如何在Java中使用readline（）方法？ [英] How to use readline() method in Java?

问题描述

我是Java的初学者，我正在阅读通过键盘上的 readLine（）方法为变量赋值的主题。书中给出的程序如下：

I am beginner in Java, and I was reading the topic of giving values to variables through the readLine() method from the keyboard. The program for that is given in the book is as follows:

import java.io.DataInputStream
class Reading
{
    public static void main(String args[])
    {
        DataInputStream in = new DataInputStream(System.in);
        int intnumber=0;
        float floatnumber=0.0f;
        try {
            system.out.println("enter an integer: ");
            intnumber = Integer.parseInt(in.readline());

            system.out.println("enter a float number: ");
            floatnumber = Float.valueOf(in.readline()).floatvalue();
        }

        // Rest of code

我想要提出以下问题：

1. 在以下声明中做了什么？

1. What is done in the following statement?

DataInputStream in = new DataInputStream(System.in);

如果中的是<$的对象c $ c> DataInputStream 那么什么是新的以及上述语句右侧的语句有什么作用？

If in is an object of DataInputStream then what is new and what do the statement on the right-hand side of above statement do?

为什么使用不同的方法将整数值放入intnumber并将float值放入floatnumber？

Why have different methods been used for putting the integer value into intnumber and float value into floatnumber?

推荐答案

我建议您使用 Scanner 而不是 DataInputStream 。 扫描程序专为此目的而设计，并在Java 5中引入。请参阅以下链接以了解如何使用扫描程序。

I advise you to go with Scanner instead of DataInputStream. Scanner is specifically designed for this purpose and introduced in Java 5. See the following links to know how to use Scanner.

• Java文档


• Java教程

• Java Documentation
• Java Tutorial

示例

Scanner s = new Scanner(System.in);
System.out.println(s.nextInt());
System.out.println(s.nextInt());
System.out.println(s.next());
System.out.println(s.next());

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