HttpServetRequest读取body只能一次的问题

HTTP请求中的是字符串数据：

 1 //字符串读取 2   3 void charReader(HttpServletRequest request) { 4     BufferedReader br = request.getReader(); 5     String str, wholeStr = ""; 6     while((str = br.readLine()) != null){ 7        wholeStr += str; 8     } 9     System.out.println(wholeStr);10 }11 //二进制读取12  13 void binaryReader(HttpServletRequest request) {14      int len = request.getContentLength();15      ServletInputStream iii = request.getInputStream();16      byte[] buffer = new byte[len];17      iii.read(buffer, 0, len);18 }

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

 1 package com.nd.sdp.formatastic.common.interceptor; 2  3 import javax.servlet.ServletInputStream; 4 import javax.servlet.http.HttpServletRequest; 5 import javax.servlet.http.HttpServletRequestWrapper; 6 import java.io.*; 7  8 /** 9  * @author weihainan.10  * @since 0.1 created on 2017/2/23.11  */12 public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {13 14     private final String body;15 16     public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {17         super(request);18         StringBuilder stringBuilder = new StringBuilder();19         BufferedReader bufferedReader = null;20         try {21             InputStream inputStream = request.getInputStream();22             if (inputStream != null) {23                 bufferedReader = new BufferedReader(new InputStreamReader(inputStream));24                 char[] charBuffer = new char[128];25                 int bytesRead = -1;26                 while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {27                     stringBuilder.append(charBuffer, 0, bytesRead);28                 }29             } else {30                 stringBuilder.append("");31             }32         } catch (IOException ex) {33             throw ex;34         } finally {35             if (bufferedReader != null) {36                 try {37                     bufferedReader.close();38                 } catch (IOException ex) {39                     throw ex;40                 }41             }42         }43         body = stringBuilder.toString();44     }45 46     @Override47     public ServletInputStream getInputStream() throws IOException {48         final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());49         ServletInputStream servletInputStream = new ServletInputStream() {50             public int read() throws IOException {51                 return byteArrayInputStream.read();52             }53         };54         return servletInputStream;55     }56 57     @Override58     public BufferedReader getReader() throws IOException {59         return new BufferedReader(new InputStreamReader(this.getInputStream()));60     }61 62     public String getBody() {63         return this.body;64     }65 }

 

使用Filter替换HttpServletRequest对象

 1 package com.nd.sdp.formatastic.common.interceptor; 2  3 import javax.servlet.*; 4 import javax.servlet.annotation.WebFilter; 5 import javax.servlet.http.HttpServletRequest; 6 import java.io.IOException; 7  8 /** 9  * @author weihainan.10  * @since 0.1 created on 2017/2/23.11  */12 @WebFilter(filterName = "httpServletRequestWrapperFilter", urlPatterns = "/*")13 public class HttpServletRequestWrapperFilter implements Filter {14 15     @Override16     public void init(FilterConfig filterConfig) throws ServletException {17 18     }19 20     @Override21     public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)22             throws IOException, ServletException {23 24         ServletRequest requestWrapper = null;25         if (request instanceof HttpServletRequest) {26             requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);27         }28         if (null == requestWrapper) {29             chain.doFilter(request, response);30         } else {31             chain.doFilter(requestWrapper, response);32         }33 34     }35 36     @Override37     public void destroy() {38 39     }40 }