如何在SpringBoot的Request中多次读取InputStream

最近一个项目需要在请求中效验签名 签名的参数用到了请求的数据
如果请求的数据是 application/x-www-form-urlencoded 的格式那么没问题
但是如果请求的数据是 application/json 则用到了 @RequestBody 中的数据
但是由于 InputStream 只能取一次数据
最后导致 Controller 中取不到数据

解决方案

• 新建一个 SignHttpServletRequestWrapper 包装请求

  package com.sixi.enquiry.interceptor;
  
  import java.io.BufferedInputStream;
  import java.io.ByteArrayInputStream;
  import java.io.ByteArrayOutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import javax.servlet.ReadListener;
  import javax.servlet.ServletInputStream;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletRequestWrapper;
  
  /**
   * Created with IntelliJ IDEA
   *
   * @author 喵♂呜
   * Created on 2017/12/20 19:01.
   */
  public class SignHttpServletRequestWrapper extends HttpServletRequestWrapper {
      private final byte[] body;
  
      /**
       * Constructs a request object wrapping the given request.
       *
       * @param request
       *         The request to wrap
       * @throws IllegalArgumentException
       *         if the request is null
       */
      public SignHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
          super(request);
          body = readBytes(request.getInputStream());
      }
  
      @Override
      public ServletInputStream getInputStream() throws IOException {
          final ByteArrayInputStream bais = new ByteArrayInputStream(body);
          return new ServletInputStream() {
  
              @Override
              public int read() throws IOException {
                  return bais.read();
              }
  
              @Override
              public boolean isFinished() {
                  return bais.available() == 0;
              }
  
              @Override
              public boolean isReady() {
                  return false;
              }
  
              @Override
              public void setReadListener(ReadListener arg0) {
              }
          };
      }
  
      private byte[] readBytes(InputStream in) throws IOException {
          int buffSize = 1024;
          try (BufferedInputStream bis = new BufferedInputStream(in); ByteArrayOutputStream out = new ByteArrayOutputStream(buffSize)) {
              byte[] temp = new byte[buffSize];
              int size;
              while ((size = bis.read(temp)) != -1) {
                  out.write(temp, 0, size);
              }
              return out.toByteArray();
          }
      }
  }

• 添加一个 SignFilter 过滤器用来封装请求

  package com.sixi.enquiry.interceptor;
  
  import java.io.IOException;
  
  import javax.servlet.Filter;
  import javax.servlet.FilterChain;
  import javax.servlet.FilterConfig;
  import javax.servlet.ServletException;
  import javax.servlet.ServletRequest;
  import javax.servlet.ServletResponse;
  import javax.servlet.http.HttpServletRequest;
  
  import org.springframework.http.HttpMethod;
  import org.springframework.http.MediaType;
  
  /**
   * Created with IntelliJ IDEA
   *
   * @author 喵♂呜
   * Created on 2017/12/20 18:58.
   */
  public class SignFilter implements Filter {
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {}
  
      @Override
      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
          if (request instanceof HttpServletRequest) {
              HttpServletRequest httpServletRequest = (HttpServletRequest) request;
              // 只处理POST并且ContentType是JSON的请求 这里根据业务情况自行修改
              if (HttpMethod.POST.matches(httpServletRequest.getMethod().toUpperCase()) &&
                  httpServletRequest.getContentType().contains(MediaType.APPLICATION_JSON_VALUE)) {
                  ServletRequest requestWrapper = new SignHttpServletRequestWrapper((HttpServletRequest) request);
                  chain.doFilter(requestWrapper, response);
                  return;
              }
          }
          chain.doFilter(request, response);
      }
  
      @Override
      public void destroy() {}
  }

• 在配置类内新增一个 Bean 注册过滤器

  @Bean
  @Order
  public FilterRegistrationBean SignFilterRegistration() {
      FilterRegistrationBean registration = new FilterRegistrationBean();
      registration.setFilter(new SignFilter());
      registration.addUrlPatterns("/*");
      registration.setName("SignFilter");
      registration.setOrder(Integer.MAX_VALUE);
      return registration;
  }

• 新增一个用到了 getInputStream 的拦截器

  package com.sixi.enquiry.interceptor;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.springframework.stereotype.Component;
  import org.springframework.util.StreamUtils;
  import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
  
  /**
   * @author 喵♂呜
   * @since 2017/5/31
   */
  @Component
  public class SignInterceptor extends HandlerInterceptorAdapter {
      private String SignHeader = "Sixi-Signature";
  
      @Override
      public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
          StreamUtils.copyToString(request.getInputStream(), Charset.forName("UTF-8"));
          return true;
      }
  }

• 新增控制器 打印数据

  package com.sixi.enquiry.controller;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  
  import javax.servlet.http.HttpServletRequest;
  
  import org.springframework.util.StreamUtils;
  import org.springframework.web.bind.annotation.PostMapping;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  
  /**
   * Created with IntelliJ IDEA
   *
   * @author 喵♂呜
   * Created on 2017/12/21 19:04.
   */
  @RestController
  @RequestMapping("/test")
  public class TestController {
      @PostMapping
      public String test(HttpServletRequest request) throws IOException {
          return StreamUtils.copyToString(request.getInputStream(), Charset.forName("UTF-8"));
      }
  }

• 使用CURL测试 可以获得数据

  $ curl -sX POST http://172.30.34.3:1221/test \
  >   -H 'Content-Type: application/json' \
  >   -d '{"id":111,"userId":1,"amount":100,"products":[{"id":123,"name":"testproduct","price":23}]}'
  {"id":111,"userId":1,"amount":100,"products":[{"id":123,"name":"testproduct","price":23}]}