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Java代码耗时统计的5种方法

news 2025/9/3 11:14:46

代码耗时统计的并不是某个方法的耗时，而是任意代码段之间的耗时。这个代码段，可能是一个方法中的几行代码，也有可能是从这个方法的某一行到另一个被调用方法的某一行，因此通过 AOP 方式是不能实现这个需求的。

使用 System函数

public static void main(String[] args) {long  start = System.currentTimeMillis();try {// 模拟业务操作Thread.sleep(1000L);} catch (InterruptedException e) {throw new RuntimeException(e);}long end = System.currentTimeMillis();System.out.println("耗时：" + (end - start) + "ms");
}或者public static void main(String[] args) {long start = System.nanoTime();try {Thread.sleep(1000L);} catch (InterruptedException e) {throw new RuntimeException(e);}long finish = System.nanoTime();long timeElapsed = finish - start;// 纳秒System.out.println(timeElapsed);
}

使用 Instant.now()函数

public static void main(String[] args) {Instant start = Instant.now();try {Thread.sleep(1000L);} catch (InterruptedException e) {throw new RuntimeException(e);}Instant finish = Instant.now();long timeElapsed = Duration.between(start, finish).toMillis();System.out.println(timeElapsed + "ms");
}

使用 Spring 框架提供的 StopWatch

public static void main(String[] args) {StopWatch watch = new StopWatch();watch.start("watcher");//some codetry {Thread.sleep(1000L);} catch (InterruptedException e) {throw new RuntimeException(e);}watch.stop();System.out.println(watch.prettyPrint());
}

使用 apache.commons 提供的 StopWatch

需要要入 apache.commons 依赖，用法上面的 spring 类似

java8 中的Function

在 jdk 1.8 中，引入了 java.util.function 包，通过该类提供的接口，能够实现在指定代码段的上下文执行额外代码的功能。

public class TraceHolderTest {public static void main(String[] args) {TraceWatch traceWatch = new TraceWatch();TraceHolder.run(traceWatch, "function1", i -> {try {TimeUnit.SECONDS.sleep(1); // 模拟业务代码} catch (InterruptedException e) {e.printStackTrace();}});String result = TraceHolder.run(traceWatch, "function2", () -> {try {TimeUnit.SECONDS.sleep(1); // 模拟业务代码return "YES";} catch (InterruptedException e) {e.printStackTrace();return "NO";}});TraceHolder.run(traceWatch, "function1", i -> {try {TimeUnit.SECONDS.sleep(1); // 模拟业务代码} catch (InterruptedException e) {e.printStackTrace();}});System.out.println(JSON.toJSONString(traceWatch.getTaskMap()));}
}/* output: 
{"function2":[{"data":1004,"taskName":"function2"}],"function1":[{"data":1001,"taskName":"function1"},{"data":1002,"taskName":"function1"}]}
*/
public class TraceHolder {/*** 有返回值调用*/public static <T> T run(TraceWatch traceWatch, String taskName, Supplier<T> supplier) {try {traceWatch.start(taskName);return supplier.get();} finally {traceWatch.stop();}}/*** 无返回值调用*/public static void run(TraceWatch traceWatch, String taskName, IntConsumer function) {try {traceWatch.start(taskName);function.accept(0);} finally {traceWatch.stop();}}
}