#12解决request中getReader()和getInputStream()只能调用一次的问题

目录

1、背景

2、解决方案

2.1、自定义HttpServletRequestWrapper

2.2、JsonRequestHeaderParamsHelper

2.3、HttpServletRequestReplacedFilter

2.4、使用

---

1、背景

当前系统Content-Type为application/json，参数接收方式采用@RequestBody和@RequestParam，但Interceptor拦截器和Aspect切面中存在再次调用request获取其中请求参数或者请求头等操作，导致报错getReader()和getInputStream()只能调用一次（getInputStream() has already been called for this request）。

2、解决方案

2.1、自定义HttpServletRequestWrapper

由于请求信息存储在流中，只能调用一次，因此将其存储到字节数组中，保证之后调用getReader()和getInputStream()均通过body数组来获取数据。

public class BodyReaderHttpServletRequestWrapper extends
HttpServletRequestWrapper {private final byte[] body;public BodyReaderHttpServletRequestWrapper(HttpServletRequest request)throws IOException {super(request);body = JsonRequestHeaderParamsHelper.bufferReaderToString(request.getReader()).getBytes();}@Overridepublic BufferedReader getReader() throws IOException {return new BufferedReader(new InputStreamReader(getInputStream()));}@Overridepublic ServletInputStream getInputStream() throws IOException {final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body);return new ServletInputStream() {@Overridepublic boolean isFinished() {return false;}@Overridepublic boolean isReady() {return false;}@Overridepublic void setReadListener(ReadListener readListener) {}@Overridepublic int read() {return byteArrayInputStream.read();}};}
}

2.2、JsonRequestHeaderParamsHelper

@Slf4j
public class JsonRequestHeaderParamsHelper {public static JSONObject parseHeader(ServletRequest request) throws IOException {return JSON.parseObject(bufferReaderToString(request.getReader()));}public static String bufferReaderToString(BufferedReader reader) throws IOException {StringBuilder sb = new StringBuilder();try  {char[] buff = new char[1024];int len;while ((len = reader.read(buff)) != -1) {sb.append(buff, 0, len);}} catch (IOException e) {log.error("bufferReaderToString error", e);}return sb.toString();}
}

2.3、HttpServletRequestReplacedFilter

通过Order(0)使其最优先加载，保证所有请求都先将request替换为自定义的。

此处的init()和destroy()方法不要使用super.init()，务必清空idea自动生成的内容。

@Slf4j
@Order(value = 0)
@WebFilter(filterName = "httpServletRequestReplacedFilter", urlPatterns = "/*")
public class HttpServletRequestReplacedFilter implements Filter {@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {log.info("进入HttpServletRequestReplacedFilter");ServletRequest requestWrapper = null;if(request instanceof HttpServletRequest) {requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);}if(null == requestWrapper) {chain.doFilter(request, response);} else {chain.doFilter(requestWrapper, response);}}@Overridepublic void init(FilterConfig filterConfig) throws ServletException {}@Overridepublic void destroy() {}
}

2.4、使用

之后就可以愉快地使用request.getParameter，@RequestBody等等了。

附上get和post手动获取请求参数的方法：

        if("GET".equals(request.getMethod())|| "DELETE".equals(request.getMethod())) {JSONObject jsonObject = JSONObject.fromObject(request.getParameterMap());params=jsonObject.toString();log.info("get请求参数为：{}", params);}else {com.alibaba.fastjson.JSONObject jsonObject =JsonRequestHeaderParamsHelper.parseHeader(request);params=jsonObject.toJSONString();log.info("post请求参数为：{}",params);}

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