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SpringBoot自定义拦截器以及多个拦截器执行顺序

news 来源：原创 2025/4/25 5:34:36

一 springboot自定义拦截器

1.1 了解拦截器

springboot所有的拦截器都实现/继承自HandlerInterceptor接口。如果想要编写一个自定义拦截器，就需要实现/继承HandlerInterceptor接口或其子接口/实现类。下图所示为Spring MVC中拦截器的类图
在这里插入图片描述
HandlerInterceptor接口的源码如下，包含3个默认实现（Java 8）的方法——preHandle、postHandle和afterCompletion

public interface HandlerInterceptor {//处理器执行前被调用default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {return true;}//处理器执行后，视图渲染前被调用default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {}//视图渲染完成后被调用default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {}
}

先自定义一个最简单、纯净的拦截器，也就是直接实现HandlerInterceptor 接口。新建一个 LogInterceptor 类并实现HandlerInterceptor接口

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;@Slf4j
@Component
public class LogInterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {log.info("preHandle");return true;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {log.info("postHandle");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {log.info("afterCompletion");}
}

在3个方法中分别添加了一条日志打印代码。新建一个WebConfigurer类并实现WebMvcConfigurer接口，用于注册自定义的拦截器：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;@Configuration
public class WebConfigurer implements WebMvcConfigurer {@Autowiredprivate LogInterceptor logInterceptor;
//    @Autowired
//    private TimeInterceptor timeInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(logInterceptor);
//      registry.addInterceptor(timeInterceptor);}
}

在HelloController类的hello方法中添加一条日志打印代码：

@slf4j
@RestController
public class HelloController {@GetMapping("/hello")public String hello() {log.info("hello");return "Hello Spring Boot";}
}

接下来启动工程，并访问http://localhost：8080/hello，会在控制台看到如下输出：
在这里插入图片描述
这代表我们自定义的拦截器成功了！

1.2 拦截器执行流程

从控制台的日志输出中，我们可以大概看出拦截器的执行流程。通过下图，我们可以更清晰地了解拦截器的执行流程。
在这里插入图片描述

执行preHandle方法。该方法会返回一个布尔值。如果为false，则结束本次请求；如果为true，则继续本次请求。
执行处理器逻辑，也就是Controller。
执行postHandle方法。
执行afterCompletion方法。

二多个拦截器

在实际应用中，通常需要多个拦截器一起配合使用才能满足我们的需求。了解了单个拦截器的执行流程后，接下来看看多个拦截器组合起来是如何运转的：是执行完一个再执行下一个，还是嵌套执行，抑或是其他的方式呢？下面我们来一探究竟。

再创建一个拦截器，用来记录程序执行消耗的时间，创建一个TimeInterceptor类，同样实现HandlerInterceptor接口，代码如下：


import lombok.extern.slf4j.Slf4j;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.time.Duration;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;@Slf4j
//@Component
public class TimeInterceptor implements HandlerInterceptor {private final ThreadLocal<LocalTime> threadLocalStart = new ThreadLocal<>();private final ThreadLocal<LocalTime> threadLocalEnd = new ThreadLocal<>();private final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("HH:mm:ss:SSS");// 记录开始时间@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {LocalTime startTime = LocalTime.now();threadLocalStart.set(startTime);log.info("开始时间：{}", startTime.format(formatter));return true;}// 记录结束时间@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {LocalTime endTime = LocalTime.now();threadLocalEnd.set(endTime);log.info("结束时间：{}", endTime.format(formatter));}// 计算接口执行时间@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {LocalTime startTime = threadLocalStart.get();LocalTime endTime = threadLocalEnd.get();log.info("接口执行时间：{} 毫秒", Duration.between(startTime, endTime).getNano() / 1000000);}
}

注册拦截器

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;@Configuration
public class WebConfigurer implements WebMvcConfigurer {@Autowiredprivate LogInterceptor logInterceptor;@Autowiredprivate TimeInterceptor timeInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(logInterceptor);registry.addInterceptor(timeInterceptor);}
}