使用ThreadLocal配合StopWatch简化代码耗时打印的代码量。

工具类提供StopWatch默认输出格式和支持自定义打印输出格式，具体代码如下：

import org.springframework.util.StopWatch;

import lombok.extern.slf4j.Slf4j;

/**
 * 使用线程变量全局打印耗时
 * 
 * @author jun.chen
 *
 */
@Slf4j
public class CostPrintUtil {

	private static final ThreadLocal<StopWatch> stopWatchLocal = new ThreadLocal<>();

	/**
	 * 初始化StopWatch
	 * 
	 * @param title
	 */
	public static void init(String title) {
		initStopWatch(title);
	}

	/**
	 * 开始记录某段代码的耗时
	 * 
	 * @param taskName
	 */
	public static void startWatch(String taskName) {
		StopWatch stopWatch = getStopWatch();

		if (stopWatch.isRunning()) {
			stopWatch.stop();
			log.debug("{} is Running,stop it.", stopWatch.getLastTaskName());
		}
		stopWatch.start(taskName);
	}

	/**
	 * 结束记录
	 * 
	 * @param taskName
	 */
	public static void stopWatch() {
		StopWatch stopWatch = getStopWatch();
		if (stopWatch.isRunning()) {
			stopWatch.stop();
		} else {
			log.debug("stopWatch is not start.");
		}
	}

	/**
	 * 结束StopWatch并StopWatch对象
	 * 
	 * @return
	 */
	public static StopWatch end() {
		StopWatch stopWatch = getStopWatch(true);
		if (null == stopWatch) {
			throw new RuntimeException("当前线程内没有StopWatch对象.");
		}
		if (stopWatch.isRunning()) {
			stopWatch.stop();
			log.debug("{} is Runnong,stop it.", stopWatch.getLastTaskName());
		}
		clearStopWatch();
		return stopWatch;
	}

	/**
	 * 结束并打印 默认使用stopWatch.prettyPrint()
	 * 
	 */
	public static void endPrint() {
		endPrint(null);
	}

	/**
	 * 结束并打印
	 * 
	 * @param helper
	 */
	public static void endPrint(PrintHelper helper) {
		StopWatch stopWatch = end();
		if (null != helper) {
			helper.print(stopWatch);
		} else {
			log.info(stopWatch.prettyPrint());
		}
	}

	/**
	 * 自定义打印输出
	 * 
	 * @author jun.chen
	 *
	 */
	interface PrintHelper {
		void print(StopWatch stopWatch);
	}

	private static void initStopWatch(String title) {
		stopWatchLocal.set(new StopWatch(title));
	}

	private static StopWatch getStopWatch() {
		return getStopWatch(false);
	}

	private static StopWatch getStopWatch(boolean isEnd) {
		return getStopWatch("", isEnd);
	}

	/**
	 * 获取当前线程内的StopWatch
	 * 
	 * @param title
	 * @param isEnd
	 * @return
	 */
	private static StopWatch getStopWatch(String title, boolean isEnd) {
		StopWatch stopWatch = stopWatchLocal.get();
		// 非结束时获取StopWatch允许初始化
		if (null == stopWatch && !isEnd) {
			initStopWatch(title);
		}
		return stopWatchLocal.get();
	}

	private static void clearStopWatch() {
		stopWatchLocal.remove();
	}

	public static void main(String[] args) throws InterruptedException {
		// a. 正常使用
		CostPrintUtil.init("示例A");
		CostPrintUtil.startWatch("TaskA - 1");
		Thread.sleep(200);
		CostPrintUtil.stopWatch();
		CostPrintUtil.startWatch("TaskA - 2");
		Thread.sleep(300);
		CostPrintUtil.stopWatch();
		CostPrintUtil.startWatch("TaskA - 3");
		Thread.sleep(100);
		CostPrintUtil.stopWatch();
		CostPrintUtil.endPrint();

		// b. 未初始化直接start
		CostPrintUtil.startWatch("TaskB - 1");
		Thread.sleep(200);
		CostPrintUtil.stopWatch();
		CostPrintUtil.endPrint();

		// c. 未stop直接end
		CostPrintUtil.startWatch("TaskC - 1");
		Thread.sleep(200);
		CostPrintUtil.endPrint();

		// d. 多次end
		CostPrintUtil.startWatch("TaskD - 1");
		Thread.sleep(200);
		CostPrintUtil.endPrint();
		try {
			CostPrintUtil.endPrint();
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		// e.多次start 和 多次stop
		CostPrintUtil.startWatch("TaskE - 1");
		Thread.sleep(200);
		CostPrintUtil.startWatch("TaskE - 2");
		Thread.sleep(200);
		CostPrintUtil.stopWatch();
		CostPrintUtil.stopWatch();
		CostPrintUtil.endPrint();

		// f. 自定义打印输出
		CostPrintUtil.startWatch("自定义打印耗时(重写接口实现)");
		Thread.sleep(200);
		CostPrintUtil.stopWatch();
		// 重写接口实现
		CostPrintUtil.endPrint(new PrintHelper() {

			@Override
			public void print(StopWatch stopWatch) {
				log.info("TaskName:{} Cost:{}", stopWatch.getLastTaskName(), stopWatch.getTotalTimeSeconds());
			}
		});
		// 使用lambda表达式
		CostPrintUtil.startWatch("自定义打印耗时(lambda表达式)");
		Thread.sleep(200);
		CostPrintUtil.stopWatch();
		CostPrintUtil.endPrint((stopWatch) -> {
			String lastTaskName = stopWatch.getLastTaskName();
			long lastTaskTimeMillis = stopWatch.getLastTaskTimeMillis();
			log.info("Task: {} Costs: {}ms", lastTaskName, lastTaskTimeMillis);
		});
	}

}

其中main函数提供了一些使用示例，有疑问或有改善意见的欢迎留言 （ ^_^ ）。