我正在尝试找出登录异常时的最佳做法。
到目前为止，我每次捕获异常时都会记录。但是，当较低级别的类捕获异常（例如，来自数据库层）并将其包装在我们自己的应用程序异常中时 - 我应该也将原始异常记录在那里，还是应该让较高级别的类记录所有细节？
我的低级类由于输入参数错误而决定抛出异常的位置呢？它应该也在那里记录异常，还是让捕获代码再次记录它？
【问题讨论】：
标签： c# exception logging exception-handling
主要是您应该避免将它记录在较低级别的 catch 和较高级别的 catch 中，因为这会使日志中包含冗余信息（更不用说会占用额外的 IO 资源来写入日志）。
如果您正在寻找有关异常处理的一般最佳实践信息，this link is handy。
【讨论】：
只要您的日志记录代码 (a) 记录异常的堆栈跟踪，并且 (b) 记录整个内部异常链，您就可以在应用的最顶层只记录一次.
Microsoft 异常处理应用程序块会为您处理这两件事。我猜其他日志框架也会这样做。
【讨论】：
在我的 winform 应用程序中，我创建了一些 Observer 用于日志记录。观察者有订阅者，他们可以在某处写日志，或者处理它。 它的样子：
public static class LoggingObserver
{
/// <summary>
/// Last getted log message
/// </summary>
public static string LastLog;
/// <summary>
/// Last getted exception
/// </summary>
public static Exception LastException;
/// <summary>
/// List of log's processors
/// </summary>
public static List<BaseLogging> loggings = new List<BaseLogging>();
/// <summary>
/// Get Exception and send for log's processors
/// </summary>
/// <param name="ex">Exception with message</param>
public static void AddLogs(Exception ex)
{
LastException = ex;
LastLog = string.Empty;
foreach (BaseLogging logs in loggings)
{
logs.AddLogs(ex);
}
}
/// <summary>
/// Get message log for log's processors
/// </summary>
/// <param name="str">Message log</param>
public static void AddLogs(string str)
{
LastException = null;
LastLog = str;
foreach (BaseLogging logs in loggings)
{
logs.AddLogs(str);
}
}
/// <summary>
/// Close all processors
/// </summary>
public static void Close()
{
foreach (BaseLogging logs in loggings)
{
logs.Close();
}
}
}
订阅者的抽象类：
public abstract class BaseLogging
{
/// <summary>
/// Culture (using for date)
/// </summary>
public CultureInfo culture;
/// <summary>
/// Constructor
/// </summary>
/// <param name="culture">Culture</param>
public BaseLogging(CultureInfo culture)
{
this.culture = culture;
}
/// <summary>
/// Add log in log system
/// </summary>
/// <param name="str">message of log</param>
public virtual void AddLogs(string str)
{
DateTime dt = DateTime.Now;
string dts = Convert.ToString(dt, culture.DateTimeFormat);
WriteLine(String.Format("{0} : {1}", dts, str));
}
/// <summary>
/// Add log in log system
/// </summary>
/// <param name="ex">Exception</param>
public virtual void AddLogs(Exception ex)
{
DateTime dt = DateTime.Now;
string dts = Convert.ToString(dt, culture.DateTimeFormat);
WriteException(ex);
}
/// <summary>
/// Write string on log system processor
/// </summary>
/// <param name="str">logs message</param>
protected abstract void WriteLine(string str);
/// <summary>
/// Write string on log system processor
/// </summary>
/// <param name="ex">Exception</param>
protected abstract void WriteException(Exception ex);
/// <summary>
/// Close log system (file, stream, etc...)
/// </summary>
public abstract void Close();
}
以及记录到文件的实现：
/// <summary>
/// Logger processor, which write log to some stream
/// </summary>
public class LoggingStream : BaseLogging
{
private Stream stream;
/// <summary>
/// Constructor.
/// </summary>
/// <param name="stream">Initialized stream</param>
/// <param name="culture">Culture of log system</param>
public LoggingStream (Stream stream, CultureInfo culture)
: base(culture)
{
this.stream = stream;
}
/// <summary>
/// Write message log to stream
/// </summary>
/// <param name="str">Message log</param>
protected override void WriteLine(string str)
{
try
{
byte[] bytes;
bytes = Encoding.ASCII.GetBytes(str + "\n");
stream.Write(bytes, 0, bytes.Length);
stream.Flush();
}
catch { }
}
/// <summary>
/// Write Exception to stream
/// </summary>
/// <param name="ex">Log's Exception</param>
protected override void WriteException(Exception ex)
{
DateTime dt = DateTime.Now;
string dts = Convert.ToString(dt, culture.DateTimeFormat);
string message = String.Format("{0} : Exception : {1}", dts, ex.Message);
if (ex.InnerException != null)
{
message = "Error : " + AddInnerEx(ex.InnerException, message);
}
WriteLine(message);
}
/// <summary>
/// Closing stream
/// </summary>
public override void Close()
{
stream.Close();
}
private string AddInnerEx(Exception exception, string message)
{
message += "\nInner Exception : " + exception.Message;
if (exception.InnerException != null)
{
message = AddInnerEx(exception.InnerException, message);
}
return message;
}
}
使用：
//initialization
FileStream FS = new FileStream(LogFilePath, FileMode.Create);
LoggingObserver.loggings.Add(new LoggingStream(FS, Thread.CurrentThread.CurrentCulture));
//write exception
catch (Exception ex) {
LoggingObserver.AddLog(new Exception ("Exception message", ex));
}
//write log
LoggingObserver.AddLog("Just a log");
【讨论】：
记录你捕捉到的地方，如果你正在包装，那么你应该。如果较低的包装器没有，那么您有理由（可调试性）这样做。但是，除非您知道它是良性的或者您可以处理它，否则不要吞下异常。
我建议
try{
.
.
.
} catch(Exception ex){
... log ....
throw;
}
如果您需要记录并传递异常。
【讨论】：