Java 字符终端上获取输入三种方式

package com.srie.chapter01;

import java.io.BufferedReader;
import java.io.Console;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;

public class TestCalc {

    public static void main(String[] args) throws Exception {
        
        readBySystem();
        readByScanner();
        readByConsole();
    }

    private static void readByConsole() {
        System.out.println("read by console");
        Console console = System.console();
        if(console == null){
            System.out.println("console is null!");
        }else{
            String readLine = console.readLine();
            System.out.println(readLine);
        }
    }

    private static void readBySystem() throws IOException {
        System.out.println("read by system.in");
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        String readLine = bufferedReader.readLine();
        System.out.println(readLine);
    }

    private static void readByScanner() {
        System.out.println("read by scanner:");
        Scanner scanner = new Scanner(System.in);
        String nextLine = scanner.nextLine();
        System.out.println(nextLine);
    }

}