public static String dealRule(final String content, final MockRequest mockRequest) {
        String afterDeal = content;
        String placeHolder = getPlaceholder(content);
        while (Objects.nonNull(placeHolder)) {
            Object generateData = generate(placeHolder, mockRequest);
            if (Objects.equals(generateData, placeHolder)) {
                generateData = ERROR_PARSE;
            }
            String toString = String.valueOf(generateData);
            placeHolder = placeHolder.replaceAll("([$|{}()\\]\\[])", "\\\\$1");
            afterDeal = afterDeal.replaceFirst(placeHolder, toString);
            placeHolder = getPlaceholder(afterDeal);
        }
        return afterDeal;
    }
replace placeholder in content.

@param content response content
@param mockRequest request
@return replace the content after the placeholder.
shenyu-plugin/shenyu-plugin-mock/src/main/java/org/apache/shenyu/plugin/mock/generator/GeneratorFactory.java