System nanotime vs system currenttimemillis. And, System. Therefore, if the elaps...

System nanotime vs system currenttimemillis. And, System. Therefore, if the elapsed time is measured in a different time unit we must convert it accordingly. currentTimeMillis() returns so called “time-of-day clock” time or wall-clock time, so it’s good for time-stamping. nanoTime () serve different timing purposes in Java. currentTimeMillis() returns the time in milliseconds since midnight, January 1, 1970 UTC. In a game loop everyone uses System. nanoTime() gives you access to a high-resolution time source (nanoseconds) that is designed for measuring elapsed time and it is not related to the system clock or any “wall-clock”, see the javadoc of System. currentTimeMillis () method returns the current time in milliseconds. The first obvious reason is nanoTime () gives more precise timing and the other reason I read that the latter is affected by adjustments to the system’s real-time clock. nanoTime () 之间的时间段如何转换成ms 在Java中使用System. currentTimeMillis() will give you the most accurate possible elapsed time in milliseconds since the epoch, but System. currentTimeMillis() for elapsed time — it’s a legacy wall-clock API affected by clock adjustments. currentTimeMillis() is based on the system clock, which is, most of the time, based on a quartz clock inside a computer. Jul 23, 2017 · Multi-threaded performance The currentTimeMillis() based on HPET runs for 640 ns (1. currentTi Oct 25, 2024 · 引言 在现代软件开发中，时间管理是一个至关重要的环节。无论是性能优化、日志记录，还是定时任务，都需要精确的时间测量和控制。Java作为一门广泛应用的开发语言，提供了多种时间管理的API，其中System. But is it always efficient on the Feb 2, 2024 · long endNanoTime = System. currentTimeMillis (), and help you pick the right one for your needs. Is this per core or for the entire system? Let’s run a similar test to Time. nanoTime ()的精确度更高一些，如今的硬件设备性能越来越好，如果要更精密计算执行某行代码或者某块代码所消耗的时间，该方法会测量得更精确。 2. It is not accurate and it drifts. nanoTime() is less about precision but more about accuracy. nanoTime () batter than System. Oct 15, 2024 · System. currentTimeMillis Sep 5, 2015 · Bit late to the party, but I'd say nanoTime is unreliable for long intervals, since nanoTime() and currentTime (either System. There are two standard ways to time operations in Java: System. nanoTime and System. currentTimeMillis() or comments on this will be most appreciated. sleep(millls), Object. currentTimeMillis() 和 System. Dec 26, 2022 · Java offers two basic methods for measuring time value: currentTimeMillis and nanoTime. elapsedRealtimeNanos() - Counts elapsed time even on deep sleep, but requires API level 17. SystemClock. currentTimeMillis(): Designed to report the wall-clock time (the time displayed on a device). java, but start N threads, where N is between 1 and 24 (the total number of cores in our dual-processor system, including hyper-threading ones). nanoTime两个时间API的区别，详细解释了它们的精度、应用场景及各自的优缺点，帮助开发者在不同的需求场景下选择合适的时间测量方法。 Oct 30, 2022 · System. The difference between two calls to System. Jul 4, 2022 · testing. This results in a non-consistent nanoTime over each run. nanoTime () returns nanoseconds, indicating that System. currentTimeMillis() used! Obviously the conversion looks a bit different as granularity of nanoTime() is higher, but it’s the same Posix call! This implies that under some circumstances System. currentTimeMillis ()是什么 System. currentTimeMillis ()与System. You can compare such values obtained in different JVMs even on different machines and this is as good as synchronization of clocks on these machines. Choose nanoTime) for precise elapsed time measurements in performance-critical code, though it requires 100+ cycles. nanoTime() and we disregard the variance in cost of commands, it appears as if there would be not a linear graph on the same resolution. nanoTime()？他们的移动变化与自上次调用以来所经过的时间成正比，我希望尽可能精确。我读到过，不同操作系统之间存在一些严重的时间分辨率问题(即Mac / Linux的分辨率几乎为1ms，而Windows的 Jun 18, 2012 · Java timing, System. nanoTime() that are a substantial fraction of a second apart is bound to be a large number. nanoTime() that relate to time measurement. currentTimeMillis比较 首先： currentTimeMillis返回的是系统当前时间和1970-01-01之前间隔时间的毫秒数，如果系统时间固定则方法返回值也是一定的（这么说是为了强调和nanoTime的区别），精确度是毫秒级别的 nanoTime的返回值本身则没有什么意义，因为它基于的时间点是随机的，甚至可能 Mar 20, 2012 · 이러한 영향의 정도는 플랫폼에 따라 다르다. currentTimeMillis()는 현재 시간을 밀리초 단위로 반환한다. currentTimeMillis (). The value returned represents nanoseconds since some fixed but arbitrary time (in the future, so values may be negative) and provides nanosecond precision, but not necessarily nanosecond accuracy. nanoTime () le dará un tiempo preciso de nanosegundos, en relación con algún punto arbitrario. Example: Aug 5, 2025 · 结论 System. Is System. 5M operations/second). nanoTime () 主要被称为昂贵调用，用于获取更具体的时间值。而且，System. nanoTime ()方法在Java环境中可以帮助找到两个指针之间的差异。 简单来说，它可以在进程开始前获取一个时间读数，然后在执行方法后获取另一个时间读数。 💡 Exploring Java's System. The only difference is the method used to get timestamps – nanoTime () instead of currentTimeMillis (). nanoTime () measure "wall clock" time, at least in the sense that the difference between 2 measurements is how much time has passed on A clock. nanoTime ()没有什么意义，因为该值是随机的，无法表示当前的时间。 Nov 12, 2025 · System. nanoTime () will always produce positive elapsed time, currentTimeMillis will not (e. nanoTime(): Designed specifically for measuring elapsed time intervals. System API currentTimeMillis() Returns the current time in milliseconds nanoTime() Returns the current value of the running Java Virtual Machine's high resolution t Dec 20, 2019 · Java offers two basic primitives for measuring time: System. I just rearranged that equation and tried making a clock such that currentTime() = baseTime + nanoTime() - baseNanos Answer In Java, both System. Is system nanoTime () reliable? May 1, 2024 · There are two similar methods in Java: System. nanoTime() uses the Unix epoch as a reference thus it can go back in time! Sep 1, 2021 · 1、System. In this example, currentTimeMillis () is used to measure elapsed time in milliseconds, while nanoTime () is used to measure elapsed time in nanoseconds. now for the current time on the clock, captured in microseconds in Java 9+ (milliseconds in Java 8), with nanoseconds resolution. nanoTime () in Java, including usage and best practices. In this tutorial, we will learn two most commonly used Java System functions - System. Jul 29, 2025 · “Java Time Measurement: System. Nov 4, 2025 · Explore the differences between Java's System. currentTimeMillis (), which is optimized for retrieving the current wall-clock time. Call System. nanoTime () 's disadvantage is it doesn't have a fixed reference point Mar 26, 2025 · The code is basically the same as before. currentTimeMillis in Java for accurate time measurements in your applications. Unlike System. nanoTime Jun 12, 2021 · In Java (but other platforms has a solution for this too), System. nanoTime() but for something like animations, the speed of something, etc some people use System. nanoTime () and when to use each. accept(millisTest); } } 因为我用的是 Windows，所以执行输出当中 System. currentTimeMillis()"); testing. currentTimeMillis() and store as starting "wall clock" time: long currentTimeMillis0. ----- So you plotted currentTime() - baseTime vs nanoTime() - baseNanos. currentTimeMillis是 System. This is in contrast to System. currentTimeMillis () use then? If you look at the source code of Clock. Which one sh Jul 29, 2025 · “Java Time Measurement: System. 根据报告的信息，读取全局变量自然非常快-大约6个周期。 System. 10 -9 seconds, as described in the javadoc. currentTimeMillis () but does it persist over sleep? Asked 12 years, 2 months ago Modified 12 years, 2 months ago Viewed 5k times This is the basis for most interval timing such as Thread. currentTimeMillis()还是System. accept(nanoTest); System. currentTimeMillis ()提供真实世界时间，但存在性能陷阱和NTP同步问题；System. Dec 29, 2024 · System. The latter is monotonic, whereas the first may make arbitrary backward or forward jumps as the user or NTP daemon changes the system clock, or leap seconds are inserted. nanoTime() is that System. nanoTime () 和System. The first is that they are at different levels of precision. Most methods that accept a timestamp value currently expect the uptimeMillis() clock. For example, many operating systems measure time in units of tens of milliseconds. currentTimeInMillis() . nanoTime() is more precise than uptimeMillis(), but that's only useful for micro-benchmarks. 시간은 계속 흘러가기 때문에 시간을 고유한 값으로 사용하는 경우가 많다. nanoTime()은 현재 시간을 나노초 단위로 반환한다. In a comment in the millis() method, it says (quoting Java 15): System. nanoTime (): Why NanoTime is Preferred & What 'Affected by System Real-Time Clock' Means In Java, measuring time is a common task—whether you’re benchmarking code, profiling application performance, scheduling tasks, or tracking elapsed time. Jan 9, 2026 · System. If we at the same time ask System. So you can do this: Nov 1, 2014 · System. currentTimeMillis () provide time-related functionality but serve different purposes and are based on different underlying mechanisms. nanoTime() は、 不連続な時間の変化の影響を受けません。 上記の場合、処理の途中で時刻が変更されても、 total が実際の処理時間を表す値になります。 一方で、あるタイミングの現在時刻を取得するのには不向きです。 例えば、 System. Both are time related functions, i. In contrast, `nanoTime ()` is designed for precision and stability, making it the preferred choice for most timing tasks. currentTimeMillis() right after System. While System. May 6, 2016 · System. to get a time from the system (not the current time ). There are several differences between these two calls, let’s break them down. nanoTime for elapsed time in nanoseconds Instant. 1w次，点赞8次，收藏7次。本文详细比较了System. nanoTime: Precision and Accuracy in Time Measurement When dealing with precise timekeeping in Java, the two dominant methods are System. nanoTime(); long duration = endNanoTime - startNanoTime; logger. nanoTime() is now the preferred method for measuring time over System. Deciding between System. Instead use the System. (Windows 2003 The Java System nanoTime () method returns the current value of the most precise available system timer, in nanoseconds. nanoTime () for accurate game timing? Learn the key differences and best practices for precision. currentTimeMillis () (or, for that matter, System. When the first look only difference between methods can be seen as metrics We would like to show you a description here but the site won’t allow us. nanoTime ()的区别及应用场景。前者适用于获取当前时间，返回从1970年1月1日午夜到现在的毫秒数，但不建议用于计时；后者提供了一个不受NTP影响的稳定递增的纳秒数，适用于需要高精度计时的场景。 Dec 11, 2024 · Dive into the nitty-gritty of Java's time handling! We'll break down the differences between Instant. You’ll want to use currentTimeMillis) for wall-clock time and general event logging, as it’s more efficient at 5-6 CPU cycles but offers millisecond precision. nanoTime() を呼び出して 3761546426118 という値が返ってきて Aug 18, 2024 · System. currentTimeMillis ()为何不是System. Oct 12, 2017 · This means System. nanoTime() does NOT change with the wall clock. now (). nanoTime() 明显非常慢。 具体输出内容我就不放出来了，因为不具有参考价值，大多数生产环境用的是 Linux。 近期热文推荐： Dec 15, 2008 · System. 概述 Java中常用的两个时间测量方法是 System. There are 2 main differences between them. currentTimeMillis表示系统时间,这就导致了的它们的几个差别: System. It is immune to system clock modifications, such as manual adjustments or automatic corrections like daylight saving time transitions or leap seconds. currentTimeMillis() vs System. nanoTime() and store as starting "nano" When I am updating my object's position in my game, should I use System. Nov 24, 2025 · Java时间获取机制解析：currentTimeMillis ()与nanoTime ()的深度对比 摘要：本文深入剖析Java中两种时间获取方式的本质区别。 System. currentTimeMillis( In this example, currentTimeMillis () is used to measure elapsed time in milliseconds, while nanoTime () is used to measure elapsed time in nanoseconds. Fortunately The advantage is high accuracy currentTimeMillis is based on the system time, which means that if you change the system time during the execution of the program, the result will be wrong, and nanoTime is based on the time slice of the CPU to calculate the time and cannot be artificially interfered. Oct 7, 2019 · 总结一下： 1. nanoTime () and System. Accuracy Precision refers to the smallest unit of time that can be measured, while accuracy refers to how close the measurement is to the actual time. The unit of time of the return value is a millisecond, the granularity of the value depends on the underlying operating system and may be larger. currentTimeMillis() simply limits the resolution to milliseconds. Learn the key differences between System. currentTimeMillis及nanoTime原理详解 提取关键问题： 在mac下发现System. currentTimeMillis() and System. nanoTime() returns the elapsed running time of the JVM in nanos, whereas System. nanoTime() gives you a nanosecond-precise time, relative to some arbitrary point. currentTimeMillis两个Java方法的特点及适用场景。System. Note that you can only use this to calculate elapsed time, you cannot use its value as an absolute time. Nov 19, 2016 · According to java. nanoTime ()无法表示当前时间,本质上它是一个随机数字. Jan 17, 2024 · Majority cases elapsed time calculated with nanoTime is higher than elapsed time computed with currentTimeMillis and it's observed from -2 milliseconds to +150 milli seconds. currentTimeMillis ()都是Java中重要的时间测量工具,各有其适用场景。 System. 在同一机器上的不 Java有两个取时间戳的方法： System. nanoTime ()在JDK7和JDK8下输出的值怎么完全不一样 System. currentTimeMillis提供毫秒级精度，适合日常时间记录需求；System. Apr 30, 2011 · Since System. Depending on your JVM, there may be other mechanisms available, but these are generally the two standard ways to time things in Java. nanoTime(): A Dive into Time Measurement 💻⏰Ever wondered about the nuances between System. So Dec 20, 2021 · In the next lines, I will examine two of them that exist in System class, “currentTimeMillis” and “nanoTime”. nanotime is both of these things, Stopwatch just wraps this so you don't have to think about it as much. There are substantial differences between these… Explore the differences between System. nanoTime() - Works great if Android is running, but stops on deep sleep (this is bad). wait(millis), and System. currentTimeMillis() can jump back or forward by 1-2 seconds each time as NTP corrects that drift, making accurate time stamps meaningless. nanoTime提供纳秒级精度，适用于高精度计时，但不适用于获取当前时间。 In this example, currentTimeMillis () is used to measure elapsed time in milliseconds, while nanoTime () is used to measure elapsed time in nanoseconds. currentTimeMillis(), which returns the current time in milliseconds since the Unix epoch, System. 1. nanoTime() 是使用QueryPerformanceCounter / QueryPerformanceFrequency API实现的（如果可用，则返回 currentTimeMillis*10^6)。 QueryPerformanceCounter (QPC) 在运行它的硬件上以不同的方式实现。 Apr 22, 2020 · JVM源码分析之System. Mar 24, 2021 · It appears to be that when you ask System. Stability of the Point of Origin System. g. currentTimeMillis () and System. nanoTime()，它们的使用场景是有区别的，当前网上一些文章对于这两个方法的性能讨论存在一 One quite interesting feature of the difference between System. nanoTime() is a valuable tool provided by the Java standard library that allows developers to measure time with high precision. nanoTime与System. uptimeMillis() and System. nanoTime () 领先一步，其准确性 System. nanoTime ()的值很奇怪，究竟是怎么算出来的 System. currentTimeMillis () returns milliseconds, while System. Java fournit deux méthodes pour chronométrer les opérations, System. nanotime in the same way as System. . currentTimeMillis vs. 👉 Avoid System. I run code on a Windows virtual machine that has heavy time drift. currentTimeMillis() - Good, but not appropriate because it can be changed by the user or by code with setCurrentTimeMillis(long). This article explores the nuances between these methods, addressing their accuracy, precision, and suitability for specific applications. Mar 25, 2013 · 12 In a nutshell, whenever you change system time, the value returned by System. On this page, we look at the differences between System. currentTimeMillis与System. nanoTime이 마이크로초 이내에 실행되는 OS 함수 호출을 포함한다. nanoTime() uptimeMillis() vs nanoTime() System. Apr 12, 2018 · Java provides two methods to time operations, System. 이런 경우 Dec 24, 2024 · Precision vs. nanoTime() is based on a system timer that is independent (*) of wall clock time, I thought I could use changes in the difference between these values to detect system time changes. nanoTime () mainly known as an expensive call, is used to get a more specific value of time. currentTimeMillis() and VM. Dec 9, 2008 · System. This can lead to noticeable discrepancies between their outputs under certain circumstances. But which one should be used in which condition? And which is more efficient? From the first look it might seem that nanoTime () should be used because it gives more precise value of time (in nano seconds, compared to milli seconds that the other method returns). currentTimeMillis is the system time "cleaned up" a bit to have a consistent base. nanoTime()，它们的使用场景是有区别的，当前网上一些文章对于这两个方法的性能讨论存在一些片面的描述，本文希望能给出一个简单的最终答案。Sy… Oct 27, 2025 · 文章浏览阅读1. nanoTime () in Java for precise time measurements. 두 가지 방법은 상당한 차이가 있다. currentTimeMillis() depends on the implementation and on the Operating system and is usually around 10 ms. What functions provide the best fidelity, and what pitfalls exist in common approaches? Feb 2, 2024 · 1. if you change the date, hit a leap second, etc. May 31, 2024 · Java는 시간 값을 측정하는 두 가지 기본 메소드를 제공한다. 在同一机器上的不同JVM上,System. nanoTime()。尽管两者都能用来衡量时间，但它们服务于不同的目的，具有各自的特性。 在这个教程中，我们将探讨这两种方法之间的差异，并理解何时选择使用每一种。 The currentTimeMillis and nanoTime methods are useful for measuring time intervals during execution of an application. May 7, 2025 · System. systemUTC(), you will find that it uses an internal SystemClock class. Oct 27, 2020 · System. currentTimeMillis() is the standard "wall" clock (time and date) expressing milliseconds since the epoch. nanoTime () is more precise. Jan 16, 2021 · What clock does System. Jan 10, 2016 · Here is my modest proposal: When the JVM starts Call System. out. nanoTime is the raw system clock, using the finest resolution available. currentTimeMillis() The method System. currentTimeMillis () 是最真实的可能传递时间，有助于根据操作系统获取时间值。第一个函数以纳秒为单位返回时间值 (有时会给出负值)，而第二个函数以毫秒为单位返回时间值。因此很明显，System. currentTimeMillis () 是最常用的两种。本文将深入探讨这两个API的特点、应用 System. This is the basis for most interval timing such as Thread. currentTimeMillis () have different levels of precision but only have basic "api" support (math operations on long), but are faster to get and smaller to keep in memory. currentTimeMillis() and some use System. currentTimeMillis() for accurate elapsed time measurements, including potential pitfalls and best practices. nanoTime ()和currentTimeMillis ()的使用和区别，包括它们的实现机制、性能差异以及在不同操作系统上的行为。 nanoTime提供了更高的时间精度，适合测量短时间内发生的事件，而currentTimeMillis则与日期和时间相关，适合记录时间跨度。 The granularity of System. To measure a time interval in milliseconds, invoke currentTimeMillis twice, at the beginning and end of the interval, and subtract the first value returned from the second. lang. It is essentially whatever the OS provides. currentTimeMillis() & System. currentTimeMillis () vs System. long duration = endTime - startTime; // Calculate the duration of the loop execution in nanoseconds. currentTimeMillis ()则更适合处理实际日期时间和长时间间隔的计算。 Both System. Understanding the differences between these methods is crucial for selecting the appropriate one for your needs. nanoTime(). nanoTime ()的初始值是在 本JVM实例 启动时"随机"选择的一个数字,随着JVM的运行而变化,System. What functions provide the best fidelity, and what pitfalls exist in common approaches? Jan 5, 2017 · nanoTime (), as the java doc says, is a precision timer. May 30, 2024 · When measuring elapsed time in Java, two common methods are utilized: System. This clock is guaranteed to be monotonic, and is suitable for interval timing when the interval does not span device sleep. System. currentTimeMillis ()表示系统时间 (即UTC). nanoTime (), however, returning nanoseconds, may arguably be better suited to measure deltas (although reportedly a nanoTime () call can be slower than a currentTimeMillis () call - my experiments contradict this: they seem to take exactly the same amount of time). Nov 4, 2025 · System. CurrentTimeMillis returns the current time in milliseconds from the Epoch In Java, when you want to measure elapsed time with minimal overhead, you generally have two options: System. println("//// Test System. The wall clock can be set by the user or the phone network (see setCurrentTimeMillis(long)), so the time may jump backwards or forwards unpredictably. currentTimeMillis () most authentic possible passed time, helps to get the time value based on the operating system. e. Understanding the performance implications of each can help you decide which to use based on your precision requirements. Jul 1, 2022 · Java有两个取时间戳的方法：System. info("Short task duration: " + duration + " nanoseconds"); assertTrue(duration >= 0); } Copy In this еxamplе, thе test mеthod usеs nanoTimе () to capturе thе start and еnd timеs of a short task, providing high prеcision in nanosеconds. When tracking performance in production, we need millisecond resolution. toEpochMilli () and System. Understanding these Jan 9, 2026 · A critical distinction is that `currentTimeMillis ()` is "affected by the system real-time clock," which can lead to unexpected results when measuring elapsed time. currentTimeMillis定义 翻译一下就是： 补充说明 2、System. Sep 25, 2025 · 👉 If you care about measuring durations reliably, use System. This clock stops when the system enters deep sleep (CPU off, display dark, device waiting for external input), but is not affected by clock scaling, idle, or other power saving mechanisms. 즉, 1퍼센트 이내의 측정 정확성을 유지하려면, 매 100마이크로초 이내에 한 번 이상 이 API가 호출되면 곤란하다. nanoTime()，这两个方法都可以用来获取表征当前时间的数值。但是如果不仔细辨别这两个方法的差别和联系，在使用当中也很容易栽跟头。笔者在前不久的工作当中使用System. nanoTime ()和System. currentTimeMillis() returns the current time in milliseconds since the Unix epoch (January 1, 1970, 00:00:00 GMT Feb 15, 2013 · I know that System. Let’s also note that nanoTime (), obviously, returns time in nanoseconds. currentTimeMillis () is NOT A TIMER, it is the "wall clock". nanoTime ()) a function with a guaranteed accuracy on Windows? More specifically, if I run a comparison between a previously-stored time and the current time using those functions, is there any guarantee that those functions will remain accurate? Apr 28, 2019 · JDK提供了两个方法，System. nanoTime (). nanoTime() repeatedly you would be able to get a linear graph with nanosecond resolution. currentTimeMillis()和System. Mais lequel doit être utilisé dans quelle condition ? Et lequel est le plus efficace ? À première vue, il peut sembler que nanoTime () devrait être utilisé car il donne une valeur de temps plus précise (en nanosecondes, par rapport aux millisecondes renvoyées par l’autre Feb 2, 2024 · The System. currentTimeMillis itself is not affected by time zone. nanoTime () et System. nanoTime 的定义 翻译一下就是： 补充说明 对于使用t1-t0< Jul 13, 2020 · The performance of an app has no influence over what happens in deep sleep, so our best options are SystemClock. System. nanoTime ()的初始值是在 本JVM实例 启动时"随机"选择的一个数字,随着JVM的运行而递增（常用来计算实时时间差）,System. 单独获取System. 예를 들어, 최근 윈도 시스템에서는 System. nanoTime ()则是高精度单调计时器，适合性能测量。 Apr 14, 2022 · System. currentTimeMillis is not monotonic and isn't good precision, so gives you unfair benchmarks. ) Jan 2, 2014 · System. currentTimeMillis() or Instant. Dec 4, 2019 · Gettimeofday() is the same Posix call the System. currentTimeMillis() is based on wall clock time and System. nanoTime() and System. nanoTime ()提供了更高的精度和稳定性,特别适合测量短时间间隔和需要高精度的场景。 而System. nanoTime() which returns the current value of the most precise available system timer, in nanoseconds. What does "getting affected by systems real-time clock " mean ? Discover the key differences between System. nanoTime ()的1000000倍 System. 文章浏览阅读986次。本文深入对比分析了Java中System. nanoTime vs currentTimeMillis and Alternatives” When dealing with performance metrics and execution profiling in Java, selecting the appropriate method for measuring elapsed time is paramount for obtaining accurate results. currentTimeMillis () le dará el tiempo transcurrido más preciso posible en milisegundos desde la época, pero System. nanoTime () is designed for high-resolution timing, it incurs more overhead compared to the simpler System. nanoTime() returns a time value whose granularity is a nanosecond; i. Dec 8, 2008 · 精度与Precision我想知道的是，当我在游戏中更新对象的位置时，我应该使用System. 7 I want to add that System. Changing system time will affect System. Use the appropriate method based on your specific timing requirements and precision needs. now()) use fundamentally different clocks. currentTimeMillis() will change accordingly. Jul 30, 2021 · 本文深入探讨了Java中的System. nanoTime() provides a more accurate way to measure elapsed time between two points in a program. currentTimeMillis() returns the number of milliseconds since the start of the Unix epoch – January 1, 1970 UTC. getNanoTimeAdjustment(offset) use the same time source - System. The first three use cases mentioned in the article are ones for which you should NEVER use currentTimeMillis (), but nanoTime () in stead. Jul 17, 2021 · 本文详细解析了Java中System. nldnme acgb oped axzzq nxlzp pvlgf swocys qrys sqeka bkg