SpringBoot使用Interceptor拦截器的实例

来源：jb51　　时间：2023/3/20 8:40:15　　对本文有异议

在springboot中使用拦截器也比较简单，实现HandlerInterceptor或者AsyncHandlerInterceptor接口，再从配置里添加一下拦截器就完成了；

AsyncHandlerInterceptor接口继承了HandlerInterceptor，多了一个afterConcurrentHandlingStarted方法：

接口里的方法：

preHandle：在Controller之前执行，可以判断参数，执行的controller方法等，返回值为boolean，返回true继续往下运行（下面的拦截器和controller），否则开始返回操作（执行之前的拦截器返回等操作）；
postHandle：在Controller之后，视图返回前执行，可对ModelAndView进行处理再返回；
afterCompletion：请求完成后执行；
afterConcurrentHandlingStarted：controller返回值是java.util.concurrent.Callable时才会调用该方法并使用新线程运行；

方法执行顺序有两种：

preHandle -> 执行Controller -> postHandle -> afterCompletion；
preHandle -> 执行Controller -> afterConcurrentHandlingStarted -> callable线程执行call()方法 -> 新线程开始preHandle -> postHandle -> afterCompletion；（controller方法返回Callable对象时）

配置拦截器：

实现WebMvcConfigurer接口里的addInterceptors方法，使用参数InterceptorRegistry对象添加自己的拦截器，可以添加指定拦截路径或者去掉某些过滤路径，还可以设置拦截器的优先级order，优先级由小到大，默认0；

多个拦截器的执行顺序：

preHandle方法按照order由小到大顺序，执行完controller后，其他方法则反向顺序，跟过滤器Filter类似；

测试启动类，默认配置：

/**
 * 2023年3月16日下午4:56:23
 */
package testspringboot.test9interceptor;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
 
/**
 * @author XWF
 *
 */
@SpringBootApplication
public class Test9Main {
 
    /**
     * @param args
     */
    public static void main(String[] args) {
        SpringApplication.run(Test9Main.class, args);
    }
 
}

controller类：

/**
 * 2023年3月16日下午4:58:02
 */
package testspringboot.test9interceptor;
 
import java.util.concurrent.Callable;
 
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
/**
 * @author XWF
 *
 */
@RestController
@RequestMapping("/interceptor")
public class Test9Controller {
 
    @RequestMapping("/a")
    public String a(String s) {
        System.out.println(">>>a():" + s);
        return "OK";
    }
    
    @RequestMapping("/b")
    public Callable<String> b() {
        Callable<String> callable = new Callable<String>() {
            @Override
            public String call() throws Exception {
                Thread.sleep(2000);
                System.out.println("call() thread id=" + Thread.currentThread().getId());
                Thread.sleep(2000);
                return "abcdefg";
            }
        };
        System.out.println(">>>b()");
        return callable;
    }
    
}

两个自定义拦截器1和2：

/**
 * 2023年3月16日下午5:14:14
 */
package testspringboot.test9interceptor;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
 
/**
 * @author XWF
 *
 */
public class MyInterceptor1 implements HandlerInterceptor {
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("preHandle 1, handler=" + handler);
        return request.getQueryString().length() < 10 ? true : false; 
    }
    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle 1");
    }
    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("afterCompletion 1");
    }
    
}

/**
 * 2023年3月16日下午5:15:28
 */
package testspringboot.test9interceptor;
 
import java.util.Date;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.AsyncHandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
 
/**
 * @author XWF
 *
 */
@Component
public class MyInterceptor2 implements AsyncHandlerInterceptor {
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("preHandle 2 " + new Date() + " ThreadId=" + Thread.currentThread().getId());
        return true;
    }
    
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle 2");
    }
    
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("afterCompletion 2");
    }
    
    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("afterConcurrentHandlingStarted 2 " + new Date());
    }
    
}

配置拦截器：

/**
 * 2023年3月16日下午5:20:31
 */
package testspringboot.test9interceptor;
 
import javax.annotation.Resource;
 
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
 
/**
 * @author XWF
 *
 */
@Configuration
public class MyInterceptorConfig implements WebMvcConfigurer {
 
    @Resource
    MyInterceptor2 myinterceptor2;
    
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor1())
            .addPathPatterns("/interceptor/a")        //添加拦截路径，两种参数List<String>和String ...
            .excludePathPatterns("/interceptor/b")        //排除路径，两种参数List<String>和String ...
            .order(1);        //设置拦截器顺序，由小到大，默认0
        registry.addInterceptor(myinterceptor2);    //也可以使用spring管理的对象
    }
    
}