使用HttpServletRequestWrapper来修改post请求中的json数据

刺骨的言语ヽ痛彻心扉 2022-04-12 05:14 432阅读 0赞

### 文章目录 ###

*   *   *   *  过滤的效果：
             *  具体的实现代码：

公司里最近在做一个新的项目，项目中所有的请求都是这样的一个格式。  
![在这里插入图片描述][20181201160406466.jpg]  
因为version版本号在业务里并没有用到，只是一个验证依据，所以就想把它过滤掉。

#### 过滤的效果： ####

过滤前
    { 
    "version" : "11111111",
    "data": { 
       "heartbeat_time": 1468471315134
    }
    }
    过滤后
    { "heartbeat_time":1468471315134}

#### 具体的实现代码： ####

1.自定义一个过滤器

@Component
    @ServletComponentScan
    @WebFilter(urlPatterns = "/north/*", filterName = "httpFilter")//此处的url根据实际情况而定
    public class HttpReplaceFilter implements Filter { 
        private static final Set<String> ALLOW_PATHS = new HashSet<>(Arrays.asList("/serviceName"));
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException { 
            String path = ((HttpServletRequest)request).getRequestURI().substring(((HttpServletRequest) request).getContextPath().length());
            //如果是在ALLOW_PATHS的集合中，那么就允许这种请求直接通过
            if (ALLOW_PATHS.contains(path)){ 
                filterChain.doFilter(request, response);
            }
            //HttpServletRequest没有提供相关的set方法来修改body，所以需要用修饰类
            ServletRequest requestWrapper = new BodyRequestWrapper((HttpServletRequest) request);
    
            filterChain.doFilter(requestWrapper, response);
        }
    
        @Override
        public void destroy() { 
    
        }
    }

2.自定义一个Http请求的修饰类

public class BodyRequestWrapper extends HttpServletRequestWrapper { 
    
        private byte[] body;
        public BodyRequestWrapper(HttpServletRequest request) throws IOException { 
            super(request);
            StreamUtil.readBytes(request.getReader(), "utf-8");
            //由于request并没有提供现成的获取json字符串的方法，所以我们需要将body中的流转为字符串
            String json = new String(StreamUtil.readBytes(request.getReader(), "utf-8"));
            body = getData(json).getBytes();
        }
    
        @Override
        public BufferedReader getReader() throws IOException { 
            return new BufferedReader(new InputStreamReader(getInputStream()));
        }
    
        /**
         * 在使用@RequestBody注解的时候，其实框架是调用了getInputStream()方法，所以我们要重写这个方法
         * @return
         * @throws IOException
         */
        @Override
        public ServletInputStream getInputStream() throws IOException { 
            final ByteArrayInputStream bais = new ByteArrayInputStream(body);
    
            return new ServletInputStream() { 
                @Override
                public boolean isFinished() { 
                    return false;
                }
    
                @Override
                public boolean isReady() { 
                    return false;
                }
    
                @Override
                public void setReadListener(ReadListener readListener) { 
    
                }
    
                @Override
                public int read() throws IOException { 
                    return bais.read();
                }
            };
        }
    
        private String getData(String json){ 
            if (!json.contains("\"data\"")){ 
                return "";
            }
            ObjectMapper mapper = new ObjectMapper();
            String data = null;
            try { 
                JsonNode jsonNode = mapper.readTree(json);
                data = jsonNode.get("data").toString();
            } catch (IOException e) { 
                e.printStackTrace();
            }
    
            return data;
        }
    }

以上代码就可以实现将json数据过滤掉了

框架是springboot，还有用到了joda-io依赖包

[20181201160406466.jpg]: /images/20220412/2e1e395d03a541649df99b1019038603.png