int string2Int(String s) throws NumberFormatException { if(s==null) throw new NumberFormatException(); int index=1; int result=0; int len=s.length(); char zero='0'; for(int i=len;i>0;i--) { char c=s.charAt(i-1); int digit=c-zero; if(digit<0||digit>9) { throw new NumberFormatException(); } result = result+ digit*index; index = index*10; } return result; }
{
if(s==null)
throw new NumberFormatException();
int index=1;
int result=0;
int len=s.length();
char zero='0';
for(int i=len;i>0;i--)
{
char c=s.charAt(i-1);
int digit=c-zero;
if(digit<0||digit>9)
{
throw new NumberFormatException(); }
result = result+ digit*index;
index = index*10;
}
return result;
}
String data;
个位数=data.charAt(data.length()-1);
10位数=data.charAt(data.length()-1);
...位数=data.charAt(0);正常情况下data.charAt(n)应该 大于等于'0',小于等于'9',否则不是正确的数字