Question

我有一个BasicDataSource实例，jdbctemplate使用它。

因此，经过一段空闲时间后，它总是说：

Caused by: java.sql.SQLException: Could not retrieve transation read-only status server
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1084)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:973)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:918)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:949)
        at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:939)
        at com.mysql.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:3976)
        at com.mysql.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:3947)
        at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2295)
        at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2262)
        at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2246)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
        at org.apache.commons.dbcp.DelegatingPreparedStatement.executeUpdate(DelegatingPreparedStatement.java:105)
        at org.springframework.jdbc.core.JdbcTemplate$2.doInPreparedStatement(JdbcTemplate.java:916)
        at org.springframework.jdbc.core.JdbcTemplate$2.doInPreparedStatement(JdbcTemplate.java:909)
        at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:644)
        ... 39 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 30,457,725 milliseconds ago.  The last packet sent successfully to the server was 0 milliseconds ago.
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
        at com.mysql.jdbc.Util.handleNewInstance(Util.java:409)
        at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1127)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3715)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3604)
        at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4155)
        at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2615)
        at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2776)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2832)
        at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2781)
        at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1569)
        at com.mysql.jdbc.ConnectionImpl.isReadOnly(ConnectionImpl.java:3970)
        ... 48 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
        at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3161)
        at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3615)
        ... 56 more

数据源的bean定义是：

<bean id="datasource" class="org.apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
    <property name="url" value="jdbc:mysql://1.2.3.4:3306/?autoReconnectForPools=true"/>
    <property name="username" value="root"/>
    <property name="password" value="password"/>
    <property name="initialSize" value="${datasourceInitialPoolSize}"/>
</bean>

有什么想法吗？

Answer 1

检查mysql服务器是否已启动。尝试在服务器计算机上运行mysql＆＃34; mysql客户端。如果服务器无法连接，您尝试连接的频率并不重要。

Answer 2

数据库连接不会永远持续下去。连接池通常允许测试池连接的有效性。您的** Number of RTC controllers. */ typedef enum { RTC_0 = 0, RTC_NUM } rtc_t; /** RTC register map. */ typedef struct { RW uint32_t rtc_ccvr; /**< Current Counter Value Register */ RW uint32_t rtc_cmr; /**< Current Match Register */ RW uint32_t rtc_clr; /**< Counter Load Register */ RW uint32_t rtc_ccr; /**< Counter Control Register */ RW uint32_t rtc_stat; /**< Interrupt Status Register */ RW uint32_t rtc_rstat; /**< Interrupt Raw Status Register */ RW uint32_t rtc_eoi; /**< End of Interrupt Register */ RW uint32_t rtc_comp_version; /**< End of Interrupt Register */ } rtc_reg_t; /* RTC register base address. */ #define RTC_BASE (0xB0000400) /* RTC register block. */ #define RTC ((rtc_reg_t *)RTC_BASE) //-------------------------------------------------------------------------- //function declaration int qm_rtc_set_alarm(const rtc_t rtc, const uint32_t alarm_val) //-------------------------------------------------------------------------- int main(void) { #define ALARM (RTC_ALARM_MINUTE / 6) rtc_set_alarm(RTC_0, (RTC[RTC_0].rtc_ccvr + ALARM)); }支持您可能会考虑使用的几个相关属性：testOnBorrow，testOnReturn，testWhileIdle，validationQueryTimeout和validationQuery。

如果您希望确保从池中获得的连接良好，请使用testOnBorrow。验证查询可以很简单，只要它至少返回一行即可。例如，＆＃34;选择1＆＃34;。

无法恢复连接池上的MySql连接

2 个答案: