Java Scanner学习记录

1. Java.util.Scanner可以用来从键盘获取输入

Scanner.next()  只能读取字符，遇到任何的符合都不会输出

Scanner.nextLine()  会完全按照用户输入的string输出

Example1 for Scanner.next()：

package com.mengdd.junit;
import java.util.*;

public class ScanDemo {
   public static void main(String[] args){
      Scanner scan = new Scanner(System.in);//get data from keyboard
      //get date with nextline
      System.out.println("get date with next: ");
      if (scan.hasNext()){
         String str = scan.next();
         System.out.print(str);
      }
   }
}

run this class and input: I am entering a line to test
after running, the output would be:
get date with next:
I
All strings after I will not be outputed


Example 2 for Scanner.nextLine():

package com.mengdd.junit;

import java.util.Scanner;

/**
 * Created by Sandy.Liu on 2017/6/22.
 */
public class ScanDemo1 {
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        System.out.println("please enter a string");
        if(scan.hasNextLine()){
            String str = scan.nextLine();
            System.out.print(str);
        }
    }
}

run this class and the result will be:

please enter a string
hellow i am entering a line to test
hellow i am entering a line to test
Process finished with exit code 0

 

So nextLine() will get every single character the user inputs even the punctuation