How to input in java?

During the development of Java programs, it is common to need to obtain input values ​​from the keyboard. Java does not provide a function to obtain input, which does not mean that we are helpless when encountering this situation. Let's take a look at how to input in Java.

Several methods will be listed below:

Method 1: Receive a character from the console and print it out

import java.io.*;
public static void main(String [] args) throws IOException{ 
         System.out.print("Enter a Char:"); 
         char i = (char) System.in.read(); 
         System.out.println("your char is :"+i); 
}

Although this method achieves obtaining the input characters from the keyboard, System.in.read() can only obtain one character . At the same time, the type of the incoming variable can only be char. When we When we input a number and hope to get an integer variable, we have to modify the variable type, which is more troublesome.

Method 2: Receive a string from the console and print it out. In this question, we need to use the BufferedReader class and the InputStreamReader class

import java.io.*;
public static void main(String [] args) throws IOException{ 
           BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); 
           String str = null; 
           System.out.println("Enter your value:"); 
           str = br.readLine(); 
           System.out.println("your value is :"+str); 
}

so that we can get the string we input.

Method 3: I think this method is the simplest and most powerful, which is to use the Scanner class

java.util.Scanner is a new feature of Java5, we can use the Scanner class to Get user input.

import java.util.Scanner;
public static void main(String [] args) { 
         Scanner sc = new Scanner(System.in); 
         System.out.println("请输入你的姓名："); 
         String name = sc.nextLine(); 
         System.out.println("请输入你的年龄："); 
         int age = sc.nextInt(); 
         System.out.println("请输入你的工资："); 
         float salary = sc.nextFloat(); 
         System.out.println("你的信息如下："); 
         System.out.println("姓名："+name+"\n"+"年龄："+age+"\n"+"工资："+salary); 
}

This code has shown that the Scanner class, whether it is a string, integer data or float type variable, only needs to make a small change to achieve the function! Undoubtedly he is the most powerful!

For more java knowledge, please pay attention to java basic tutorial.

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