缓存request流

当接口请求的时候使用application/json之类的文本格式的时候，获取的时候需要从request的body体里获取，当需要使用过滤器、拦截器或者AOP的时候，难免会遇到读流的问题，拦截到的request读取过一次之后在Controller中就无法再获取，此处记录解决方案：

ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
HttpServletRequest request = attributes.getRequest();
// 缓存request到ApiHttpServletRequestWrapper中
ApiHttpServletRequestWrapper wrapper = new ApiHttpServletRequestWrapper(request);
String jsonStr = RequestJsonUtil.getRequestJsonString(wrapper);
Map<String, Object> param = JSONObject.fromObject(jsonStr);

ApiHttpServletRequestWrapper.java

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.springframework.util.StreamUtils;

/**
 * 重写HttpServletRequestWrapper的方法
 */
public class ApiHttpServletRequestWrapper extends HttpServletRequestWrapper {

    private byte[] requestBody = null;

    public ApiHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);
        //缓存请求body
        try {
            requestBody = StreamUtils.copyToByteArray(request.getInputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 重写 getInputStream()
     */
    @Override
    public ServletInputStream getInputStream() throws IOException {
        if(requestBody == null){
            requestBody= new byte[0];
        }
        final ByteArrayInputStream bais = new ByteArrayInputStream(requestBody);
        return new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return false;
            }

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

            @Override
            public void setReadListener(ReadListener readListener) {

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

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

RequestJsonUtil.java

import java.io.IOException;
import javax.servlet.http.HttpServletRequest;
import org.springframework.web.bind.annotation.RequestMethod;

/**
 * 请求Json工具类
 */
public class RequestJsonUtil {

    /***
     * 获取 request 中 json 字符串的内容
     * @param request
     * @return
     * @throws IOException
     */
    public static String getRequestJsonString(HttpServletRequest request)
            throws IOException {
        String submitMehtod = request.getMethod();
        // GET
        if (submitMehtod.equals(RequestMethod.GET)) {
            return new String(request.getQueryString().getBytes("iso-8859-1"), "utf-8").replaceAll("%22", "\"");
            // POST
        } else {
            return getRequestPostStr(request);
        }
    }

    /**
     * 获取 post 请求的 byte[] 数组
     * @param request
     * @return
     * @throws IOException
     */
    public static byte[] getRequestPostBytes(HttpServletRequest request)
            throws IOException {
        int contentLength = request.getContentLength();
        if (contentLength < 0) {
            return null;
        }
        byte buffer[] = new byte[contentLength];
        for (int i = 0; i < contentLength; ) {

            int readlen = request.getInputStream().read(buffer, i,
                    contentLength - i);
            if (readlen == -1) {
                break;
            }
            i += readlen;
        }
        return buffer;
    }

    /**
     * 获取 post 请求内容
     * @param request
     * @return
     * @throws IOException
     */
    public static String getRequestPostStr(HttpServletRequest request)
            throws IOException {
        byte buffer[] = getRequestPostBytes(request);
        String charEncoding = request.getCharacterEncoding();
        if (charEncoding == null) {
            charEncoding = "UTF-8";
        }
        return new String(buffer, charEncoding);
    }
}

最后，需要把所有请求都过滤一遍

package com.sq580.openapi.config;

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.sq580.openapi.filter.HttpServletRequestReplacedFilter;

/**
 * 自定义Filter配置
 */
@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean httpServletRequestReplacedFilter() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(new HttpServletRequestReplacedFilter());
        registration.addUrlPatterns("/*");
        registration.addInitParameter("paramName", "paramValue");
        registration.setName("httpServletRequestReplacedFilter");
        registration.setOrder(1);
        return registration;
    }

}

import com.sq580.ms.institution.facade.util.request.ApiHttpServletRequestWrapper;
import lombok.extern.slf4j.Slf4j;

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

/**
 * ClassName: HttpServletRequestReplacedFilter<br/>
 * Function: TODO ADD FUNCTION(可选)<br/>
 * Reason: TODO ADD REASON(可选)<br/>
 * Date: 2017-11-06 19:09<br/>
 *
 * @author zoro
 */
@Slf4j
public class HttpServletRequestReplacedFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        log.info("httpServletRequestReplacedFilter init, FilterConfig:{}",filterConfig);
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain) throws IOException, ServletException {
        ServletRequest requestWrapper = null;
        if(request instanceof HttpServletRequest) {
            requestWrapper = new ApiHttpServletRequestWrapper((HttpServletRequest) request);
        }
        if(requestWrapper == null) {
            chain.doFilter(request, response);
        } else {
            chain.doFilter(requestWrapper, response);
        }
    }

    @Override
    public void destroy() {
        log.info("httpServletRequestReplacedFilter destroy.");
    }

}