbalance://..", and provide the implementation class name as the configuration parameter "loadBalanceStrategy". The driver will not pass in a Connection instance when calling init(), but it will pass in the Properties, otherwise it acts like a normal Extension. One instance of a strategy *per* JDBC connection instance will be created. If you need singleton-like behavior, you're on your own to provide it.

    • 方法详细资料

      • pickConnection

        JdbcConnection pickConnection​(InvocationHandler proxy,
                              List<String> configuredHosts,
                              Map<String,​JdbcConnection> liveConnections,
                              long[] responseTimes,
                              int numRetries)
                       throws SQLException
        Called by the driver to pick a new connection to route requests over. See LoadBalancedConnectionProxy.createConnectionForHost(String)
        参数:
        proxy - the InvocationHandler that deals with actual method calls to the JDBC connection, and serves as a factory for new connections for this strategy via the createConnectionForHost() method. This proxy takes care of maintaining the response time list, map of host/ports to live connections, and taking connections out of the live connections map if they receive a network-related error while they are in use by the application.
        configuredHosts - the list of hosts/ports (in "host:port" form) as passed in by the user.
        liveConnections - a map of host/ports to "live" connections to them.
        responseTimes - the list of response times for a transaction for each host in the configured hosts list.
        numRetries - the number of times the driver expects this strategy to re-try connection attempts if creating a new connection fails.
        返回:
        the physical JDBC connection for the application to use, based upon the strategy employed.
        抛出:
        SQLException - if a new connection can not be found or created by this strategy.