Java从键盘输入数字，然后将其转换成数值型数据

package com;
import java.io.*;
public class app3_4 {
    public static void main(String [] args) throws IOException
    {
        float num;
        String str;
        BufferedReader buf;
        buf=new BufferedReader(new InputStreamReader(System.in));
        System.out.print("请输入一个实数:");
        str=buf.readLine();
        num=Float.parseFloat(str);
        System.out.println("您输入的数为："+num);
    }
}