Request Body数据读取

拦截器要读取request body数据的话需要注意一个问题，一旦拦截器把数据流从request读取出来后，后区的接口层就拿不到数据了，因为流是一次性的，那么要解决这个问题，我们就需要在拦截器取出流拿到数据后重新将数据放回流，这样后面的接口层就能正常获取到数据了

下面放出代码实现：

@Component
@Order(10000)
@WebFilter(filterName = "HttpServletRequestFilter", urlPatterns = "/")
public class HttpServletRequestFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig){

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        String path = "";
        if (servletRequest instanceof HttpServletRequest && servletRequest.getInputStream() != null) {
            path = ((HttpServletRequest) servletRequest).getRequestURI();
            if(path.equals( "/health" )){
                filterChain.doFilter(servletRequest, servletResponse);
                return;
            }
            //获取请求中的流如何，将取出来的字符串，再次转换成流，然后把它放入到新request对象中
            requestWrapper = new RequestWrapper((HttpServletRequest) servletRequest);
        }
        //在chain.doFiler方法中传递新的request对象
        if (null == requestWrapper) {
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            filterChain.doFilter(requestWrapper, servletResponse);
        }
        if(servletResponse.getOutputStream() != null){
            RequestWrapper.transmittableThreadLocal.remove();
        }
    }

    @Override
    public void destroy() {

    }
}

/**
* <p>Title:HttpServletRequest 包装器</p>
* <p>Description:
 * 解决: request.getInputStream()只能读取一次的问题
 * 目标: 流可重复读
 * </p>
* @author QIQI
* @params
* @return
* @throws
* @date 2020/11/16 14:24
*/
public class RequestWrapper extends HttpServletRequestWrapper {
    public static final ThreadLocal<String> transmittableThreadLocal = new TransmittableThreadLocal<>();
    /**
     * 请求体
     */
    private String mBody;

    public RequestWrapper(HttpServletRequest request) {
        super(request);
        // 将body数据存储起来
        mBody = getBody(request);
        transmittableThreadLocal.set(mBody);
    }

    /**
     * 获取请求体
     *
     * @param request 请求
     * @return 请求体
     */
    private String getBody(HttpServletRequest request) {
        return getBodyString(request);
    }

    /**
     * 获取请求体
     *
     * @return 请求体
     */
    public String getBody() {
        return mBody;
    }

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        // 创建字节数组输入流
        final ByteArrayInputStream bais = new ByteArrayInputStream(mBody.getBytes( StandardCharsets.UTF_8));

        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();
            }
        };
    }

    /**
     * 获取请求Body
     *
     * @param request
     * @return
     */
    private String getBodyString(ServletRequest request) {
        StringBuilder sb = new StringBuilder();
        InputStream inputStream = null;
        BufferedReader reader = null;
        try {
            inputStream = request.getInputStream();
            reader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
            String line = "";
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }
}