自定义request，修改post请求参数

忘是亡心i 2023-02-16 15:30 34阅读 0赞

场景：有时候需要在拦截器层对请求参数进行处理，get请求容易，不谈，现在说下post请求

注意：如果是用json的方式传递，获取数据时是获取的body流，request的body流只能读取一次

步骤：

1.自定义request类

@Slf4j
    public class BodyHttpServletRequestWrapper extends HttpServletRequestWrapper {
    
    
        //存储请求参数--application/x-www-form-urlencoded、form-data方式
        private final List<DataElement> dataList = new ArrayList<>();
    
        public BodyHttpServletRequestWrapper(HttpServletRequest request) {
            super(request);
    
    
            /*
             当需要处理json格式时，在这里通过流获取dataInfo,如果是表单提交，这里通过        
             request.getParameterMap()获取参数并缓存下来，自己举一反三！！
             */
            //req2RawString(request);
            String dataInfo = request.getParameter("data");
            if (StringUtils.isEmpty(dataInfo)){
                return;
            }
    
    
    
            JSONObject jsonObject = JSONObject.parseObject(dataInfo);
            Set<String> keySet = jsonObject.keySet();
            for (String key : keySet) {
                DataElement param = new DataElement();
                param.setKey(key);
                param.setDataInfo(jsonObject.getString(key));
                dataList.add(param);
            }
        }
    
        @Override
        public Enumeration<String> getParameterNames() {
            Set<String> keySet = new HashSet<>();
            dataList.forEach(dataElement -> {
                keySet.add(dataElement.getKey());
            });
            return Collections.enumeration(keySet);
        }
    
        @Override
        @Nullable
        public String[] getParameterValues(String key) {
            String[] parameterValues = new String[1];
            AtomicBoolean haveData = new AtomicBoolean(false);
            dataList.forEach(dataElement -> {
                if (dataElement.getKey().equals(key)) {
                    parameterValues[0] = dataElement.getDataInfo();
                    haveData.set(true);
                }
            });
            if (haveData.get()) {
                return parameterValues;
            } else {
                return null;
            }
        }
    
    /*  public static String req2RawString(HttpServletRequest request) {
            StringBuilder sb = new StringBuilder();
            BufferedReader reader = null;
            try {
                reader = request.getReader();
                String line;
                while ((line = reader.readLine()) != null) {
                    sb.append(line).append('\n');
                }
                if (sb.length() > 1) {
                    sb.replace(sb.length() - 1, sb.length(), "");
                }
            } catch (IOException e) {
                log.info("RequestUtil,IOException:" + e);
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        log.info("RequestUtil,IOException:" + e);
                    }
                }
            }
            String str = sb.toString();
            log.info("Request Result:" + str);
            return str;
    
        }*/
    
    
    /**
    用来存储参数的对象---你可以自定义
    **/
        @Data
        private class DataElement implements Serializable {
    
            private String key;
    
            private String dataInfo;
        }
    }

在控制层进行参数映射时，会调用我们重写的getParameterNames获取所有的key，再通过key调用getParameterValues方法获取对应的值；

2.定义拦截器类，在满足条件的情况下，使用我们自定义的request对象

@Component
    @Slf4j
    public class HttpServletRequestReplacedFilter extends OncePerRequestFilter {
    
        @Override
        protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
    
            //满足条件就使用自定义request对象，否则使用方法参数里的
            String methodType = request.getMethod().toUpperCase();
            if ((("POST".equals(methodType)) || ("DELETE".equals(methodType)) || ("PUT".equals(methodType))) && isBaoWuTransmit(request)) {
                ServletRequest requestWrapper = new BodyHttpServletRequestWrapper(request);
                filterChain.doFilter(requestWrapper, response);
            } else{
                filterChain.doFilter(request, response);
            }
        }
    
        private boolean isBaoWuTransmit(HttpServletRequest request) {
            boolean baoWu = false;
            Enumeration e = request.getHeaderNames();
            while (e.hasMoreElements()) {
                String headerName = (String) e.nextElement();
                if ("appcode".equals(headerName)){
                    baoWu = true;
                }
            }
            return baoWu;
        }

完毕！！！