日志系列之Log4j2 Garbage-free模式

Garbage-free核心思想：避免或减少对象的创建；

实现方式

1. 对象复用（threadlocal、jvm级别复用）；
2. 避免临时对象的创建；

From version 2.6, Log4j runs in “garbage free” mode by default where objects and buffers are reused and no temporary objects are allocated as much as possible. There is also a “low garbage” mode which is not completely garbage free but does not use ThreadLocal fields. This is the default mode when Log4j detects it is running in a web application.

检测web应用

　　方式：检测javax.servlet.Servlet是否在classpath上；

系统参数配置

• log4j2.enableThreadlocals - if “true” (the default for non-web applications) objects are stored in ThreadLocal fields and reused, otherwise new objects are created for each log event.
• log4j2.enableDirectEncoders - if “true” (the default) log events are converted to text and this text is converted to bytes without creating temporary objects.