springmvc中 配置过滤器导致的post请求参数丢失问题

问题描述:

​ 项目新增加功能,需要添加接口调用的入参验签,新增添加拦截器,并且配置了自定义BodyReaderHttpServletRequestWrapper实现流的复用,在不同的springboot版本中产生以下问题:

接口发送前提:POST multipart/form-data 请求

springboot 1.5.3.RELEASE 中发现过滤器中无法获取parameters 而controller层能获取到

springboot 2.2.5.RELEASE 中发现过滤器能获取parameters 而controller层不能获取到

//过滤器代码
 @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        String contentType = httpRequest.getContentType();
        if (request instanceof HttpServletRequest) {
                // 将请求对象包装为 可重复读取流的请求对象。注意：构造好了，但是需要在拦截器中获取
                /** 也可以使用 ContentCachingRequestWrapper **/
                requestWrapper= new  ContentCachingRequestWrapper((HttpServletRequest) request);
            //自定义的wapper
//                requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
            }
            chain.doFilter(requestWrapper, response);
        }else{
			chain.doFilter(request, response);
    }
        return;
    }

public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
	private byte[] requestBody = null;// 用于将流保存下来
	public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
		super(request);
        //注意此处已经调过inputStream 
		requestBody = StreamUtils.copyToByteArray(request.getInputStream());
	}
	@Override
	public ServletInputStream getInputStream() throws IOException {
		final ByteArrayInputStream bais = new ByteArrayInputStream(requestBody);
		return new ServletInputStream() {
			@Override
			public int read() throws IOException {
				return bais.read();
			}
			@Override
			public boolean isFinished() {
				return false;
			}
			@Override
			public boolean isReady() {
				return false;
			}
			@Override
			public void setReadListener(ReadListener readListener) {
			}
		};
	}
	@Override
	public BufferedReader getReader() throws IOException {
		return new BufferedReader(new InputStreamReader(getInputStream()));
	}
}

根本原因 request的getInputStream()/getReader() 与 getParameter() 的冲突问题

//代码定位
//查看request类的方法
   @Override
    public String getParameter(String name) {
        if (!parametersParsed) {   
            //进入
            parseParameters();
        }
        return coyoteRequest.getParameters().getParameter(name);
    }

 //问题在此处 如果已经调用过getInputStream/getReader 此次会直接返回
 if (usingInputStream || usingReader) {
                success = true;
                return;
            }
//此处如此设计是因为Servlet3.1有相关规范如下图

springboot版本不同 引起的结果不同:

在类WebMvcAutoConfiguration中有所不同

​ 新版本中

	@Bean
	@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)
	@ConditionalOnProperty(prefix = "spring.mvc.hiddenmethod.filter", name = "enabled", matchIfMissing = false)
	public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
		return new OrderedHiddenHttpMethodFilter();
	}

​ 老版本中

@Bean
	@ConditionalOnMissingBean(HiddenHttpMethodFilter.class)
	public OrderedHiddenHttpMethodFilter hiddenHttpMethodFilter() {
		return new OrderedHiddenHttpMethodFilter();
	}

老版本中生效 而新版本不生效

@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {
		HttpServletRequest requestToUse = request;
		if ("POST".equals(request.getMethod()) && request.getAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE) == null) {
			String paramValue = request.getParameter(this.methodParam);
			if (StringUtils.hasLength(paramValue)) {
				String method = paramValue.toUpperCase(Locale.ENGLISH);
				if (ALLOWED_METHODS.contains(method)) {
					requestToUse = new HttpMethodRequestWrapper(request, method);
				}
			}
		}
		filterChain.doFilter(requestToUse, response);
	}

spring 2.2.5解决办法:

    /** 第一种 先调用获取参数  解决getParameterNames 和getInputStream 冲突问题 **/
        Map<String, String[]> parameterMap = request.getParameterMap();
        log.info("请求参数:{}", JSON.toJSONString(parameterMap));
        if (request instanceof HttpServletRequest) {
            // 将请求对象包装为 可重复读取流的请求对象。注意：构造好了，但是需要在拦截器中获取
            requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
            chain.doFilter(requestWrapper, response);
        }else {
            chain.doFilter(request, response);
        }
        return;

参考文档

Request重复读取流 - 简书 (jianshu.com)

记一次getParameter()获取不到参数问题的排查 - litter-chick - 博客园 (cnblogs.com)

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