public int indexOf(String str)Returns the index within this string of the first occurrence of the specified substring. The integer returned is the smallest value k such that:
this.startsWith(str, k)
is true. Parameters:
str - any string.
Returns:
if the string argument occurs as a substring within this object, then the index of the first character of the first such substring is returned; if it does not occur as a substring, -1 is returned
this.startsWith(str, k)
is true. Parameters:
str - any string.
Returns:
if the string argument occurs as a substring within this object, then the index of the first character of the first such substring is returned; if it does not occur as a substring, -1 is returned
if(str.indexOf("b")!=-1){
System.out.println("Do not exist");
}
含有
else
不含有