springboot利用filter獲取request和response中的數據

package liu.hope.my_demo_boot.filter;

import com.alibaba.fastjson.JSONObject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.*;
import java.nio.charset.StandardCharsets;

@Order(1)
@Component
@WebFilter(filterName = "webLogFilter", urlPatterns = "/*")
public class WebLogFilter implements Filter {
    private final static Logger logger = LoggerFactory.getLogger(WebLogFilter.class);
    private ThreadLocal<Long> threadLocal = new ThreadLocal<>();

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

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        // 包裝request和response
        RequestWrapper requestWrapper = new RequestWrapper((HttpServletRequest) request);
        ResponseWrapper responseWrapper = new ResponseWrapper((HttpServletResponse) response);
        // 獲取request的相關數據
        logger.debug("請求URL : " + requestWrapper.getRequestURL().toString());
        logger.debug("請求參數 : " + requestWrapper.getBody());
        threadLocal.set(System.currentTimeMillis());
        chain.doFilter(requestWrapper, responseWrapper);
        // 獲取response的相關數據
        logger.debug("響應數據 : " + new String(responseWrapper.getContent(), "UTF-8"));
        logger.debug("請求處理時間 : " + (System.currentTimeMillis() - threadLocal.get()) + "ms");
        // 在得到響應的數據之後，response的輸出流中就無可用的數據，所以需要巴數據放回去
        ServletOutputStream outputStream = response.getOutputStream();
        outputStream.write(responseWrapper.getContent());
        outputStream.flush();
        outputStream.close();
    }

    @Override
    public void destroy() {
    }
}

class RequestWrapper extends HttpServletRequestWrapper {
    private String body;

    /**
     * Constructs a request object wrapping the given request.
     * @param request The request to wrap
     * @throws IllegalArgumentException if the request is null
     */
    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        // 此處是得到請求內容的長度
        int contentLength = request.getContentLength();
        StringBuilder stringBuilder = new StringBuilder(contentLength);
        BufferedReader bufferedReader = null;
        InputStream inputStream = null;
        try {
            // 輸入流獲取請求的數據
            inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[1024];
                int bytesRead;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            }
        } catch (IOException e) {
            throw e;
        } finally {
            if (inputStream != null) {
                inputStream.close();
            }
            if (bufferedReader != null) {
                bufferedReader.close();
            }
        }
        // 下面會把數據放回request的輸入流中，所以要把數據恢復到與之前請求內容相同的長度
        body = String.format("%-" + contentLength + "s", JSONObject.parseObject(stringBuilder.toString()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        // 數據放到字節流中
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(this.getBody().getBytes());
        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 {
                // 數據放回request的輸入流中
                return byteArrayInputStream.read();
            }
        };
    }

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

    public String getBody() {
        // 請求中的數據
        return this.body;
    }
}

class ResponseWrapper extends HttpServletResponseWrapper {
    private ByteArrayOutputStream byteArrayOutputStream;
    private ServletOutputStream servletOutputStream;

    /**
     * Constructs a response adaptor wrapping the given response.
     * @param response The response to be wrapped
     * @throws IllegalArgumentException if the response is null
     */
    public ResponseWrapper(HttpServletResponse response) throws IOException {
        super(response);
        byteArrayOutputStream = new ByteArrayOutputStream();
        servletOutputStream = new MyServletOutputStream(byteArrayOutputStream);
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        return servletOutputStream;
    }

    @Override
    public PrintWriter getWriter() throws IOException {
        return new PrintWriter(new OutputStreamWriter(byteArrayOutputStream, StandardCharsets.UTF_8));
    }

    @Override
    public void flushBuffer() {
        if (servletOutputStream != null) {
            try {
                servletOutputStream.flush();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public byte[] getContent() {
        flushBuffer();
        // response中的數據
        return byteArrayOutputStream.toByteArray();
    }

    class MyServletOutputStream extends ServletOutputStream {
        // 把response輸出流中的數據寫入字節流中
        private ByteArrayOutputStream byteArrayOutputStream;

        public MyServletOutputStream(ByteArrayOutputStream byteArrayOutputStream) {
            this.byteArrayOutputStream = byteArrayOutputStream;
        }

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

        @Override
        public void setWriteListener(WriteListener listener) {
        }

        @Override
        public void write(int b) throws IOException {
            byteArrayOutputStream.write(b);
        }
    }
}