場景需求

• 介面地址、介面請求全域性過濾列印日誌
• 介面報錯時，通過釘釘等開放API傳送警告資訊

遇到問題

請求資料經過介面處理後，資料流已經關閉，無法再在報錯處理中通過讀取流的方式獲取body資料，HttpServlet本身也沒有類似getBody()的方法，所以無法在提醒中正確傳遞出問題介面的具體引數

解決思路

在全域性過濾器中，對所有請求通過過載HttpServletRequestWrapper的getInputStream複寫HttpServletRequest請求，將body引數讀取出來後，存入請求的attribute屬性中，後面如果有需要再次獲取引數時，不再通過流讀取，而是直接通過setAttribute

程式碼實現

// RequestWrapper.java
import org.apache.commons.io.IOUtils;

import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.*;

/**
 * @Description: 對HttpServletRequest進行重寫，
 * 1、用來接收application/json引數資料型別，即@RequestBody註解標註的引數,解決多次讀取問題
 * 2、用來解決註解@RequestParam通過POST/PUT/DELETE/PATCH方法傳遞引數，解決多次讀取問題
 * 首先看一下springboot控制器三個註解：
 * 1、@PathVariable註解是REST風格url獲取引數的方式，只能用在GET請求型別，通過getParameter獲取引數
 * 2、@RequestParam註解支援GET和POST/PUT/DELETE/PATCH方式，Get方式通過getParameter獲取引數和post方式通過getInputStream或getReader獲取引數
 * 3、@RequestBody註解支援POST/PUT/DELETE/PATCH，可以通過getInputStream和getReader獲取引數
 */
public class RequestWrapper extends HttpServletRequestWrapper {
    /**
     * 引數位元組陣列
     */
    private byte[] requestBody;
    /**
     * Http請求物件
     */
    private HttpServletRequest request;

    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        this.request = request;
    }

    /**
     * @return
     * @throws IOException
     */
    @Override
    public ServletInputStream getInputStream() throws IOException {
        /**
         * 每次呼叫此方法時將資料流中的資料讀取出來，然後再回填到InputStream之中
         * 解決通過@RequestBody和@RequestParam（POST方式）讀取一次後控制器拿不到引數問題
         */
        if (null == this.requestBody) {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            IOUtils.copy(request.getInputStream(), baos);
            this.requestBody = baos.toByteArray();
            // 後面需要拿請求體的地方通過getAttribute("body")獲取
            this.request.setAttribute("body", baos);
        }

        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 listener) {

            }

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

    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }
}
 

// ChannelFilter.java
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;

import java.io.IOException;

/**
 * 全域性介面請求攔截
 */
@Component
@WebFilter(filterName = "channelFilter", urlPatterns = {"/*"})
public class ChannelFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

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

    @Override
    public void destroy() {
    }
}