nanotime_nanotime在MacOS上做了什么？_System.nanoTime()完全没用吗？ - 腾讯云开发者社区

Java精确测量代码运行时间： long startTime = System.nanoTime(); //開始時間 for(int i = 0;i<10000;i++...){ ; } long consumingTime = System.nanoTime() - startTime; //消耗時間 ...System.out.println(consumingTime); System.out.println(consumingTime/1000+"微秒"); JDK的解释： public static long nanoTime...For example, to measure how long some code takes to execute: long startTime = System.nanoTime();...long estimatedTime = System.nanoTime() - startTime; 返回： The current value of the system timer, in nanoseconds

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聊聊resilience4j的CircuitBreaker

{ CircuitBreakerUtils.isCallPermitted(circuitBreaker); long start = System.nanoTime...{ T returnValue = supplier.apply(); long durationInNanos = System.nanoTime...open", circuitBreaker.getName()))); } else { final long start = System.nanoTime...(); try{ runnable.run(); long durationInNanos = System.nanoTime...(); try{ runnable.run(); long durationInNanos = System.nanoTime

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java集合【12】——— ArrayList，LinkedList，Vector的相同点与区别是什么？

static void addLinkedList(){ List list = new LinkedList(); long startTime = System.nanoTime...for(int i=0;i<100000;i++){ list.get(i); } long endTime = System.nanoTime...for(int i=0;i<100000;i++){ list.get(i); } long endTime = System.nanoTime...for(int i=0;i<100000;i++){ list.get(i); } long endTime = System.nanoTime...list.isEmpty()) { } long endTime = System.nanoTime(); System.out.println((endTime

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如何高效的判断一个数组里是否含特定元素判断一个数组里是否含有特定元素的四种方法时间复杂度测试小结

String[] { "CD", "BC", "EF", "DE", "AB"}; //using list long startTime = System.nanoTime...for(int i=0;i<1000000;i++) useList(arr, "A"); long endTime = System.nanoTime...for (int i = 0; i < 1000000; i++) { useSet(arr, "A"); } endTime = System.nanoTime...for (int i = 0; i < 1000000; i++) { loop(arr, "A"); } endTime = System.nanoTime...String[] { "CD", "BC", "EF", "DE", "AB"}; //using list long startTime = System.nanoTime

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遍历List效率分析

/*使用迭代器去遍历*/ long time1 = System.nanoTime(); Iterator iterator = spiderResults.iterator...()-time1)+" ms"); /*使用foreach循环去遍历*/ long time2 = System.nanoTime(); for(ApiResponse i:spiderResults...) { } System.out.println("Foreach程序耗时："+(System.nanoTime()-time2)+" ms"); /*使用for循环遍历*/ long time3...= System.nanoTime(); for(int l=0;l<spiderResults.size();l++){ ApiResponse o = spiderResults.get(l...); } System.out.println("For循环程序耗时："+(System.nanoTime()-time3)+" ms"); /*使用Stream遍历*/ long time4

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HBase行锁与MVCC分析

() - time)); time = System.nanoTime(); Integer lid = getLock...(updateLockTime.get() + (System.nanoTime() - time)); time = System.nanoTime();...() - time)); time = System.nanoTime(); kvset.add(new KeyValue...() - time)); time = System.nanoTime(); mvcc.completeMemstoreInsert...(localizedWriteEntry); mvccTime.set(mvccTime.get() + (System.nanoTime() - time));

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toArray指定的容量和效率关系

COUNT); for (int i = 0; i < COUNT; i++) { list.add(i * 1.0); } long start = System.nanoTime...notEnoughArray = new Double[COUNT - 1]; list.toArray(notEnoughArray); long middle1 = System.nanoTime...Double[] equalArray = new Double[COUNT]; list.toArray(equalArray); long middle2 = System.nanoTime...Double[] doubleArray = new Double[COUNT * 2]; list.toArray(doubleArray); long middle3 = System.nanoTime...(); list.toArray(new Double[0]); long end = System.nanoTime(); long notEnoughArrayTime =

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【蓝桥杯Java_C组·从零开始卷】第八节、集合——list详解(ArrayList、 LinkedList 和 Vector之间的区别)

(); for (int i = 0; i < 100000; i++) { arrayList.add(i); } long endTime = System.nanoTime(...(); for (int i = 0; i < 100000; i++) { linkedList.add(i,i); } endTime = System.nanoTime();...(); for (int i = 0; i < 10000; i++) { linkedList.get(i); } endTime = System.nanoTime();...(); for (int i = 9999; i >= 0; i--) { arrayList.remove(i); } endTime = System.nanoTime();...(); for (int i = 9999; i >= 0; i--) { linkedList.remove(i); } endTime = System.nanoTime();

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Netty杂记

final long ioTime = System.nanoTime() - ioStartTime; // 3.执行任务...ScheduledFutureTask.nanoTime() + timeoutNanos : 0; long runTasks = 0; long lastExecutionTime;...for (;;) { safeExecute(task); runTasks ++; // 每64个任务检查一次超时,因为nanoTime(...)比较昂贵. // Check timeout every 64 tasks because nanoTime() is relatively expensive. //...那我们看一下java.lang.System#nanoTime源码. // 源码位置: java.lang.System#nanoTime public static native long nanoTime

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字符串逆序方法比较

(); reversePrint(s, 0); // 直接打印 long e1 = System.nanoTime(); System.out.println...System.out.println((e1-l1)+"ns"); System.out.println(); long l2 = System.nanoTime...(); System.out.println(reverseString(s, 0)); // 直接递归到底层返回逆序回串 long e2 = System.nanoTime...(); System.out.println(reverseString1(s)); // 二分递归到底层返回逆序串 long e3 = System.nanoTime(...System.out.println(reverseString2(s)); // 和java的StringBuilder一样的实现 long e4 = System.nanoTime

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java集合【12】——— ArrayList，LinkedList，Vector的相同与区别？

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Java程序运行纳秒级差值计算

0.000001 毫秒 1纳秒=0.00000 0001秒其实翻过来看更清晰，咱们看毫秒啊 100000纳秒=1毫秒 java的System.currentTimeMillis()和System.nanoTime...()区别: java中System.nanoTime()返回的是纳秒， nanoTime而返回的可能是任意时间，甚至可能是负数…… java中System.currentTimeMillis(...main(String[] args) { //1纳秒=0.000001 毫秒 //100000纳秒=1毫秒 int count=100000; long start = System.nanoTime...for (int i = 1; i <= count; i++) { sum+=i; } System.out.println(sum); long end = System.nanoTime

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聊聊Elasticsearch RestClient的DeadHostState

should be retried, false otherwise */ boolean shallBeRetried() { return timeSupplier.nanoTime...{ TimeSupplier DEFAULT = new TimeSupplier() { @Override public long nanoTime...() { return System.nanoTime(); } @Override public...String toString() { return "nanoTime"; } }; long nanoTime...previousDeadHostState.failedAttempts * 0.5 - 1) DeadHostState提供了shallBeRetried方法，其判断逻辑为timeSupplier.nanoTime

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Java的HashSet vs. TreeSet vs. LinkedHashSet比较

>(); LinkedHashSet linkedSet = new LinkedHashSet(); // start time long startTime = System.nanoTime...) { int x = r.nextInt(1000 - 10) + 10; hashSet.add(new Dog(x)); } // end time long endTime = System.nanoTime...= endTime - startTime; System.out.println("HashSet: " + duration); // start time startTime = System.nanoTime...; i++) { int x = r.nextInt(1000 - 10) + 10; treeSet.add(new Dog(x)); } // end time endTime = System.nanoTime...= endTime - startTime; System.out.println("TreeSet: " + duration); // start time startTime = System.nanoTime

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PrintWriter(三种使用方式效率对比)——单位(纳秒)

public class demo { public static void main(String[] args) { int count=100; long start = System.nanoTime...OutputStreamWriter(System.out))); for (int i = 0; i < count; i++) { pw.println(i); } long end = System.nanoTime...public class demo { public static void main(String[] args) { int count = 100; long start = System.nanoTime...public class demo { public static void main(String[] args) { int count = 100; long start = System.nanoTime...PrintWriter(System.out); for (int i = 0; i < count; i++) { pw.println(i); } long end = System.nanoTime

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性能有点不错的时间工具类

yyyy-MM-dd HH:mm:SSS"; public static void main(String[] args) { // 原始方式 long dateTimeStart = System.nanoTime...DateTimeFormatter.ofPattern(PATTERN))).limit(10000).collect(Collectors.toList()); long dateTimeEnd = System.nanoTime...dateTimeEnd - dateTimeStart) / (1000.0 * 1000.0) + "ms"); // 工具类，手动获取实例 long start = System.nanoTime...format(System.currentTimeMillis())).limit(10000).collect(Collectors.toList()); long end = System.nanoTime...System.currentTimeMillis())).limit(10000).collect(Collectors.toList()); long patternEnd = System.nanoTime

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removeIf

Stream.iterate(0, e -> ++e).limit(20).collect(Collectors.toList()); long filterStart = System.nanoTime...intList.stream().filter(a -> a % 2 == 0).collect(Collectors.toList()); long filterEnd = System.nanoTime...执行了" + ((filterEnd - filterStart) / (1000.0 * 1000.0)) + "ms"); long removeIfStart = System.nanoTime...= 0); long removeIfEnd = System.nanoTime(); System.out.println("removeIfEnd执行了" + ((removeIfEnd

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老徐和阿珍的故事：ArrayList和LinkedList的效率到底哪个高？

所耗费的时间（单位：ms） */ public static long addHeader(List list, int count) { long start = System.nanoTime...for (int i = 0; i < count; i++) { list.add(0, "onemore-" + i); } long end = System.nanoTime...0; i < count; i++) { list.add(list.size() / 2, "onemore-" + i); } long end = System.nanoTime...for (int i = 0; i < count; i++) { list.add("onemore-" + i); } long end = System.nanoTime...(); for (int i = 0; i < count; i++) { list.remove(0); } long end = System.nanoTime

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Java 中的 try catch 影响性能吗？

实验首先，我们看看没有try-catch情况下，进行100万次加法的耗时： long start = System.nanoTime(); int a = 0; for (int i = 0; i <...1000000; i++) { a++; } System.out.println(System.nanoTime() - start); 经过5次统计，其平均耗时为：1816048纳秒，即1.8...接着，我们来看看在有try-catch情况下，进行100万次加法的耗时： long start = System.nanoTime(); int a = 0; for (int i = 0; i < 1000000...a++; } catch (Exception e) { e.printStackTrace(); } } System.out.println(System.nanoTime...我们再来看看，如果try-catch抛出异常，进行100万次加法的耗时： long start = System.nanoTime(); int a = 0; for (int i = 0; i < 1000000

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聊聊Elasticsearch RestClient的DeadHostState

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Java精确测量代码运行时间代码执行时间纳秒 nanoTime

聊聊resilience4j的CircuitBreaker

java集合【12】——— ArrayList，LinkedList，Vector的相同点与区别是什么？

如何高效的判断一个数组里是否含特定元素判断一个数组里是否含有特定元素的四种方法时间复杂度测试小结

遍历List效率分析

HBase行锁与MVCC分析

toArray指定的容量和效率关系

【蓝桥杯Java_C组·从零开始卷】第八节、集合——list详解(ArrayList、 LinkedList 和 Vector之间的区别)

Netty杂记

字符串逆序方法比较

java集合【12】——— ArrayList，LinkedList，Vector的相同与区别？

Java程序运行纳秒级差值计算

聊聊Elasticsearch RestClient的DeadHostState

Java的HashSet vs. TreeSet vs. LinkedHashSet比较

PrintWriter(三种使用方式效率对比)——单位(纳秒)

性能有点不错的时间工具类

removeIf

老徐和阿珍的故事：ArrayList和LinkedList的效率到底哪个高？

Java 中的 try catch 影响性能吗？

聊聊Elasticsearch RestClient的DeadHostState

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