java从控制台读取字符串

Today we will look into different ways to read string from console in java.

今天，我们将研究从Java中的控制台读取字符串的不同方法。

从控制台读取Java字符串 (Java Read String from Console)

We can use below classes to read input from console.

我们可以使用以下类从控制台读取输入。

1. BufferedReader缓冲读取器
2. Scanner扫描器

使用BufferedReader从控制台读取Java字符串 (Java Read String from Console using BufferedReader)

BufferedReader class is from Java IO package. We can use BufferedReader to read text from a character-input stream. Below is a simple program to read string data from console and print it in lower case.

BufferedReader类来自Java IO包。 我们可以使用BufferedReader从字符输入流中读取文本。 下面是一个简单的程序，可从控制台读取字符串数据并以小写形式打印。

package com.journaldev.examples;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;public class JavaReadFromConsoleBufferedReader {public static void main(String[] args) throws IOException {BufferedReader br = new BufferedReader(new InputStreamReader(System.in));System.out.println("Enter Input String:");String input = br.readLine();br.close();System.out.println("Input String in Lower Case = " + new String(input).toLowerCase());}
}

Below is the output produced by one sample run of above program.

下面是上述程序的一个示例运行所产生的输出。

Enter Input String:
Java Developer
Input String in Lower Case = java developer

使用扫描仪从控制台读取Java (Java Read from Console using Scanner)

If you notice above code, BufferedReader is not flexible and has very limited options. We can only read input data as String. That’s why Scanner class was introduced in Java 1.5 to read from console with many options.

如果您注意到上述代码，则BufferedReader并不灵活，并且选项非常有限。 我们只能将输入数据读取为String。 这就是为什么Java 1.5中引入了Scanner类以从控制台读取很多选项的原因。

We can use Scanner class to read as String, primitive data types such as int, long etc. We can also read input numbers in different bases such as binary and read it to integer. Let’s have a look at how to use Scanner class to read input data from console.

我们可以使用Scanner类将String，原始数据类型（如int，long等）读取为String。我们还可以读取不同基数的输入数字（如二进制）并将其读取为整数。 让我们看一下如何使用Scanner类从控制台读取输入数据。

package com.journaldev.examples;import java.util.Scanner;public class JavaReadStringFromConsoleScanner {public static void main(String[] args) {Scanner sc = new Scanner(System.in);System.out.println("Please enter a String:");String input = sc.nextLine();System.out.println("Input String in Upper Case = " + input.toUpperCase());System.out.println("Please enter a integer in Binary Format:");int i = sc.nextInt(2);System.out.println("Number in Decimal = " + i);sc.close();}}

Below is the output produced by above program when executed and input is provided in Console.

下面是上述程序在执行时产生的输出，并且在Console中提供了输入。

Please enter a String:
Java Read String using Scanner Class
Input String in Upper Case = JAVA READ STRING USING SCANNER CLASS
Please enter a integer in Binary Format:
110110
Number in Decimal = 54

That’s all for java read from console program or how to read string from console in java.

这就是从控制台程序中读取Java或如何从Java中的控制台读取字符串的全部内容。

翻译自: https://www.journaldev.com/18356/java-read-string-console

java从控制台读取字符串