springboot2 log4j2 如何动态记录日志，并将日志根据api接口路径，保存到对应路径的文件中？
这个问题可以通过使用 log4j2 的 routingappender 来实现。routingappender 允许根据指定条件将日志路由到不同的目的地。
步骤：
- 在 log4j2-spring.xml 中配置 routingappender：
<configuration status="debug" monitorinterval="5">
<appenders>
<routing name="routingappender">
<routes pattern="${ctx:routingkey}">
<route key="special">
<rollingfile name="rolling-${ctx:routingkey}" filename="logs/special-${ctx:routingkey}.log"
filepattern="logs/${date:yyyy-mm}/${ctx:routingkey}-other-%d{yyyy-mm-dd}-%i.log.gz">
<patternlayout>
<pattern>%d{iso8601} [%t] %p %c{3} - %m%n</pattern>
</patternlayout>
<policies>
<timebasedtriggeringpolicy interval="6" modulate="true"/>
<sizebasedtriggeringpolicy size="10 mb"/>
</policies>
</rollingfile>
</route>
<route key="default">
<rollingfile name="rolling-default" filename="logs/default.log"
filepattern="logs/${date:yyyy-mm}/default-%d{yyyy-mm-dd}-%i.log.gz">
<patternlayout>
<pattern>%d{iso8601} [%t] %p %c{3} - %m%n</pattern>
</patternlayout>
<policies>
<timebasedtriggeringpolicy interval="6" modulate="true"/>
<sizebasedtriggeringpolicy size="10 mb"/>
</policies>
</rollingfile>
</route>
<route>
<rollingfile name="rolling-${ctx:routingkey}" filename="logs/${ctx:routingkey}/${date:yyyy-mm}.log"
filepattern="logs/${date:yyyy-mm}/${ctx:routingkey}-other-%d{yyyy-mm-dd}-%i.log.gz">
<patternlayout>
<pattern>%d{iso8601} [%t] %p %c{3} - %m%n</pattern>
</patternlayout>
<policies>
<timebasedtriggeringpolicy interval="6" modulate="true"/>
<sizebasedtriggeringpolicy size="10 mb"/>
</policies>
</rollingfile>
</route>
</routes>
</routingappender>
</appenders>
<loggers>
<root level="info">
<appenderref ref="routingappender"/>
</root>
</loggers>
</configuration>- 创建一个拦截器类，在请求处理前将接口路径动态写入到 threadcontext 中：
public class log4j2interceptor implements handlerinterceptor {
@override
public boolean prehandle(httpservletrequest request, httpservletresponse response, object handler) throws exception {
string routingkey = request.getrequesturi().substring(request.getcontextpath().length());
threadcontext.put("routingkey", routingkey);
return true;
}
@override
public void posthandle(httpservletrequest request, httpservletresponse response, object handler, modelandview modelandview) throws exception {
threadcontext.remove("routingkey");
}
}- 注册拦截器：
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
@Override
public void addInterceptors(InterceptorRegistry registry) {
InterceptorRegistration log4j2Registration = registry.addInterceptor(useLog4j2Inter());
log4j2Registration
.addPathPatterns("/**");
}
@Bean
public Log4j2Interceptor useLog4j2Inter() {
return new Log4j2Interceptor();
}
} 
