public class Test{
public static void main(String[] args){
String str1 = "1234";
String str2 = "123ab";
System.out.println(isNumber(str1));
System.out.println(isNumber(str2));
}
public static boolean isNumber(String str){
//String->char[]
char[] a=str.toCharArray();//先将字符串转为字符数组
for(int i = 0;i<a.length;i++){//通过遍历来判断字符数组中的每一个元素是否为数字
char b = a[i];
if(b<'0'||b>'9'){
return false;
}
}
return true;
}
}