避免字符串连接大型日志消息

Question

使用像 slf4j 这样的东西的优点之一是它通过使用参数化日志来避免字符串连接。但是，当您有很长的日志消息时，如何避免性能下降？

logger.debug("This is a very long message that prints two values." +
    " However since the message is long, we still incur the performance hit" +
    " of String concatenation when logging {} and {} ", value1, value2);

有没有办法避免这种性能成本，而不使用丑陋的 if 块来检查日志级别？

 if (logger.isDebugEnabled()) {
     logger.debug("This is a very long message that prints two values." +
         " However since the message is long, we still incur the performance hit" +
         " of String concatenation when logging {} and {}", value1, value2);
 }

Answer 1

没有字符串连接。

编译器将为您创建一个长字符串文字。