Scanner

Scanner

1.scanner.next

    //创建一个扫描器对象，用于接受键盘数据
    Scanner scanner = new Scanner(System.in);

    System.out.println("使用next方式接受:");

    //判断用户有没有输入字符串
    if (scanner.hasNext()){
        String str = scanner.next();
        System.out.println("输出的内容为:"+str);
    }

    //凡是属于IO流的类如果不关闭会一直占用资源要养成好习惯用完关掉
    scanner.close();

2.scanner.nextLine

    //从键盘接收数据
    Scanner scanner = new Scanner(System.in);
    System.out.println("使用nextLine方式接收:");

    //判断是否还有输入
    if (scanner.hasNextLine()){
        String str = scanner.nextLine();
        System.out.println("输出的内容为:"+str);
    }
    scanner.close();

3.简化

    Scanner scanner = new Scanner(System.in);
    System.out.println("请输入数据:");
    String str = scanner.nextLine();
    System.out.println("输出的内容为:"+str);
    scanner.close();

4.输入int与float

    Scanner scanner = new Scanner(System.in);

    //从键盘接收数据
    int i = 0;
    float f = 0.5f;

    System.out.println("请输入整数:");

    if (scanner.hasNextInt()){
        i = scanner.nextInt();
        System.out.println("整数数据:"+i);
    }else {
        System.out.println("输入的不是整数数据!");
    }

    System.out.println("请输入小数:");

    if (scanner.hasNextFloat()){
        f = scanner.nextFloat();
        System.out.println("小数数据:"+f);
    }else {
        System.out.println("输入的不是小数数据!");
    }

    scanner.close();

5.多数字求和、平均数

    Scanner scanner = new Scanner(System.in);

    //从键盘接收数据
    int i = 0;
    float f = 0.5f;

    System.out.println("请输入整数:");

    if (scanner.hasNextInt()){
        i = scanner.nextInt();
        System.out.println("整数数据:"+i);
    }else {
        System.out.println("输入的不是整数数据!");
    }

    System.out.println("请输入小数:");

    if (scanner.hasNextFloat()){
        f = scanner.nextFloat();
        System.out.println("小数数据:"+f);
    }else {
        System.out.println("输入的不是小数数据!");
    }

    scanner.close();