测试

//public class Stringdemo
//{public static void main (String args[]){
// String ste="hello";
//  char st = ste.charAt(0);//取出指定索引的字符
//  System.out.println(st);
//  }
//}


/* public class Stringdemo
{public static void main(String args[]){
   String ste="helloworld";
   char [ ] deat = ste.toCharArray(); 将字符串变成字符数组
   for (int x=0;x<deat.length ; x++){
   //System.out.println(deat[x]+",");
    deat[x] -=32;
   }
  System.out.println(new String(deat) ); 将所有字符数组变成String
  System.out.println(new String(deat,5,4)); 将部分字符数组变成String
   }
}*/



public class Stringdemo
{public static void main(String args[]){
   String ste="84546464";
if (isAsa(ste))
{System.out.println("是数字");
}
else {
  System.out.println("不是数字");
  }
}
public static boolean isAsa(String temp){
   char [ ] ch = temp.toCharArray();//将字符串转换为数组
   for (int x=0; x<ch.length; x++)
   {if (ch[x] < '0' || ch[x] > '9')//因为不是String类型 所有不能使用""
   {return false;
   }
   
   }
   return true;
   }
}

（ 字符与字符串 ）2016-09-0118:05:00