SpringBoot2.x整合HandlerInterceptor攔截器（1-定義攔截器）

JAVA && Spring && SpringBoot2.x — 學習目錄

1. 攔截器的基本使用

1.1 攔截器的實現(xiàn)類

  1. 實現(xiàn)Spring的HandlerInterceptor接口；
  2. 繼承實現(xiàn)HandlerInterceptor接口的類，例如：HandlerInterceptorAdapter；

1.2 HandlerInterceptor方法介紹

    boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception;

    void postHandle(
            HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
            throws Exception;

    void afterCompletion(
            HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception;
  • preHandler：業(yè)務(wù)處理器處理請求之前被調(diào)用，對用戶的request進行處理，若返回值為true，則繼續(xù)調(diào)用后續(xù)的攔截器和目標方法；若返回值為false，則終止請求；這里可以加上登錄校驗，權(quán)限攔截等。
  • postHandler：Controller執(zhí)行后但未返回視圖前調(diào)用該方法，這里可以對返回用戶前的模型數(shù)據(jù)進行加工處理。
  • afterCompletion：Controller執(zhí)行后且返回視圖后調(diào)用，可以得到Controller時的異常信息，這里可以記錄操作日志，資源清理等。

1.3 將攔截器加入到MVC中

在SpringBoot 2.0以上， WebMvcConfigurerAdapter已過時，但是WebMvcConfigurerAdapter實際上是WebMvcConfigurer接口的空實現(xiàn)類。故有兩種方法可以實現(xiàn)：推薦使用：implements WebMvcConfigurer

1. @EnableWebMvc + implements WebMvcConfigurer
在擴展類中重寫父類的方法即可，這種方法會屏蔽springboot對SpringMVC的自動配置。
2. implements WebMvcConfigurer
在擴展類中重寫父類的方法即可，這種方法會使用springboot對SpringMVC的自動配置。
3. extends WebMvcConfigurationSupport
在擴展類中重寫父類的方法即可，這種方法會屏蔽springboot對SpringMVC的自動配置。

根據(jù)官方文檔，盡量不要使用@EnableWebMvc注解，因為他會關(guān)閉自動配置。

詳情請了解——SpringBoot中對SpringMVC的自動配置

@Component
public class LogInterceptor implements HandlerInterceptor {
    private final static Logger logger = LoggerFactory.getLogger(LogInterceptor.class);
    //業(yè)務(wù)處理器處理請求之前被調(diào)用，對用戶的request進行處理
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        logger.info("【攔截器】-【已進入攔截器！！】");
        return true;
    }
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
    }
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        
    }
}

@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
    @Autowired
    private LogInterceptor logInterceptor;
    //配置攔截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //指定攔截器，指定攔截路徑
        registry.addInterceptor(logInterceptor).addPathPatterns("/**");
    }
}

2. 攔截器的自定義注解

創(chuàng)建注解類。

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.TYPE, ElementType.METHOD})  ////作用于類、接口等與方法上
@Retention(value = RetentionPolicy.RUNTIME)
public @interface MyLimit {
    int intVal() default 5;
    String stringVal() default "";
}

創(chuàng)建攔截器類-AnnotationInterceptor

@Component
public class AnnotationInterceptor implements HandlerInterceptor {
    private final static Logger logger = LoggerFactory.getLogger(AnnotationInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //判斷當前被攔截的方法是否含有注解
        boolean assignableFromMethod = handler.getClass().isAssignableFrom(HandlerMethod.class);//[額賽額包] 指定的
        logger.info("當前方法上是否有注解" + assignableFromMethod);
        if (assignableFromMethod) {
            //獲取當前方法的自定義注解攔截器的注解
            MyLimit methodAnnotation = ((HandlerMethod) handler).getMethodAnnotation(MyLimit.class);
            logger.info("當前方法的注解：" + methodAnnotation);
            if (methodAnnotation == null) {
                return true;
            }
            //獲取注解上的參數(shù)
            int intVal = methodAnnotation.intVal();
            String stringVal = methodAnnotation.stringVal();
            logger.info("打印注解上的參數(shù)：[intVal={}][stringVal={}]", intVal, stringVal);
        }
        return true;
    }
}

配置攔截器

@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
    @Autowired
    private LogInterceptor logInterceptor;
    @Resource
    private AnnotationInterceptor annotationInterceptor;
    //配置攔截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //指定攔截器，指定攔截路徑
        registry.addInterceptor(logInterceptor).addPathPatterns("/**");
        registry.addInterceptor(annotationInterceptor);
    }
}

使用注解

    @RequestMapping(value = "/get", method = RequestMethod.GET)
    @ResponseBody
    @MyLimit(stringVal = "哈哈，哈哈哈")
    public String getUesr(@RequestParam(value = "str", required = false) Integer integer) {
        try {
            if (integer == 2) {
                throw new RuntimeException("請求地址不合法");
            }
        }catch (Exception e){
            logger.error("請求參數(shù)不合法",e);
        }
        logger.info("請求參數(shù)：str={}",integer);
        SysQuartzJobConfig sysQuartzJobConfig = sysQuartzJobConfigMapper.selectByPrimaryKey(integer);
        return JSON.toJSONString(sysQuartzJobConfig);
    }

效果：

MyPrefix 16591 INFO com.Interceptor.impl.AnnotationInterceptor - 當前方法上是否有注解true
MyPrefix 16591 INFO com.Interceptor.impl.AnnotationInterceptor - 當前方法的注解：@com.Interceptor.annotation.MyLimit(intVal=5, stringVal=哈哈，哈哈哈)
MyPrefix 16592 INFO com.Interceptor.impl.AnnotationInterceptor - 打印注解上的參數(shù)：[intVal=5][stringVal=哈哈，哈哈哈]

3. 獲取請求參數(shù)解決java.io.IOException: Stream closed

在攔截器中通過request.getInputStream();獲取body中的信息后，此時在Controller中使用@RequestBody注解獲取參數(shù)出現(xiàn)異常。

流關(guān)閉異常出現(xiàn)原因分析

IO（1）Java-BIO體系學習

  1. 輸入流中含有一個“隱式指針”記錄當前流讀取的位置，故一旦我們在攔截器中將讀取InputStream，那么后續(xù)無法使用@RequestBody注解。
  2. 可以在【攔截器】之前使用【過濾器】，包裝request請求，重寫getInputStream()方法；
  3. 將數(shù)據(jù)保存到內(nèi)存Byte[]中，使用ByteArrayInputStream進行操作。

引入依賴

在springboot中，無需引入。

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-core</artifactId>
    <version>8.5.15</version>
</dependency>

新建攔截器

@Component
public class LogInterceptor implements HandlerInterceptor {

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

    //業(yè)務(wù)處理器處理請求之前被調(diào)用，對用戶的request進行處理
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        logger.info("【攔截器】-【已進入攔截器??！】");
        logger.info("【攔截器】-request的類型{}", request.getClass());
        String bodyString = HttpHelper.getBodyString(request);
        logger.info("bodyString的值：" + bodyString);
        return true;
    }
}

新建過濾器

public class HttpServletRequestReplacedFilter implements Filter {

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

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

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        logger.info("【過濾器】-【已進入過濾器！】");
        ServletRequest requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
        chain.doFilter(requestWrapper, response);
    }

    @Override
    public void destroy() {

    }
}

包裝request

public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
    private final static Logger logger = LoggerFactory.getLogger(BodyReaderHttpServletRequestWrapper.class);

    private final byte[] body;

    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) {
        super(request);
        //獲取到請求體
        logger.info("【過濾器】-【獲取請求的body信息】");
        body = HttpHelper.getBodyString(request).getBytes(Charset.forName("UTF-8"));
    }

    //重寫方法
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {
        //節(jié)點流
        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
        return new ServletInputStream() {
            @Override
            public boolean isFinished() {
                return false;
            }

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

            @Override
            public void setReadListener(ReadListener listener) {
                //監(jiān)聽
                logger.info("【攔截器】-【BodyReaderHttpServletRequestWrapper ReadListener:{}】", this);
            }

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

讀取Body的工具類

public class HttpHelper {
    private final static Logger logger = LoggerFactory.getLogger(HttpHelper.class);
    public static String getBodyString(HttpServletRequest request) {

        StringBuffer sb = new StringBuffer();
        InputStream inputStream;
        BufferedReader bufferedReader;
        try {
            //將數(shù)據(jù)保存到數(shù)組中，每次讀取的時候，都讀取一遍
            inputStream = request.getInputStream();
            //將字節(jié)數(shù)組當做輸出的目的地
            //字節(jié)流轉(zhuǎn)換為字符流（處理流）
            bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
            String line = "";
            while ((line = bufferedReader.readLine()) != null) {
                sb.append(line);
            }
        } catch (Exception e) {
            logger.error("數(shù)據(jù)讀取異常", e);
        }
        return sb.toString();
    }
}

攔截器過濾器加入到容器中

@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
    @Autowired
    private LogInterceptor logInterceptor;
//    @Resource
//    private AnnotationInterceptor annotationInterceptor;
    //配置攔截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //指定攔截器，指定攔截路徑
        registry.addInterceptor(logInterceptor).addPathPatterns("/**");
//        registry.addInterceptor(annotationInterceptor);
    }

    @Bean
    public FilterRegistrationBean httpServletRequestReplacedRegistration() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        registration.setFilter(new HttpServletRequestReplacedFilter());
        registration.addUrlPatterns("/*");
        registration.addInitParameter("paramName", "paramValue");
        registration.setName("httpServletRequestReplacedFilter");
        registration.setOrder(1);
        return registration;
    }
}

執(zhí)行日志

2019-07-02 16:40:07,598 INFO [22059] [http-nio-8080-exec-1] [] (DirectJDKLog.java:173): Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-07-02 16:40:07,598 INFO [22059] [http-nio-8080-exec-1] [] (FrameworkServlet.java:524): Initializing Servlet 'dispatcherServlet'
2019-07-02 16:40:07,610 INFO [22071] [http-nio-8080-exec-1] [] (FrameworkServlet.java:546): Completed initialization in 12 ms
2019-07-02 16:40:07,620 INFO [22081] [http-nio-8080-exec-1] [] (HttpServletRequestReplacedFilter.java:22): 【過濾器】-【已進入過濾器！】
2019-07-02 16:40:07,623 INFO [22084] [http-nio-8080-exec-1] [] (BodyReaderHttpServletRequestWrapper.java:26): 【過濾器】-【獲取請求的body信息】
2019-07-02 16:40:07,636 INFO [22097] [http-nio-8080-exec-1] [] (LogInterceptor.java:24): 【攔截器】-【已進入攔截器??！】
2019-07-02 16:40:07,636 INFO [22097] [http-nio-8080-exec-1] [] (LogInterceptor.java:25): 【攔截器】-request的類型class com.filter.BodyReaderHttpServletRequestWrapper
2019-07-02 16:40:07,638 INFO [22099] [http-nio-8080-exec-1] [] (LogInterceptor.java:27): bodyString的值：{"age":"12","name":"liming"}
2019-07-02 16:40:07,797 INFO [22258] [http-nio-8080-exec-1] [] (UserController.java:41): 請求參數(shù)：str={"age":"12","name":"liming"}
最后編輯于 ：
?著作權(quán)歸作者所有,轉(zhuǎn)載或內(nèi)容合作請聯(lián)系作者
【社區(qū)內(nèi)容提示】社區(qū)部分內(nèi)容疑似由AI輔助生成，瀏覽時請結(jié)合常識與多方信息審慎甄別。
平臺聲明：文章內(nèi)容（如有圖片或視頻亦包括在內(nèi)）由作者上傳并發(fā)布，文章內(nèi)容僅代表作者本人觀點，簡書系信息發(fā)布平臺，僅提供信息存儲服務(wù)。

相關(guān)閱讀更多精彩內(nèi)容

友情鏈接更多精彩內(nèi)容