Java Program Execution Time Calculation

In Java, you can use either System.currentTimeMillis() or System.nanoTime() method to calculate the running time of a program.

1. Utilize the System.currentTimeMillis() method:

long startTime = System.currentTimeMillis();

// 程序运行代码

long endTime = System.currentTimeMillis();
long totalTime = endTime - startTime;
System.out.println("程序运行时间：" + totalTime + "毫秒");

1. Using the System.nanoTime() method:

long startTime = System.nanoTime();

// 程序运行代码

long endTime = System.nanoTime();
long totalTime = endTime - startTime;
System.out.println("程序运行时间：" + totalTime + "纳秒");

Note: The System.nanoTime() method provides higher precision compared to the System.currentTimeMillis() method, but it is not suitable for calculating wall-clock time. Therefore, when calculating the running time of a program, it is recommended to use the System.currentTimeMillis() method.