在记录带有logback的计算数据时，我们是否应该使用isDebugEnabled（）？

Question

logger.debug("The bonus for employee {} is {}", 
   employee.getName(), employeeService.calculateBonus(employee));

Answer 1

看一下这里的示例

从2.4开始，记录器接口中添加了方法以支持lambda表达式。新方法允许客户端代码不显式检查请求的日志级别是否已启用而懒洋洋地记录消息。例如，以前可以这样写：

// pre-Java 8 style optimization: explicitly check the log level
// to make sure the expensiveOperation() method is only called if necessary
 if (logger.isTraceEnabled()) {
     logger.trace("Some long-running operation returned {}", expensiveOperation());
 }

在Java8中，使用lambda表达式也可以达到同样的效果：

// Java-8 style optimization: no need to explicitly check the log level:
// the lambda expression is not evaluated if the TRACE level is not enabled
logger.trace("Some long-running operation returned {}", () -> expensiveOperation());