关于java:个人学习系列-解决拦截器操作请求参数后台无法获取

因为我的项目须要应用拦截器对申请参数进行操作，可是申请流只能操作一次，导致前面办法不能再获取流了。

新建 SpringBoot 我的项目

1. 新建拦截器 WebConfig.java

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

2. 获取申请参数并解决逻辑

/**
 * @date: 2023/2/6 12:46
 * @author: zhouzhaodong
 * @description: 获取申请参数并解决
 */
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: 获取申请 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 申请参数:" + sb);
        return sb.toString();}

    /**
     * @date: 2023/2/6 12:46
     * @author: zhouzhaodong
     * @description: 复制输出流
     */
    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: 拜访控制器办法前执行
     */
    @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);
            // 获取申请参数
            RequestWrapper requestWrapper = new RequestWrapper(request);
            // 这里 getBodyString() 办法无参数
            logger.info("RequestBody: {}", requestWrapper.getBodyString());
        } catch (Exception e) {logger.error("MVC 业务解决 - 拦截器异样：", e);
        }
        logger.info("-------------------------End-------------------------");
        return true;
    }

    /**
     * @date: 2023/2/6 12:46
     * @author: zhouzhaodong
     * @description: 拜访控制器办法后执行
     */
    @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 办法执行实现后执行，个别用于开释资源
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {logger.info(new Date() + "--afterCompletion:" + request.getRequestURL());
    }
}

4. application.yml

spring:
  main:
    # 当呈现雷同名字的类进行注册时，准许笼罩注册
    allow-bean-definition-overriding: true

5. 启动类增加 @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. 不进行解决先测试看后果

申请后果：

控制台输入：

能够看出，流被读取了一次而后后盾就获取不到了。

8. 通过过滤器获取参数而后传到前面程序中

/**
 * @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 ======================");
        // 避免流读取一次后就没有了, 所以须要将流持续写出去
        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
        RequestWrapper requestWrapper = new RequestWrapper(httpServletRequest);
        filterChain.doFilter(requestWrapper, servletResponse);
    }

    @Override
    public void destroy() {}
}

9. 流解决后再进行测试

申请后果：

控制台输入：

解决啦！！！

源代码门路

https://github.com/zhouzhaodo…