个人学习系列 - 解决拦截器操作请求参数后台无法获取

由于项目需要使用拦截器对请求参数进行操作，可是请求流只能操作一次，导致后面方法不能再获取流了。

新建SpringBoot项目

1. 新建拦截器WebConfig.java

/**
 * @date: 2023/2/6 11:21
 * @author: zhouzhaodong
 * @description:
 */
@Configuration
public class WebConfig implements WebMvcConfigurer {
    /**
     * 添加Web项目的拦截器
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 对所有访问路径，都通过MyInterceptor类型的拦截器进行拦截
        // 放行登录页，登陆操作，静态资源
        registry.addInterceptor(new MyInterceptor()).addPathPatterns("/**")
                .excludePathPatterns("/", "/login", "/index.html", "/user/login", "/css/**", "/images/**", "/js/**", "/fonts/**");
    }
}

2. 获取请求参数并处理逻辑

/**
 * @date: 2023/2/6 12:46
 * @author: zhouzhaodong
 * @description: 获取请求参数并处理
 */
public class RequestWrapper extends HttpServletRequestWrapper {
    private final Logger logger = LoggerFactory.getLogger(RequestWrapper.class);
    private final byte[] body;

    public RequestWrapper(HttpServletRequest request) {
        super(request);
        String sessionStream = getBodyString(request);
        body = sessionStream.getBytes(StandardCharsets.UTF_8);
    }

    public String getBodyString() {
        return new String(body, StandardCharsets.UTF_8);
    }

    /**
     * @date: 2023/2/6 12:46
     * @author: zhouzhaodong
     * @description: 获取请求Body
     */
    public 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, StandardCharsets.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();
                }
            }
        }
        logger.info("获取body请求参数:" + sb);
        return sb.toString();
    }

    /**
     * @date: 2023/2/6 12:46
     * @author: zhouzhaodong
     * @description: 复制输入流
     */
    public 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();
        }
        return new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
    }

    @Override
    public BufferedReader getReader() {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() {

        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
        return new ServletInputStream() {

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

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

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

            @Override
            public void setReadListener(ReadListener readListener) {

            }
        };
    }
}

3. 实现HandlerInterceptor接口

/**
 * @date: 2023/2/6 11:19
 * @author: zhouzhaodong
 * @description: 实现HandlerInterceptor接口
 */

public class MyInterceptor implements HandlerInterceptor {

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

    /**
     * @date: 2023/2/6 11:19
     * @author: zhouzhaodong
     * @description: 访问控制器方法前执行
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        logger.info("================进入拦截器======================");
        logger.info(new Date() + "--preHandle:" + request.getRequestURL());
        logger.info("***************************【RequestBeginning】***************************");
        logger.info("----------------StartProcessingRequest----------------");
        try {
            long currentTime = System.currentTimeMillis();
            SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
            Date date = new Date(currentTime);
            logger.info("CurrentTime: {}", formatter.format(date));
            logger.info("ResponseTime: {}", (System.currentTimeMillis() - currentTime) + "ms");
            String requestUrl = request.getRequestURI();
            logger.info("RequestURL: {} ", requestUrl);
            logger.info("GetMethod: {}", handler);
            String method = request.getMethod();
            logger.info("Method: {}", method);
            //获取请求参数
            RequestWrapper requestWrapper = new RequestWrapper(request);
            //这里getBodyString()方法无参数
            logger.info("RequestBody: {}", requestWrapper.getBodyString());
        } catch (Exception e) {
            logger.error("MVC业务处理-拦截器异常：", e);
        }
        logger.info("-------------------------End-------------------------");
        return true;
    }

    /**
     * @date: 2023/2/6 12:46
     * @author: zhouzhaodong
     * @description: 访问控制器方法后执行
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
        logger.info(new Date() + "--postHandle:" + request.getRequestURL());
    }

    /**
     * @date: 2023/2/6 12:46
     * @author: zhouzhaodong
     * @description: postHandle方法执行完成后执行，一般用于释放资源
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        logger.info(new Date() + "--afterCompletion:" + request.getRequestURL());
    }
}

4. application.yml

spring:
  main:
    # 当出现相同名字的类进行注册时，准许覆盖注册
    allow-bean-definition-overriding: true

5. 启动类添加@ServletComponentScan注解

6. 新建TestController.java

/**
 * @date: 2023/2/6 12:24
 * @author: zhouzhaodong
 * @description: 测试
 */
@RestController
public class TestController {

    @PostMapping("/one/abc")
    public String abc(@RequestBody User user){
        return user.getName();
    }
}

7. 不进行处理先测试看结果

请求结果：

控制台输出：

可以看出，流被读取了一次然后后台就获取不到了。

8. 通过过滤器获取参数然后传到后面程序中

/**
 * @date: 2023/2/6 12:47
 * @author: zhouzhaodong
 * @description:
 */
@Component
@WebFilter(urlPatterns = "/*", filterName = "channelFilter")
public class ChannelFilter implements Filter {
    private final Logger logger = LoggerFactory.getLogger(ChannelFilter.class);

    @Override
    public void init(FilterConfig filterConfig) {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        logger.info("================进入过滤器======================");
        // 防止流读取一次后就没有了, 所以需要将流继续写出去
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        RequestWrapper requestWrapper = new RequestWrapper(httpServletRequest);
        filterChain.doFilter(requestWrapper, servletResponse);
    }

    @Override
    public void destroy() {

    }
}

9. 流处理后再进行测试

请求结果：

控制台输出：

解决啦！！！

源代码路径

https://github.com/zhouzhaodo...