System.out.println(a.split(b).length);

------解决方案--------------------
LS是什么答案。。 不管怎么显示都是四。。！！

------解决方案--------------------
[code=Java] 
 String a =  "acacacwerwac "; 
 String b =  "ac "; 
 int i = 0; 
 		 
 Pattern p = Pattern.compile(b); 
 Matcher m = p.matcher(a); 
 		 
 while(m.find()){ 
      i++; 
 } 
 System.out.println(i); 
 [/code]

------解决方案--------------------
Java code
public class Test {

    public static void main(String[] args) {
        String a = "acacacwerwac";
        String b = "ac";
        int count = count(a, b);
        System.out.println(count);
    }
    
    private static int count(String src, String find) {
        int count = 0;
        int index = src.indexOf(find); 
        while(index > -1) {
            count++;
            index = src.indexOf(find, index + 1);
        }
        return count;
    }
}