Guide to using StopWatch timing tool in Java

In Java programming,StopWatchIt is a very useful tool, especially when it is necessary to make precise time measurements of a certain part of the program.

1. What is StopWatch

StopWatchIt is usually used to measure the time it takes for a piece of code to execute. It can accurately record the start time and end time, and calculate the time difference between this. In Java,StopWatchIt is not the most basic class in the Java standard library, but like(In Spring frameworkStopWatch) Such implementations are very popular.

Conceptually, it's like a high-precision stopwatch. You can start timing in a key part of the code (like pressing the start button of the stopwatch), then stop timing after that part of the code is executed (press the stop button), and finally get the time it takes for the code to execute.

2. How to use (taking StopWatch in Spring framework as an example)

1. Introduce dependencies

If you are using the Maven project, you need toIntroducing the core dependencies of Spring (becauseStopWatchIn Spring Core Library):

<dependency>
    <groupId></groupId>
    <artifactId>spring-core</artifactId>
    <version>{spring - version}</version>
</dependency>

2. Code example

import ;
public class StopWatchExample {
    public static void main(String[] args) {
        // Create a StopWatch instance        StopWatch stopWatch = new StopWatch();
        // Start timing        ();
        // Here is the code block to be timed, such as a simple loop        for (int i = 0; i &lt; 1000000; i++) {
            // Here it can be any simple operation, such as mathematical calculation            (i);
        }
        // Stop timing        ();
        // Time spent on output        ("The time it takes to execute this code block is: " + () + "Milliseconds");
        // You can also time it in stages        ();// Reset StopWatch for use again        ();
        // The first stage code        for (int i = 0; i &lt; 500000; i++) {
            (i, 2);
        }
        ();
        ("The time spent in the first phase is: " + () + "Milliseconds");
        ();
        // Code for the second stage        for (int i = 500000; i &lt; 1000000; i++) {
            (i, 3);
        }
        ();
        ("The time spent in the second phase is: " + () + "Milliseconds");
        ("Total execution time (sum of two stages): " + () + "Milliseconds");
    }
}

First, we create an instance of StopWatch: StopWatch stopWatch = new StopWatch();. It's like getting a new stopwatch.
Then, start the timing by (); At this time, it is equivalent to pressing the start button of the stopwatch to start recording the time.
Next, we have a loop code block, which is the part where we want to measure execution time. In this example, simple mathematical calculations are performed inside the loop.
After that, stop the timing by ();, it is like pressing the stop button of the stopwatch.
Use() to get the time it takes from start to stop the entire process and print it out. This time is in milliseconds.

We also show the functionality of phased timing:

Reset StopWatch with();, which can restart timing and clear previous timing data.
At each stage, we can calculate the time separately. For example, () can get the time taken for the last task (i.e. between the last start-stop).

Boundary processing:

When using StopWatch, if you forget to call start and call stop, an exception will be thrown. So make sure the correct order of start and stop is called.
In a multi-threaded environment, if multiple threads operate the same StopWatch instance at the same time, the results may be inaccurate. If there is such a requirement, you need to consider locking or creating a StopWatch instance for each thread separately.

This is the article about the in-depth analysis and usage guide of StopWatch timing tools in Java. For more related content on Java StopWatch usage, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!