A字符串包含B字符串

        String source = "china";
        String target = "INA";

        //contains true 包含
        boolean containsFlag = source.contains(target);
        //indexOf 1 包含 返回子字符串在当前字符串的位置，如果当前字符串不包含子字符串就返回-1
        int indexNum = source.indexOf(target);
        //java.util.regex
        boolean patternFlag = Pattern.compile(Pattern.quote(target), Pattern.CASE_INSENSITIVE).matcher(source).find();
        System.out.println("containsFlag==" + containsFlag);//containsFlag==false
        System.out.println("indexNum==" + indexNum);// indexNum==-1
        System.out.println("patternFlag==" + patternFlag);// patternFlag==true