Java 中 ifelse 与 switch 语句的相对性能差异是什么

在Java中，if/else和switch语句是两种常用的条件控制语句。它们都可以根据给定的条件执行不同的代码块。然而，它们在处理不同情况下的性能方面存在一些差异。

java
public class PerformanceComparison {
    public static void main(String[] args) {
        String day = "Monday";
        long startTime, endTime, duration;
        // 使用if/else语句
        startTime = System.nanoTime();
        if (day.equals("Monday")) {
            System.out.println("Start working");
        } else if (day.equals("Tuesday")) {
            System.out.println("Continue working");
        } else if (day.equals("Wednesday")) {
            System.out.println("Take a break");
        } else if (day.equals("Thursday")) {
            System.out.println("Continue working");
        } else if (day.equals("Friday")) {
            System.out.println("Finish working");
        } else {
            System.out.println("Invalid day");
        }
        endTime = System.nanoTime();
        duration = endTime - startTime;
        System.out.println("if/else duration: " + duration + " ns");
        // 使用switch语句
        startTime = System.nanoTime();
        switch (day) {
            case "Monday":
                System.out.println("Start working");
                break;
            case "Tuesday":
                System.out.println("Continue working");
                break;
            case "Wednesday":
                System.out.println("Take a break");
                break;
            case "Thursday":
                System.out.println("Continue working");
                break;
            case "Friday":
                System.out.println("Finish working");
                break;
            default:
                System.out.println("Invalid day");
                break;
        }
        endTime = System.nanoTime();
        duration = endTime - startTime;
        System.out.println("switch duration: " + duration + " ns");
    }
}