为什么我的Java StringTokenizer读取空白？

Question

I wrote this program that should only break down the string when there is greater than sign or a colon. When I enter for example "cars:ford> chevy" , the output gives me the space between the > and "chevy" and then the word "chevy. How do I prevent it from giving me that white space? All I want is the word , here is my code.

import java.util.Scanner;
import java.util.StringTokenizer;

public class wp{
    public static void main(String[]args){

        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter words");

        String ingredients = keyboard.nextLine();

        StringTokenizer str = new StringTokenizer(ingredients,">:");

        while(str.hasMoreTokens()){
            System.out.println(str.nextToken());
        }

    }
}

Answer 1

As the space is part of the input, it is valid that the tokenizer returns it (think of situations where you want to react to the space).

So all you need to do is postprocess your split results eg:

public class Main {

    public static void main(String[] args) {

        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter words");

        String ingredients = keyboard.nextLine();

        StringTokenizer str = new StringTokenizer(ingredients, ">:");

        while (str.hasMoreTokens()) {
            String nextToken = str.nextToken();
            String trimmed = nextToken.trim();
            System.out.println(trimmed);
        }

    }
}

Answer 2

Answer to trim is ok also, but on line

StringTokenizer str = new StringTokenizer(ingredients, ">:");

you specified delimiters as characters '>' and ':' , you can simply add space there too. It depends what your requirements are. If you want for string "cars:ford> chevy 123" to have 4 tokens, this is what you have to do...

So change it to

StringTokenizer str = new StringTokenizer(ingredients, ">: ");

Answer 3

您可以使用String类的trim()方法删除所有之前和之后的空格： str.nextToken().trim() 。