樸素的模式匹配演算法實現Java中indexOf(String str, int fromIndex);
即字主字串中查詢目標字串並返回指標地址；

public class StringUtils {

   public static int indext(String src, String target) {
        return indext(src,target,0);
    }

    public static int indext(String src, String target, int fromIndex) {
        return indext(src.toCharArray(), src.length(), target.toCharArray(), target.length(), fromIndex);
    }

    //樸素模式匹配演算法
 

    static int indext(char[] s, int slen, char[] t, int tlen, int fromIndex) {
        if (fromIndex < 0) {
            fromIndex = 0;
        }
        if (tlen == 0) {
            return fromIndex;
        }
        if (slen == 0) {
            return -1;
        }
        int i = fromIndex;
        int
 
 j = 0;
        while (i <= slen && j <= tlen) {
            /*  cycle compare */
            if (s[i] == t[j]) {
                ++i;
                ++j;
            } else {
                /*  point back last position */
                i = i - j + 1;
                j = 0;
            }
        }
        if
 
 (j > tlen) {
            /*  found target string retun first index position*/
            return i - j;
        } else {
             /* can't find target  string and retun -1 */
            return -1;
        }
    }
}