如何显示字符串在另一个字符串中出现的次数

System.out.println(a.split(b).length);
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LS是什么答案。。 不管怎么显示都是四。。！！
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[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]
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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;    }}