攔截器中，request中getReader()和getInputStream()只能調用一次，構建可重複讀取inputStream的request.

由於 request中getReader()和getInputStream()只能調用一次

在項目中，可能會出現需要針對接口參數進行校驗等問題。

因此，針對這問題，給出一下解決方案

 

實現方法：先將RequestBody保存爲一個byte數組，然後通過Servlet自帶的HttpServletRequestWrapper類覆蓋getReader()和getInputStream()方法，使流從保存的byte數組讀取。然後再Filter中將ServletRequest替換爲ServletRequestWrapper。代碼如下： 

BodyReaderHttpServletRequestWrapper類包裝ServletRequest，將流保存爲byte[]，然後將getReader()和getInputStream()方法的流的讀取指向byte[] 

http://zhangbo-peipei-163-com.iteye.com/blog/2022460

step 1:

添加RepeatedlyReadRequestWrapper 類並繼承 HttpServletRequestWrapper 包裝類

package com.config;

import org.apache.commons.lang3.StringUtils;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;

public class RepeatedlyReadRequestWrapper extends HttpServletRequestWrapper {
    private final byte[] body;

    public RepeatedlyReadRequestWrapper(HttpServletRequest request)
            throws IOException {
        super(request);
        body = readBytes(request.getReader(), "utf-8");
    }

    @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 boolean isFinished() {
            return false;
            }

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

            @Override
            public void setReadListener(ReadListener listener) {

            }

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

    /**
     * 通過BufferedReader和字符編碼集轉換成byte數組
     * @param br
     * @param encoding
     * @return
     * @throws IOException
     */
    private byte[] readBytes(BufferedReader br,String encoding) throws IOException{
        String str = null,retStr="";
        while ((str = br.readLine()) != null) {
            retStr += str;
        }
        if (StringUtils.isNotBlank(retStr)) {
            return retStr.getBytes(Charset.forName(encoding));
        }
        return null;
    }
}

 

step 2:

添加 RepeatedlyReadFilter 實現 filter 過濾器接口方法，當客戶端的請求先 過濾 進入SpringMvc Dispatch 路由前先包裝下

package com.filter;

import com.config.RepeatedlyReadRequestWrapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

/**
 * 複製請求數據包body
 * 以提供 攔截器下 可數次獲取Body數據包*/
public class RepeatedlyReadFilter implements Filter {

    private static final Logger logger = LoggerFactory.getLogger(RepeatedlyReadFilter.class);

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

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        logger.debug("複製request.getInputStream流");
        ServletRequest requestWrapper = null;
        if (request instanceof HttpServletRequest) {
            requestWrapper = new RepeatedlyReadRequestWrapper((HttpServletRequest) request);
        }
        if (null == requestWrapper) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }
    }

    @Override
    public void destroy() {

    }
}

step 3:

添加攔截器 RepeatedlyReadInterceptor 繼承 HandlerInterceptorAdapter 攔截適配器

package com.interceptor;

import com.config.RepeatedlyReadRequestWrapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

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

public class RepeatedlyReadInterceptor extends HandlerInterceptorAdapter {

    private static final Logger logger = LoggerFactory.getLogger(RepeatedlyReadInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        /**
         * 對來自後臺的請求統一進行日誌處理
         */
        RepeatedlyReadRequestWrapper requestWrapper;
        if (request instanceof RepeatedlyReadRequestWrapper) {
            // 簽名處理過程 start.... 
            requestWrapper = (RepeatedlyReadRequestWrapper) request;
            logger.info("請求Body: {} ", getBodyString(requestWrapper));
            // 簽名處理過程 end....
        }
        // 默認記錄後臺接口請求日誌記錄
        String url = request.getRequestURL().toString();
        String method = request.getMethod();
        String uri = request.getRequestURI();
        String queryString = request.getQueryString();
        logger.info(String.format("請求參數, url: %s, method: %s, uri: %s, params: %s ", url, method, uri, queryString));
        return super.preHandle(request, response, handler);
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        RepeatedlyReadRequestWrapper requestWrapper;
        if (request instanceof RepeatedlyReadRequestWrapper) {
            // 測試再次獲取Body start.... 
            requestWrapper = (RepeatedlyReadRequestWrapper) request;
            logger.info("請求Body: {} ", getBodyString(requestWrapper));
            // 測試再次獲取Body end....
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }

    /**
     * 獲取請求Body
     *
     * @param request
     *
     * @return
     */
    public static 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: 複製輸入流</br>
     *
     * @param inputStream
     *
     * @return</br>
     */
    public static 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;
    }
}

step 4:

配置過濾器與攔截器 WebMvcConfig

package com.config;

import com.filter.RepeatedlyReadFilter;
import com.interceptor.MyInterceptor;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.*;

/**
 * SpringMVC 配置類*/
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new RepeatedlyReadInterceptor()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }

    @Bean
    public FilterRegistrationBean repeatedlyReadFilter() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        RepeatedlyReadFilter repeatedlyReadFilter = new RepeatedlyReadFilter();
        registration.setFilter(repeatedlyReadFilter);
        registration.addUrlPatterns("/*");
        return registration;
    }
}

對於上述過濾器和攔截器的測試，可以得到如下結論：
（1）、Filter需要在web.xml中配置，依賴於Servlet；
（2）、Interceptor需要在SpringMVC中配置，依賴於框架；
（3）、Filter的執行順序在Interceptor之前，具體的流程見下圖；
這裏寫圖片描述
（4）、兩者的本質區別：攔截器（Interceptor）是基於Java的反射機制，而過濾器（Filter）是基於函數回調。從靈活性上說攔截器功能更強大些，Filter能做的事情，都能做，而且可以在請求前，請求後執行，比較靈活。Filter主要是針對URL地址做一個編碼的事情、過濾掉沒用的參數、安全校驗（比較泛的，比如登錄不登錄之類），太細的話，還是建議用interceptor。不過還是根據不同情況選擇合適的。
 

轉自：https://www.cnblogs.com/alter888/p/8919865.html

https://blog.csdn.net/zxd1435513775/article/details/80556034