java 正则表达式匹配字符串

private static List<String> getImage(String str){
        List<String> tmp=new ArrayList<String>();
        String regex="<img src=\"([^\"]+?)\" />";
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(str);
        System.out.println(str);
        while(matcher.find()){

            tmp.add(matcher.group(1).toString());

        }
        return tmp;
    }