问题描述
项目中采用spring aop进行日志记录,在切面类通知方法中编写日志逻辑时,需要获取HttpSevletRequest
中的请求参数;对于普通参数来说,没有任何问题,但是当请求方式为POST/PUT
并并且是@RequestBody
标记的请求,在获取JSON参数时,会出现java.io.IOException: Stream closed
异常;
原因
HttpServletReqeust获取输入流时仅允许读取一次,spring已经对@ReqeustBody
提前进行了处理,通过断点调试发现,aop代码中获取request.getInputStream()
时,输入流已经关闭,因此出现流已经关闭的异常;
异常信息:
java.io.IOException: Stream closed
at org.apache.catalina.connector.InputBuffer.read(InputBuffer.java:372)
at org.apache.catalina.connector.CoyoteInputStream.read(CoyoteInputStream.java:190)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:161)
at java.io.BufferedReader.readLine(BufferedReader.java:324)
at java.io.BufferedReader.readLine(BufferedReader.java:389)
at com.dongzz.cms.common.utils.WebUtil.getParamsJson(WebUtil.java:151)
at com.dongzz.cms.common.annotation.aspect.LogHandlerAdvice.recordSysLogs(LogHandlerAdvice.java:83)
at com.dongzz.cms.common.annotation.aspect.LogHandlerAdvice.handleSysLogs(LogHandlerAdvice.java:44)
解决思路
重新构建ServletRequest
,读取输入流后进行缓存,然后重写进流里面,使请求输入流支持二次读取;
自定义
HttpServletRequestWrapper
,重新构建请求对象;packagecom.dongzz.cms.common.filter;importjavax.servlet.ServletInputStream;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletRequestWrapper;importjava.io.*;importjava.nio.charset.StandardCharsets;/** * 重新构建 ServletRequest,读取输入流后进行缓存,然后重写进流里面,使请求输入流支持二次读取 */publicclassRequestWrapperextendsHttpServletRequestWrapper{privatefinalbyte[] body;publicRequestWrapper(HttpServletRequest request)throwsIOException{super(request); body=read(request.getInputStream()).getBytes(StandardCharsets.UTF_8);}@OverridepublicBufferedReadergetReader()throwsIOException{returnnewBufferedReader(newInputStreamReader(getInputStream()));}@OverridepublicServletInputStreamgetInputStream()throwsIOException{ByteArrayInputStream bis=newByteArrayInputStream(body);returnnewServletInputStream(){@Overridepublicintread()throwsIOException{return bis.read();}};}/** * 读取输入流中的参数,转化为字符串 * * @param is * @return */privateStringread(InputStream is){StringBuilder sb=newStringBuilder();BufferedReader reader=newBufferedReader(newInputStreamReader(is,StandardCharsets.UTF_8));try{String line;while((line= reader.readLine())!=null){ sb.append(line);}}catch(Exception e){ e.printStackTrace();}finally{if(null!= reader){try{ reader.close();}catch(IOException e){ e.printStackTrace();}}}return sb.toString();}}
自定义过滤器,用自定义的 ServletRequest 处理
@RequestBody
特殊请求;packagecom.dongzz.cms.common.filter;importorg.slf4j.Logger;importorg.slf4j.LoggerFactory;importorg.springframework.http.HttpMethod;importorg.springframework.http.MediaType;importjavax.servlet.*;importjavax.servlet.annotation.WebFilter;importjavax.servlet.http.HttpServletRequest;importjava.io.IOException;/** * 解决读取 @RequestBody 相关参数时,HttpServletRequest的输入流只能读取一次的问题 * 问题表现: java.io.IOException: Stream closed */@WebFilter( filterName="bodyFilter", urlPatterns="/*")publicclassRequestBodyFilterimplementsFilter{publicstaticfinalLogger logger=LoggerFactory.getLogger(RequestBodyFilter.class);@Overridepublicvoidinit(FilterConfig config)throwsServletException{ logger.debug("init request boy filter.");}@OverridepublicvoiddoFilter(ServletRequest servletRequest,ServletResponse servletResponse,FilterChain chain)throwsIOException,ServletException{ServletRequest requestWrapper=null;if(servletRequestinstanceofHttpServletRequest){HttpServletRequest request=(HttpServletRequest) servletRequest;String mehtod= request.getMethod();String contentType= request.getContentType();// 特殊处理 POST/PUT请求,忽略上传请求if((HttpMethod.POST.name().equals(mehtod)||HttpMethod.PUT.name().equals(mehtod))&&(!MediaType.MULTIPART_FORM_DATA_VALUE.equals(contentType))){ requestWrapper=newRequestWrapper(request);// 重新构建请求,新的对象读取输入流后进行缓存,然后重写进流,因此支持二次读取}}if(null== requestWrapper){ chain.doFilter(servletRequest, servletResponse);}else{ chain.doFilter(requestWrapper, servletResponse);}}@Overridepublicvoiddestroy(){ logger.debug("destroy request body filter.");}}
此时在 aop 通知方法中通过 HttpServletRequest 获取 @RequestBody 参数时能够取得相关的参数值,不会出现流已关闭的异常;