最近做的一个项目中，需要在拦截器中校验参数是否被篡改，所以需要在json字符串反序列化前，提前获取request中的字节数据，但这样会在后续反序列化时报错，原因是request.getInputStream()只能被调用一次，解决办法就是在过滤器中对request请求进行包装，创建一个body[]数组，将流中数据读出保存到body中，以便后续可以反复读取，在重写getInputStream()方法，下附解决步骤：
1.创建request请求包装类的对象
//request请求的包装类
public class RequestWrapper extends HttpServletRequestWrapper {String default_charset = "utf-8";private final byte[] body;public RequestWrapper(HttpServletRequest request) throws IOException {super(request);ServletInputStream inputStream = request.getInputStream();ByteArrayOutputStream out = new ByteArrayOutputStream();byte[] buf = new byte[1024];int len=0;while ((len = inputStream.read(buf))!=-1){out.write(buf,0,len);}out.flush();this.body = out.toByteArray();out.close();}public byte[] getBody() {return body;}public String getBodyString() {return new String(body, Charset.forName(default_charset));}public BufferedReader getReader() throws IOException {return new BufferedReader(new InputStreamReader(getInputStream()));}public ServletInputStream getInputStream() throws IOException {final ByteArrayInputStream inputStream = new ByteArrayInputStream(this.body);return new ServletInputStream() {public int read() throws IOException {return inputStream.read();}public boolean isFinished() {return false;}public boolean isReady() {return false;}public void setReadListener(ReadListener readListener) {}};}}2.在过滤器中进行用自己创建的包装类对象替换
public class ReplaceStreamFilter implements Filter {@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {RequestWrapper wrapper = new RequestWrapper((HttpServletRequest)request);log.info("request请求对象被替换。。。。。。。。。。。。。。。。。。");chain.doFilter(wrapper,response);}@Overridepublic void destroy() {}
}3.在后续校验中直接获取即可