Java 開発: コードのパフォーマンス テストとパフォーマンスの最適化を実行する方法

public class ObjectPool {
    private List<Object> pool;

    public ObjectPool() {
        pool = new ArrayList<>();
        // 初始化对象池
        for (int i = 0; i < 50; i++) {
            pool.add(new Object());
        }
    }

    public Object getObject() {
        if (pool.isEmpty()) {
            // 如果对象池为空，创建新的对象
            return new Object();
        } else {
            // 从对象池中获取对象
            return pool.remove(pool.size() - 1);
        }
    }

    public void releaseObject(Object object) {
        // 将对象放回对象池
        pool.add(object);
    }
}

public class PerformanceOptimization {
    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();
        // 添加元素
        for (int i = 0; i < 1000000; i++) {
            list.add(i);
        }

        // 使用HashMap查找元素
        Map<Integer, Integer> map = new HashMap<>();
        for (int i = 0; i < list.size(); i++) {
            map.put(list.get(i), list.get(i));
        }

        // 查找元素
        int target = 500000;
        if (map.containsKey(target)) {
            System.out.println("找到了目标元素：" + target);
        } else {
            System.out.println("未找到目标元素：" + target);
        }
    }
}

public class BubbleSort {
    public static void main(String[] args) {
        int[] arr = {5, 2, 8, 9, 1};
        bubbleSort(arr);
        for (int num : arr) {
            System.out.print(num + " ");
        }
    }

    public static void bubbleSort(int[] arr) {
        int n = arr.length;
        for (int i = 0; i < n - 1; i++) {
            for (int j = 0; j < n - i - 1; j++) {
                if (arr[j] > arr[j + 1]) {
                    // 交换元素
                    int temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
        }
    }
}

Benchmark            Mode  Cnt  Score   Error  Units
BubbleSortTest.test  avgt    5  0.045 ± 0.002  ms/op

public class QuickSort {
    public static void main(String[] args) {
        int[] arr = {5, 2, 8, 9, 1};
        quickSort(arr, 0, arr.length - 1);
        for (int num : arr) {
            System.out.print(num + " ");
        }
    }

    public static void quickSort(int[] arr, int low, int high) {
        if (low < high) {
            int pivot = partition(arr, low, high);
            quickSort(arr, low, pivot - 1);
            quickSort(arr, pivot + 1, high);
        }
    }

    public static int partition(int[] arr, int low, int high) {
        int pivot = arr[high];
        int i = low - 1;
        for (int j = low; j < high; j++) {
            if (arr[j] < pivot) {
                i++;
                // 交换元素
                int temp = arr[i];
                arr[i] = arr[j];
                arr[j] = temp;
            }
        }
        // 交换元素
        int temp = arr[i + 1];
        arr[i + 1] = arr[high];
        arr[high] = temp;
        return i + 1;
    }
}

Benchmark             Mode  Cnt  Score    Error  Units
QuickSortTest.test    avgt    5  0.001 ±  0.001  ms/op