攔截器獲取request的值之後，Controller拿不到值

原因：

在Spring中request的只能被獲取一次，攔截器獲取之後就會導致Controller拿不到值

解決方法：

將request的值進行備份，請求到達Controller的時候就會拿到這個值

1. 創建一個自己的HttpServletRequestWrapper並繼承servlet的HttpServletRequestWrapper，爲了備份request中的 值。

   public class MyHttpServletRequestWrapper extends HttpServletRequestWrapper {
   
       private final byte[] buff;
   
       public MyHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
           super(request);
           InputStream is = request.getInputStream();
           ByteArrayOutputStream baos = new ByteArrayOutputStream();
           byte[] b = new byte[1024];
           int len;
           while ((len = is.read(b)) != -1) {
               baos.write(b, 0, len);
           }
           buff = baos.toByteArray();
       }
   
       @Override
       public ServletInputStream getInputStream() throws IOException {
           final ByteArrayInputStream bais = new ByteArrayInputStream(buff);
           return new ServletInputStream() {
               @Override
               public int read() throws IOException {
                   return bais.read();
               }
           };
       }
   
       @Override
       public BufferedReader getReader() throws IOException {
           return new BufferedReader(new InputStreamReader(getInputStream()));
       }
   }

    

2. 創建一個Filter，將該攔截器配置在項目中，爲了調用備份的HttpServletRequestWrapper

   public class MyRequestBodyFilter implements Filter {
   
       @Override
       public void init(FilterConfig filterConfig) throws ServletException {
   
       }
   
       @Override
       public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
           HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
           servletRequest = new MyHttpServletRequestWrapper(httpServletRequest);
           filterChain.doFilter(servletRequest, servletResponse);
       }
   
       @Override
       public void destroy() {
   
       }
   }

    

3. 創建一個工具類，在攔截器中獲取request的值

   public class RequestUtils {
   
       public static String getRequestValue(HttpServletRequest request) throws IOException {
           StringBuffer sb = new StringBuffer();
           MyHttpServletRequestWrapper myHttpServletRequestWrapper = new MyHttpServletRequestWrapper(request);
           InputStream is = myHttpServletRequestWrapper.getInputStream();
           BufferedReader br = new BufferedReader(new InputStreamReader(is));
           String str;
           while ((str = br.readLine()) != null) {
               sb.append(str);
           }
           return sb.toString();
       }
   
   }