POST参数为空，但存在于正文中

Question

我有一个应用程序，在本地工作很好，但在客户端，它崩溃，因为一个POST参数是NULL。

((HttpServletRequest)request).getParameter("dtid");

此返回为NULL。

因此，我添加了一个过滤器来记录请求的get/post/body。在本地，日志如下所示：

[方法:post][请求URI://peps/zkau][请求参数：{dtid=z_0n8,uuid_0=x38pz,data_0={“pagex”：372,“pagey”：103,“which”：1,“x”：40.79998779296875,“y”：4},cmd_0=onclick}][请求正文:][远程地址:0:0:0:0:0:0:0:0:0:0:1]

我在请求param中有dtid，主体是空的。在客户端上，相同的日志如下所示：

[方法:post][请求URI://peps/zkau][请求参数：{}][requestbody:dtid=z_cb50&cmd_0=onopen&uuid_0=l2st30&data_0=%7b%22open d&cmd_2=onopen&uuid_2=l2st30&data_2=%7b%22open%22%3afalse%7d][远程地址:x.x.x.x]

参数是一个空映射，但主体是满的。尸体似乎没有经过处理，是什么原因造成的？为什么不解析主体并将其注入参数映射中？

谢谢

下面是我的过滤器：

public class PepsParamFilter implements Filter {

    private static final Logger LOG = Logger.getLogger(PepsParamFilter.class.getName());

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

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        try {
            HttpServletRequest httpServletRequest = (HttpServletRequest) request;

            Map<String, String> requestMap = this.getTypesafeRequestMap(httpServletRequest);
            BufferedRequestWrapper bufferedReqest = new BufferedRequestWrapper(httpServletRequest);            

            chain.doFilter(bufferedReqest, response);

             //Request
                final StringBuilder reqMessage = new StringBuilder("").append("[METHOD:")
                        .append(httpServletRequest.getMethod())                        
                        .append("] [REQUEST URI:")
                        .append(httpServletRequest.getRequestURI())                        
                        .append("] [REQUEST PARAMETERS:").append(requestMap)
                        .append("] [REQUEST BODY:")
                        .append(bufferedReqest.getRequestBody())
                        .append("] [REMOTE ADDRESS:")
                        .append(httpServletRequest.getRemoteAddr()).append("]");
                if(!httpServletRequest.getRequestURI().endsWith(".gif")
                    && !httpServletRequest.getRequestURI().endsWith(".png")
                    && !httpServletRequest.getRequestURI().endsWith(".css")
                    ) {
                    LOG.info(reqMessage);
                }



        } catch (Throwable a) {
            LOG.error(a.getMessage(),a);
        }
    }

    private Map<String, String> getTypesafeRequestMap(HttpServletRequest request) {
        Map<String, String> typesafeRequestMap = new HashMap<String, String>();
        Enumeration<?> requestParamNames = request.getParameterNames();
        while (requestParamNames.hasMoreElements()) {
            String requestParamName = (String) requestParamNames.nextElement();
            String requestParamValue = request.getParameter(requestParamName);
            typesafeRequestMap.put(requestParamName, requestParamValue);
        }
        return typesafeRequestMap;
    }

    @Override
    public void destroy() {
    }

    private static final class BufferedRequestWrapper extends
            HttpServletRequestWrapper {

        private ByteArrayInputStream bais = null;
        private ByteArrayOutputStream baos = null;
        private BufferedServletInputStream bsis = null;
        private byte[] buffer = null;

        public BufferedRequestWrapper(HttpServletRequest req)
                throws IOException {
            super(req);
            // Read InputStream and store its content in a buffer.
            InputStream is = req.getInputStream();
            this.baos = new ByteArrayOutputStream();
            byte buf[] = new byte[1024];
            int letti;
            while ((letti = is.read(buf)) > 0) {
                this.baos.write(buf, 0, letti);
            }
            this.buffer = this.baos.toByteArray();
        }

        @Override
        public ServletInputStream getInputStream() {
            this.bais = new ByteArrayInputStream(this.buffer);
            this.bsis = new BufferedServletInputStream(this.bais);

            return this.bsis;
        }

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

        String getRequestBody() throws IOException {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    this.getInputStream()));
            String line = null;
            StringBuilder inputBuffer = new StringBuilder();
            do {
                line = reader.readLine();
                if (null != line) {
                    inputBuffer.append(line.trim());
                }
            } while (line != null);
            reader.close();
            return inputBuffer.toString().trim();
        }

    }

    private static final class BufferedServletInputStream extends
            ServletInputStream {

        private ByteArrayInputStream bais;

        public BufferedServletInputStream(ByteArrayInputStream bais) {
            this.bais = bais;
        }

        @Override
        public int available() {
            return this.bais.available();
        }

        @Override
        public int read() {
            return this.bais.read();
        }

        @Override
        public int read(byte[] buf, int off, int len) {
            return this.bais.read(buf, off, len);
        }

    }

    public class TeeServletOutputStream extends ServletOutputStream {

        private final TeeOutputStream targetStream;

        public TeeServletOutputStream(OutputStream one, OutputStream two) {
            targetStream = new TeeOutputStream(one, two);
        }

        @Override
        public void write(int arg0) throws IOException {
            this.targetStream.write(arg0);
        }

        public void flush() throws IOException {
            super.flush();
            this.targetStream.flush();
        }

        public void close() throws IOException {
            super.close();
            this.targetStream.close();
        }
    }


}

Answer 1

Servlet-spec的3.1.1节指出：

3.1.1参数可用时

将post表单数据填充到参数集之前，必须满足以下条件：

null

本质上，这两种状态都是有效的，这取决于您之前的请求发生了什么。

首先要检查的是浏览器是否发送了相同的请求（/body）和头。例如。在浏览器的开发人员工具中。如果它们是相同的，请检查web.xml中的其他筛选器（例如，本地开发环境和生产环境中的安全筛选器通常是不同的）。