Springboot项目拦截器中获取到请求参数后，controller获取不到

 

0 背景

         拦截器被用来获取用户的请求日志，好处多多。一般来说，请求参数通过GET和POST的方式传递，GET请求参数通过request.getParameterMap()方法获取，POST请求参数通过request.getInputStream()方法获取。

         但是，当在项目中使用拦截器获取到请求参数后，发现controller中@RequestBody注解获取不到参数了。多番查阅发现，Spring中的request.getInputStream()和request.getReader()只能被获取到一次，而@RequestBody的底层也是通过流来请求数据。于是，有必要将拦截器中的流数据保存下来，以便controller获取到数据。

 

1 自定义 RequestWrapper子类

     继承 HttpServletRequestWrapper类，封装HttpServletRequest请求

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;
import java.nio.charset.Charset;

/**
 * @author wangyan
 * @description  获取请求参数并处理
 * @date 2019/7/18 18:38
 */
public class RequestWrapper extends HttpServletRequestWrapper {
    private final byte[] body;
    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        String sessionStream = getBodyString(request);
        body = sessionStream.getBytes(Charset.forName("UTF-8"));
    }
    public String  getBodyString(){
        return new String(body,Charset.forName("UTF-8"));
    }
    /**
     * 获取请求Body
     *
     * @param request
     * @return
     */
    public String getBodyString(final ServletRequest request) {
        StringBuilder sb = new StringBuilder();
        InputStream inputStream = null;
        BufferedReader reader = null;
        try {
            inputStream = cloneInputStream(request.getInputStream());
            reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
            String line = "";
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                }
                catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }
    /**
     * Description: 复制输入流

     *
     * @param inputStream
     * @return

     */
    public InputStream cloneInputStream(ServletInputStream inputStream) {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len;
        try {
            while ((len = inputStream.read(buffer)) > -1) {
                byteArrayOutputStream.write(buffer, 0, len);
            }
            byteArrayOutputStream.flush();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        InputStream byteArrayInputStream = new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
        return byteArrayInputStream;
    }
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }
    @Override
    public ServletInputStream getInputStream() throws IOException {

        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
        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) {

            }
        };
    }
}

2 自定义过滤器

     将自定义请求 RequestWrapper 子类传递下去

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;
/**
 * @author wangyan
 * @description 自定义过滤器
 * @date 2019/7/19 18:26
 */
@Component
@WebFilter(urlPatterns = "/*",filterName = "channelFilter")
public class ChannelFilter implements Filter {
    private Logger logger = LoggerFactory.getLogger(ChannelFilter.class);

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

    }
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        logger.info("================进入过滤器======================");
        // 防止流读取一次后就没有了, 所以需要将流继续写出去
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        ServletRequest requestWrapper = new RequestWrapper(httpServletRequest);

        filterChain.doFilter(requestWrapper, servletResponse);
    }
    @Override
    public void destroy() {

    }
}

3 日志拦截器中的调用

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @author wangyan
 * @description  自定义拦截器
 * @date 2019/7/12 10:13
 */

@Component
public class BaseInterceptor extends HandlerInterceptorAdapter {
    protected final Logger logger = LoggerFactory.getLogger(this.getClass());

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        info("***************************【RequestBeginning】***************************");
        info("----------------StartProcessingRequest----------------");

        try {
            Long currentTime = System.currentTimeMillis();
            SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
            Date date = new Date(currentTime);
            info("CurrentTime：{}",formatter.format(date));
            info("ResponseTime:{}",(System.currentTimeMillis() - currentTime) + "ms");
            String requestURL = request.getRequestURI();
            info("RequestURL： {} ", requestURL);
            info("GetMethod: {}", handler);

            //获取请求参数
            RequestWrapper requestWrapper = new RequestWrapper(request);
            info("RequestBody: {}",requestWrapper.getBodyString());//这里getBodyString()方法无参数
        } catch (Exception e) {
            error("MVC业务处理-拦截器异常：", e);
        }
        info("-------------------------End-------------------------");
        return true;
    }

    /**
     * This implementation is empty.
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
                           @Nullable ModelAndView modelAndView) throws Exception {
        logger.info("after");

    }

    /**
     * This implementation is empty.
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
                                @Nullable Exception ex) throws Exception {
        logger.info("Completion");
    }

    /**
     * This implementation is empty.
     */
    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response,
                                               Object handler) throws Exception {
        logger.info("Concurrent");

    }

    protected final void error(String msg, Object... objects) {
        logger.error(msg, objects);
    }
    protected final void info(String msg, Object... objects) {
        logger.info(msg, objects);
    }
}

 

         至此结束！！！