HttpServetRequest读取body只能一次的问题

HTTP请求中的是字符串数据：

 //字符串读取

 void charReader(HttpServletRequest request) {
     BufferedReader br = request.getReader();
     String str, wholeStr = "";
     while((str = br.readLine()) != null){
        wholeStr += str;
     }
     System.out.println(wholeStr);
 }
 //二进制读取

 void binaryReader(HttpServletRequest request) {
      int len = request.getContentLength();
      ServletInputStream iii = request.getInputStream();
16      byte[] buffer = new byte[len];
      iii.read(buffer, 0, len);
 }

注意：

request.getInputStream();   request.getReader();  和request.getParameter("key");

这三个函数中任何一个函数执行一次后（可正常读取body数据），之后再执行就无效了。

解决方法： 包装HttpServletRequest对象，缓存body数据，再次读取的时候将缓存的值写出

 package com.nd.sdp.formatastic.common.interceptor;

 import javax.servlet.ServletInputStream;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletRequestWrapper;
 import java.io.*;

 /**
  * @author weihainan.
  * @since 0.1 created on 2017/2/23.
  */
 public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {

     private final String body;

     public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
         super(request);
         StringBuilder stringBuilder = new StringBuilder();
         BufferedReader bufferedReader = null;
         try {
             InputStream inputStream = request.getInputStream();
             if (inputStream != null) {
                 bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                 char[] charBuffer = new char[128];
                 int bytesRead = -1;
                 while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                     stringBuilder.append(charBuffer, 0, bytesRead);
                 }
             } else {
                 stringBuilder.append("");
             }
         } catch (IOException ex) {
             throw ex;
         } finally {
             if (bufferedReader != null) {
                 try {
                     bufferedReader.close();
                 } catch (IOException ex) {
                     throw ex;
                 }
             }
         }
         body = stringBuilder.toString();
     }

     @Override
     public ServletInputStream getInputStream() throws IOException {
         final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
         ServletInputStream servletInputStream = new ServletInputStream() {
             public int read() throws IOException {
                 return byteArrayInputStream.read();
             }
         };
         return servletInputStream;
     }

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

     public String getBody() {
         return this.body;
     }
 }

使用Filter替换HttpServletRequest对象

 package com.nd.sdp.formatastic.common.interceptor;

 import javax.servlet.*;
 import javax.servlet.annotation.WebFilter;
 import javax.servlet.http.HttpServletRequest;
 import java.io.IOException;

 /**
  * @author weihainan.
  * @since 0.1 created on 2017/2/23.
  */
 @WebFilter(filterName = "httpServletRequestWrapperFilter", urlPatterns = "/*")
 public class HttpServletRequestWrapperFilter implements Filter {

     @Override
     public void init(FilterConfig filterConfig) throws ServletException {

     }

     @Override
     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
             throws IOException, ServletException {

         ServletRequest requestWrapper = null;
         if (request instanceof HttpServletRequest) {
             requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
         }
         if (null == requestWrapper) {
             chain.doFilter(request, response);
         } else {
             chain.doFilter(requestWrapper, response);
         }

     }

     @Override
     public void destroy() {

     }
 }