解决request请求流只能读取一次的问题

实际开发碰到的问题

springboot项目中，为了防止sql注入，采用Filter拦截器对所有请求流中的json数据进行校验，请求数据没问题则继续向下执行，在后边的代码中应用到请求参数值时，发现request中的json数据为空；
除上边描述的情况，尝试过两次从request中获取json数据，第二次同样是获取不到的。

解决request请求流中的数据二次或多次使用问题

继承HttpServletRequestWrapper，将请求体中的流copy一份，覆写getInputStream()和getReader()方法供外部使用。每次调用覆写后的getInputStream()方法都是从复制出来的二进制数组中进行获取，这个二进制数组在对象存在期间一直存在，这样就实现了流的重复读取。

public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
    //保存流
    private byte[] requestBody = null;

    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        requestBody = StreamUtils.copyToByteArray(request.getInputStream());
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream bais = new ByteArrayInputStream(requestBody);

        return new ServletInputStream() {

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

            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }
        };
    }

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

@Component
@WebFilter
public class RequestSqlValidFilter implements Filter {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

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

    }

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

        //请求参数合法，无sql注入
        if((sqlValid(request, response))){
            chain.doFilter(requestWrapper, response);//requestWrapper中保存着供二次使用的请求数据
        }else {
            logger.error("RequestSqlValidFilter sqlValid param error");
        }
    }

    @Override
    public void destroy() {

    }