SpringBoot中使用过滤器

Posted 2020-11-10 精神病人思路广，弱智儿童欢乐多

场景：API的参数都是经过加密的，于是在过滤器中，将获取到的请求的参数先解密再去进行处理

一、实现Filter接口

public class TestFilter implements Filter {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        logger.info("TestFilter init");
    }

    @Override
    public void destroy() {
        logger.info("TestFilter destroy");
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        String servletPath = httpServletRequest.getServletPath();

        String body = HttpHelper.getBodyString(httpServletRequest);
        JSONObject param = JSONObject.parseObject(body);
        if (param == null) {
            logger.info("参数为空");
            return;
        }
        String data = param.getString("data");
        String time = param.getString("time");
        ServletRequestWrapper requestWrapper = new ServletRequestWrapper(httpServletRequest,
                param.toString().getBytes(Charset.forName("UTF-8")));

        // 参数解密 解密过程省略
        //.............
        param.put("data", decryptParam); //将解密后的data取代加密的data
        requestWrapper.setBody(param.toString().getBytes(Charset.forName("UTF-8")));
        
         try {
            // 捕获异常
            chain.doFilter(requestWrapper, response);
        } catch (Exception e) {
            logger.error("", e);
        }
    }

}        

二、设置过滤的接口

 在TestFilter上添加 @WebFilter(filterName = "testFilter", urlPatterns = "/test/*") ，表示在test下的所有接口都经过过滤器

三、启动过滤器

在Application中添加 @ServletComponentScan