向 MySQL 数据库写入异常时出现 Log4Net 异常答案

【问题标题】：Log4Net exception while writing exception to MySQL database向 MySQL 数据库写入异常时出现 Log4Net 异常
【发布时间】：2016-03-10 11:35:55
【问题描述】：

记录异常时，它会正确显示在命令行中。但是，它不会写入数据库。其他参数记录正确。

在我的app.config中，异常配置如下：

<commandText value="INSERT INTO logs (time, log_level, logger, message, exception, thread) VALUES (?time, ?log_level, ?logger, ?message, ?exception, ?thread)" />

参数：

<parameter>
    <parameterName value="exception" />
    <dbType value="String" />
    <size value="2000" />
    <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%exception" />
    </layout>
</parameter>

我正在测试：

try
{
    throw new DivideByZeroException();
}
catch (Exception e)
{
    log.Error("", e);
}

我启用了 Log4Net 调试并得到以下输出：

log4net: Hierarchy Threshold []
A first chance exception of type 'System.FormatException' occurred in mscorlib.dll
log4net:ERROR [CustomAdoNetAppender] ErrorCode: GenericFailure. Exception while writing to database
12:25:37,902 [Game.Program] {exceptions} () ERROR:  System.DivideByZeroException: Attempted to divide by zero.
   at Game.Program.Init() in --:line 98

log4net:ERROR [CustomAdoNetAppender] ErrorCode: GenericFailure. Exception while writing to database
System.FormatException: Input string was not in a correct format.
   at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
   at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
   at System.String.System.IConvertible.ToInt32(IFormatProvider provider)
   at System.Convert.ToInt32(Object value)
   at MySql.Data.Types.MySqlInt32.MySql.Data.Types.IMySqlValue.WriteValue(MySqlPacket packet, Boolean binary, Object val, Int32 length)
   at MySql.Data.MySqlClient.MySqlParameter.Serialize(MySqlPacket packet, Boolean binary, MySqlConnectionStringBuilder settings)
   at MySql.Data.MySqlClient.Statement.SerialiSystem.FormatException: Input string was not in a correct format.
   at System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal)
   at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info)
   at System.String.System.IConvertible.ToInt32(IFormatProvider provider)
   at System.Convert.ToInt32(Object value)
   at MySql.Data.Types.MySqlInt32.MySql.Data.Types.IMySqlValue.WriteValue(MySqlPacket packet, Boolean binary, Object val, Int32 length)
   at MySql.Data.MySqlClient.MySqlParameter.Serialize(MySqlPacket packet, Boolean binary, MySqlConnectionStringBuilder settings)
   at MySql.Data.MySqlClient.Statement.SerializeParameter(MySqlParameterCollection parameters, MySqlPacket packet, String parmName, Int32 parameterIndex)
   at MySql.Data.MySqlClient.Statement.InternalBindParameters(String sql, MySqlParameterCollection parameters, MySqlPacket packet)
   at MySql.Data.MySqlClient.Statement.BindParameters()
   at MySql.Data.MySqlClient.Statement.Execute()
   at MySql.Data.MySqlClient.PreparableStatement.Execute()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at log4net.Appender.AdoNetAppender.SendBuffer(IDbTransaction dbTran, LoggingEvent[] events)
   at log4net.Appender.AdoNetAppender.SendBuffer(LoggingEvent[] events)
zeParameter(MySqlParameterCollection parameters, MySqlPacket packet, String parmName, Int32 parameterIndex)
   at MySql.Data.MySqlClient.Statement.InternalBindParameters(String sql, MySqlParameterCollection parameters, MySqlPacket packet)
   at MySql.Data.MySqlClient.Statement.BindParameters()
   at MySql.Data.MySqlClient.Statement.Execute()
   at MySql.Data.MySqlClient.PreparableStatement.Execute()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader()
   at MySql.Data.MySqlClient.MySqlCommand.ExecuteNonQuery()
   at log4net.Appender.AdoNetAppender.SendBuffer(IDbTransaction dbTran, LoggingEvent[] events)
   at log4net.Appender.AdoNetAppender.SendBuffer(LoggingEvent[] events)

【问题讨论】：

您尝试插入的值似乎存在问题。我认为您有一个 NUMBER 类型的列。您可以发布您尝试为该列插入的值吗？或者更好的是，所有绑定变量的值。
直接问，?time、?log_level、?logger、?message、?exception、?thread变量的值是多少？
这些都是Log4Net的内部值。除异常外，它们都正确记录到数据库中。

标签： c# mysql database logging log4net

【解决方案1】：

我发现了错误。

显然，我在调用测试异常函数时添加了一些尚未初始化的全局变量。我将这些变量初始化为空字符串和零，它起作用了。

【讨论】：

哪些变量？