能用Java写吗

当然可以，以下是Java版本的实现：

class Solution {
    public int pathSum(TreeNode root, int targetSum) {
        List<Integer> sumList = new ArrayList<>();
        sumList.add(0);
        return dfs(root, sumList, targetSum);
    }

    public int dfs(TreeNode node, List<Integer> sumList, int targetSum) {
        if (node == null) {
            return 0;
        }

        int count = 0;
        int curSum = sumList.get(sumList.size() - 1) + node.val;
        for (int i = 0; i < sumList.size(); i++) {
            if (curSum - sumList.get(i) == targetSum) {
                count++;
            }
        }
        sumList.add(curSum);

        count += dfs(node.left, sumList, targetSum);
        count += dfs(node.right, sumList, targetSum);

        sumList.remove(sumList.size() - 1);
        return count;
    }
}

希望对你有帮助！