HttpServletRequest重复读取

拼搏现实的明天。 2021-12-21 10:41 225阅读 0赞

# 背景概述 #

最近公司要求在之前的项目APP接口里面加入端口校验功能，实现起来很简单，就是通过添加拦截器的方式，在interceptor中读取端口参数，校验该端口在配置文件中是否有存在，存在返回已占用，请重新输入，不存在就添加该服务。

接口中主要是json格式，其对应的是payload请求，不可以通过request的getParameter()方法直接获取，需要通过getRead或者getInputStream方法获取流，通过流读取body，将body转化成JsonObject来获取。读取之后就出现了下面的错误。

{ 
      "timestamp": "2019-06-27T04:02:37.865+0000",
      "status": 400,
      "error": "Bad Request",
      "message": "Required request body is missing: public void com.infosec.netsafess.controller.UserController.save(com.infosec.netsafess.entity.User)",
      "trace": "org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing: public void com.infosec.netsafess.controller.UserController.save(com.infosec.netsafess.entity.User)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:160)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:130)\r\n\tat org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:126)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)\r\n\tat org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892)\r\n\tat org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)\r\n\tat org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039)\r\n\tat org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)\r\n\tat org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)\r\n\tat org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:660)\r\n\tat org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)\r\n\tat javax.servlet.http.HttpServlet.service(HttpServlet.java:741)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat com.infosec.netsafess.filter.SignValidateFilter.doFilter(SignValidateFilter.java:28)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)\r\n\tat org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)\r\n\tat org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)\r\n\tat org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:200)\r\n\tat org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)\r\n\tat org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:490)\r\n\tat org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)\r\n\tat org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)\r\n\tat org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)\r\n\tat org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)\r\n\tat org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)\r\n\tat org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)\r\n\tat org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:836)\r\n\tat org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1747)\r\n\tat org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)\r\n\tat java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)\r\n\tat java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)\r\n\tat org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)\r\n\tat java.lang.Thread.run(Thread.java:748)\r\n",
      "path": "/user/save"
    }

大概的意思是说request里面的流只能使用一次，在拦截器中使用完了就不能再次使用，网上的攻略很多，有的说需要自己重写HttpServletRequestWrapper，有的说通过spring自带的ContentCachingRequestWrapper就可以，我复制过来了，然而并没有什么用，还是报那个错。但是我看网上有几个都说这样可以，后来才发现他们是在 chain.doFilter(requestWrapper, response)之后再通过requestWrapper.getContentAsByteArray方法获取数据，或者在filter中读取了inputstream之后，在controller接口方法中使用requestWrapper.getContentAsByteArray方法再获取数据，这样就不能使用@RequestBody自动注入参数了，这显然不是我想要达到的效果。

我在他们的基础上做了一些修改，主要做的是读取了inputStream之后，再将数据写回去，具体实现如下：

# 第一步重写HttpServletRequestWrapper #

package com.infosec.netsafess.filter;
    
    import java.io.BufferedReader;
    import java.io.ByteArrayInputStream;
    import java.io.IOException;
    import java.io.InputStreamReader;
    
    import javax.servlet.ReadListener;
    import javax.servlet.ServletInputStream;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletRequestWrapper;
    
    import org.apache.commons.io.IOUtils;
    
    public class ContentCachingRequestWrapper extends HttpServletRequestWrapper{ 
    
        private byte[] body;
    
        private BufferedReader reader;
    
        private ServletInputStream inputStream;
    
        public ContentCachingRequestWrapper(HttpServletRequest request) throws IOException{ 
            super(request);
            loadBody(request);
        }
    
        private void loadBody(HttpServletRequest request) throws IOException{ 
            body = IOUtils.toByteArray(request.getInputStream());
            inputStream = new RequestCachingInputStream(body);
        }
    
        public byte[] getBody() { 
            return body;
        }
    
        @Override
        public ServletInputStream getInputStream() throws IOException { 
            if (inputStream != null) { 
                return inputStream;
            }
            return super.getInputStream();
        }
    
        @Override
        public BufferedReader getReader() throws IOException { 
            if (reader == null) { 
                reader = new BufferedReader(new InputStreamReader(inputStream, getCharacterEncoding()));
            }
            return reader;
        }
    
        private static class RequestCachingInputStream extends ServletInputStream { 
    
            private final ByteArrayInputStream inputStream;
    
            public RequestCachingInputStream(byte[] bytes) { 
                inputStream = new ByteArrayInputStream(bytes);
            }
            @Override
            public int read() throws IOException { 
                return inputStream.read();
            }
    
            @Override
            public boolean isFinished() { 
                return inputStream.available() == 0;
            }
    
            @Override
            public boolean isReady() { 
                return true;
            }
    
            @Override
            public void setReadListener(ReadListener readlistener) { 
            }
    
        }
    
    }

# 配置过滤器 #

package com.infosec.netsafess.filter;
    
    import lombok.extern.java.Log;
    import org.apache.commons.io.IOUtils;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    
    import javax.servlet.*;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    import java.io.IOException;
    
    @Component
    @Log
    @WebFilter(filterName = "test",urlPatterns = "/*")
    public class SignValidateFilter implements Filter{ 
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { 
            ContentCachingRequestWrapper requestWrapper = new ContentCachingRequestWrapper((HttpServletRequest) request);
            String body = IOUtils.toString(requestWrapper.getBody(),request.getCharacterEncoding());
            log.info(body);
            chain.doFilter(requestWrapper, response);
        }
    
        @Override
        public void destroy() { 
    
        }
    }

# 在拦截器中使用 #

package com.infosec.netsafess.interceptor;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONObject;
    import com.infosec.netsafess.annotation.LoginRequired;
    import com.infosec.netsafess.filter.ContentCachingRequestWrapper;
    import org.apache.commons.io.IOUtils;
    import org.springframework.web.method.HandlerMethod;
    import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.lang.reflect.Method;
    
    public class AuthorityInterceptor extends HandlerInterceptorAdapter { 
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { 
            if(!(handler instanceof HandlerMethod)){ 
                return true;
            }
    
            //START: 方法注解级拦截器
            HandlerMethod handlerMethod = (HandlerMethod) handler;
            Method method = handlerMethod.getMethod();
            //判断接口是否需要登录
            LoginRequired methodAnnotation = method.getAnnotation(LoginRequired.class);
            //有@LoginRequired注解，需要认证
            if(methodAnnotation != null){ 
                System.out.println("========================");
                ContentCachingRequestWrapper requestWapper = null;
                if(request instanceof HttpServletRequest){ 
                    requestWapper = (ContentCachingRequestWrapper) request;
                }
                String body = IOUtils.toString(requestWapper.getBody(),request.getCharacterEncoding());
                System.out.println(body);
                JSONObject obj = JSON.parseObject(body);
                System.out.println(obj);
            }
            return true;
        }
    }

补充一点：拦截器是在过滤器的doFilter方法中执行的，根据debugger