Spring/SpringBoot 过滤器修改、获取http 请求request中的参数 和 response返回值，比如修改请求体和响应体的字符编码

通过自定义filter，RequestWrapper，ResponseWrapper 处理请求和响应数据，比如修改请求体和响应体的字符编码

1.request 和 response 中的数据都是 存在流中的（缓存中）获取一次就没有了，需要重新写回去。所以需要两个包装类分别继承HttpServletRequestWrapper 和 HttpServletResponseWrapper 对 request和response进行包装，从中获取数据。

package com.hoau.monitor.servlet;

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

public class RequestWrapper extends HttpServletRequestWrapper {
    private final String body;

    public RequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        StringBuilder stringBuilder = new StringBuilder();
        BufferedReader bufferedReader = null;
        try {
                InputStream inputStream = request.getInputStream();
            if (inputStream != null) {
                bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
                char[] charBuffer = new char[128];
                int bytesRead = -1;
                while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
                    stringBuilder.append(charBuffer, 0, bytesRead);
                }
            } else {
                stringBuilder.append("");
            }
        } catch (IOException ex) {
            throw ex;
        } finally {
            if (bufferedReader != null) {
                try {
                    bufferedReader.close();
                } catch (IOException ex) {
                    throw ex;
                }
            }
        }
        body = stringBuilder.toString();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes());
        ServletInputStream servletInputStream = new ServletInputStream() {
            public boolean isFinished() {
                return false;
            }

            public boolean isReady() {
                return false;
            }

            public void setReadListener(ReadListener readListener) {
            }

            public int read() throws IOException {
                return byteArrayInputStream.read();
            }
        };
        return servletInputStream;

    }

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

    public String getBody() {
        return this.body;
    }

}

package com.hoau.monitor.servlet;

import javax.servlet.ServletOutputStream;
import javax.servlet.WriteListener;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import java.io.*;

/**
 * @param
 * @author 
 * @create 2019-06-10 13:31
 * @return
 * @description ：
 */
public class ResponseWrapper extends HttpServletResponseWrapper {

    private ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    private HttpServletResponse response;
    private PrintWriter pwrite;

    public ResponseWrapper(HttpServletResponse response) {
        super(response);
        this.response = response;
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        // 将数据写到 byte 中
        return new MyServletOutputStream(bytes);
    }

    /**
     * 重写父类的 getWriter() 方法，将响应数据缓存在 PrintWriter 中
     */
    @Override
    public PrintWriter getWriter() throws IOException {
        try {
            pwrite = new PrintWriter(new OutputStreamWriter(bytes, "utf-8"));
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return pwrite;
    }

    /**
     * 获取缓存在 PrintWriter 中的响应数据
     *
     * @return
     */
    public byte[] getBytes() {
        if (null != pwrite) {
            pwrite.close();
            return bytes.toByteArray();
        }

        if (null != bytes) {
            try {
                bytes.flush();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return bytes.toByteArray();
    }

    class MyServletOutputStream extends ServletOutputStream {
        private ByteArrayOutputStream ostream;

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

        @Override
        public void write(int b) throws IOException {
            ostream.write(b); // 将数据写到 stream　中
        }

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

        @Override
        public void setWriteListener(WriteListener listener) {

        }
    }

}

自定义Filter,主要重写doFilter方法，在doFilter方法中通过包装类RequestWrapper，ResponseWrapper可以获取或修改请求和响应体内容

package com.hoau.monitor.filter;

import com.alibaba.dubbo.config.annotation.Reference;
import com.alibaba.fastjson.JSONObject;
import com.hoau.common.exception.PSBCommonException;
import com.hoau.monitor.entity.MonitorData;
import com.hoau.monitor.facade.IhoauMonitorDataFacade;
import com.hoau.monitor.servlet.RequestWrapper;
import com.hoau.monitor.servlet.ResponseWrapper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerMapping;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@Component
@WebFilter(urlPatterns = {"/psb/*"}, filterName = "monitorDataFilter")
public class MonitorDataFilter implements Filter {


    @Reference(group = "HoauMonitorFacadeServiceImpl")
    @Qualifier("ihoauMonitorDataServiceImpl")
    IhoauMonitorDataFacade ihoauMonitorDataServiceImpl;

    Log log = LogFactory.getLog(MonitorDataFilter.class);

    private MonitorData monitorData;

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

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //此处可设置http请求和响应的字符编码格式
        servletRequest.setCharacterEncoding("gbk");
        servletResponse.setCharacterEncoding("gbk");
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        HttpServletResponse httpServletResponse = (HttpServletResponse) servletResponse;
        RequestWrapper requestWrapper = new RequestWrapper(httpServletRequest);
        ResponseWrapper responseWrapper = new ResponseWrapper(httpServletResponse);

        filterChain.doFilter(requestWrapper, responseWrapper);

        monitorData = new MonitorData();
        String params = null;
        String paramGet = null;
        String paramVar = null;
        String val = null;
//        String meth = httpServletRequest.getMethod();

        // 获取参数的方式实际跟接收方式相关（@RequestBody @RequestParam @PathVariable），多种注解一块用时参数拼接？
        // 与请求方式无直接关系(post get put delete)
        params = requestWrapper.getBody();
        paramGet = JSONObject.toJSONString(httpServletRequest.getParameterMap());
        paramVar = JSONObject.toJSONString(httpServletRequest.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE));
        if (!"{}".equals(paramGet)&& !"null".equals(paramGet)) {
            params = params + paramGet;
        }
        if (!"{}".equals(paramVar) && !"null".equals(paramVar)) {
            params = params + paramVar;
        }
        log.info("========1.请求参数：" + params);

        monitorData.setInterAddress(httpServletRequest.getRequestURL().toString());
        monitorData.setAccAccount("");
        monitorData.setAccIP(httpServletRequest.getRemoteAddr());
        monitorData.setAccParams(params);
        monitorData.setInterType("");
		
        byte[] bytes = responseWrapper.getBytes();
        val = new String(bytes, "UTF-8");
        monitorData.setRetVal(JSONObject.toJSONString(val));
        log.info("========2.返回值：" + val);
        //将数据 再写到 response 中
        byte[] gbks = val.getBytes("gbk");//这里编码转换操作，这里转换的一定要与接口响应的编码相同
        servletResponse.setContentLength(gbks.length);//这一步一定要有，否则字节数组长度不够会造成线程一直等待而阻塞
        servletResponse.getOutputStream().write(gbks);
        servletResponse.getOutputStream().flush();
        servletResponse.getOutputStream().close();

        try {
            ihoauMonitorDataServiceImpl.addMonitorData(monitorData);
        } catch (PSBCommonException e) {
            e.printStackTrace();
        }

    }

    @Override
    public void destroy() {

    }
}

除了filter 也可以通过切面（配合注解）获取和修改 ServletRequest , ServletResponse ,及请求和响应数据

package com.hoau.common.auth;

import java.lang.annotation.*;

/**
 * @author : 
 * @create : 2019-07-25 10:24
 * @description ：监控注解 应用此注解时，请求的第一个参数必须是 HttpServletRequest
 */
@Documented
@Target({ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface HoauMonitorAnnotation {
}

package com.hoau.common.auth;

import com.alibaba.fastjson.JSONObject;
import com.hoau.common.entity.MonitorData;
import com.hoau.common.servlet.RequestWrapper;
import com.hoau.common.servlet.ResponseWrapper;
import com.hoau.common.util.HttpUtils;
import com.hoau.common.util.JsonUtils;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.HandlerMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.time.Instant;
import java.time.OffsetDateTime;
import java.time.ZoneOffset;
import java.util.HashMap;
import java.util.Map;

/**
 * @author : xilipeng
 * @create : 2019-07-25 10:25
 * @description ：HoauMonitorAnnotation 监控切面
 */
@Aspect
@Order(0)//监控模块优先级必须高于 auth 校验模块，否则安全校验不通过时会是监控通知不执行
@Component
public class MonitorAspect {

    @Value("${monitor.url}")
    protected String monitorUrl;

    @Pointcut("execution(public * com.hoau.*.controller.*.*(..)) && "
            + "@annotation(com.hoau.common.auth.HoauMonitorAnnotation)")
    public void monitorPointcut() {
    }

    @Around("monitorPointcut()")
    public Object monitorAdvice(ProceedingJoinPoint pjp) throws IOException {
        System.out.println("========> system into MonitorAspect ");
        Object result = null;
        Object[] args = pjp.getArgs();
//        BackObject backObject = new BackObject();
        MonitorData monitorData = new MonitorData();
        try {
            //获取请求中的 HttpServletRequest
            ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
            HttpServletRequest httpServletRequest = requestAttributes.getRequest();
            HttpServletResponse response = requestAttributes.getResponse();
//            PrintWriter writer = response.getWriter();
//            HttpEncodingAutoConfiguration httpEncodingAutoConfiguration;
//            ServletOutputStream outputStream = response.getOutputStream();
//            outputStream.
            ResponseWrapper responseWrapper = new ResponseWrapper(response);
            byte[] bytes =responseWrapper.getBytes();

            if (null != httpServletRequest) {
                //获取请求参数
                RequestWrapper requestWrapper = new RequestWrapper(httpServletRequest);
                String params = requestWrapper.getBody();
                String paramGet = JSONObject.toJSONString(httpServletRequest.getParameterMap());

                if (!"{}".equals(paramGet) && !"null".equals(paramGet)) {
                    params += paramGet;
                }
                //获取接口路径
                String uri = httpServletRequest.getRequestURI().toString();
//              String meth = httpServletRequest.getMethod();

                // 获取参数的方式实际跟接收方式相关（@RequestBody @RequestParam @PathVariable），多种注解一块用时参数拼接？
                // 与请求方式无直接关系(post get put delete)
                Map<String, Object> pathVariables = (HashMap<String, Object>) httpServletRequest.getAttribute(HandlerMapping.URI_TEMPLATE_VARIABLES_ATTRIBUTE);

                if (null != pathVariables && !pathVariables.isEmpty()) {

                    String paramVar = JSONObject.toJSONString(pathVariables);
                    params += paramVar;

                    for (String key : pathVariables.keySet()) {
                        String val = "/" + pathVariables.get(key).toString();
                        uri = uri.replace(val, "");
                    }
                }
                monitorData.setInterAddress(uri);
                System.out.println("========1.接口地址：" + uri);
                monitorData.setAccAccount("");
                monitorData.setAccIP(httpServletRequest.getRemoteAddr());
                //存入 ES 的时间
                OffsetDateTime offsetDateTime = Instant.now().atOffset(ZoneOffset.ofHours(8));//2019-08-22T11:49:53.054+08:00
                monitorData.setAccTime(offsetDateTime.toString());
                System.out.println("========Instant.now().atOffset(ZoneOffset.ofHours(8))：" + offsetDateTime.toString());
                monitorData.setAccParams(params);
                System.out.println("========2.请求参数：" + params);
                monitorData.setInterType("");
            } else if (null != args) {//如果未获取到 HttpServletRequest 就只保存请求参数和结果 和请求时间
                //存入 ES 的时间
                OffsetDateTime offsetDateTime = Instant.now().atOffset(ZoneOffset.ofHours(8));//2019-08-22T11:49:53.054+08:00
                monitorData.setAccTime(offsetDateTime.toString());
                monitorData.setAccParams(JsonUtils.toJson(args));
                System.out.println("========1.接口地址：请求参数中未获取到  httpServletRequest");
                System.out.println("========2.请求参数：" + JsonUtils.toJson(args));
            }

            result = pjp.proceed();
        } catch (Throwable e) {
            e.printStackTrace();
//            backObject.setBackStatusCode(RestErrorCodeConstants.STATUS_SYSTEM_ERROR);
//            backObject.setBackStatusStr(RestErrorCodeConstants.STATUS_SYSTEM_ERROR_INFO + e.getMessage());
//            result = JsonUtils.toJson(backObject);
        }

        monitorData.setRetVal(JSONObject.toJSONString(result));
        System.out.println("========3.返回值：" + JSONObject.toJSONString(result));
        try {
            HttpUtils.sendPostRequest(monitorUrl, JsonUtils.toJson(monitorData), "form");
        } catch (Exception e) {
            System.out.println("========监控添加失败：" + e.getMessage());
            e.printStackTrace();
        }
        System.out.println("========> system out MonitorAspect ");
        return result;
    }
}

使用切面也需要filter文章来源地址https://www.toymoban.com/news/detail-557755.html

package com.hoau.common.filter;

import com.hoau.common.servlet.RequestWrapper;
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 javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * @author : 
 * @create : 2019-09-01 16:23
 * @description ：
 */
@Component//在 common 包中需要加上此注解，否则扫描不到
@WebFilter(urlPatterns = {"/*"}, filterName = "requestFilter")
public class RequestFilter implements Filter {
    private static Logger log = LoggerFactory.getLogger(RequestFilter.class);


    @Override
    public void destroy() {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;

        RequestWrapper requestWrapper = new RequestWrapper(httpServletRequest);
//        ResponseWrapper responseWrapper = new ResponseWrapper(httpServletResponse);

        filterChain.doFilter(requestWrapper, httpServletResponse);
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {

    }


}

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