log4net 修改日志输出格式的绝对文件路径为相对文件名

log4net-1.2.11 输出日志格式%file输出的是绝对文件路径，其实没有必要，只需要输出文件名即可。

修改源码：log4net-1.2.11\src\Layout\Pattern\FileLocationPatternConverter.cs

writer.Write(Path.GetFileName(loggingEvent.LocationInformation.FileName));

#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0 //
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

using System;
using System.Text;
using System.IO;

using log4net.Core;

namespace log4net.Layout.Pattern
{
/// <summary>
/// Writes the caller location file name to the output
/// </summary>
/// <remarks>
/// <para>
/// Writes the value of the <see cref="LocationInfo.FileName"/> for
/// the event to the output writer.
/// </para>
/// </remarks>
/// <author>Nicko Cadell</author>
internal sealed class FileLocationPatternConverter : PatternLayoutConverter
{
/// <summary>
/// Write the caller location file name to the output
/// </summary>
/// <param name="writer"><see cref="TextWriter" /> that will receive the formatted result.</param>
/// <param name="loggingEvent">the event being logged</param>
/// <remarks>
/// <para>
/// Writes the value of the <see cref="LocationInfo.FileName"/> for
/// the <paramref name="loggingEvent"/> to the output <paramref name="writer"/>.
/// </para>
/// </remarks>
override protected void Convert(TextWriter writer, LoggingEvent loggingEvent)
{
writer.Write(Path.GetFileName(loggingEvent.LocationInformation.FileName));
}
}
}

重新编译即可