2.多行输入

输入一行，然后按回车键结束此行的输入

        Scanner in = new Scanner(System.in);
        String line = in.nextLine();
        Scanner in2 = new Scanner(line);
        //输入第一行
        while (in2.hasNextInt()) {
            exp1.add(in2.nextInt());
        }
        String line1 = in.nextLine();
        Scanner in3 = new Scanner(line1);
        //输入第二行
        while (in3.hasNextInt()) {
            exp2.add(in3.nextInt());
        }