SpringBoot如何自定义拦截器呢?

HandlerInterceptor的功能

在request被响应之前(请求到达Controller之前)
在request被响应后视图渲染之前
整个request全部结束之后(一般用于请求结束释放资源)

注意事项:
   不能使用拦截器修改request里的内容
    但可以抛异常或return false来结束Request请求的后续执行

实现自定义拦截器方法

package com.java265.myInterceptor;
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;

@Component
public class MyInterceptor implements HandlerInterceptor {

    //请求处理之前Controller之前调用
    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest,
	   HttpServletResponse httpServletResponse, Object o) throws Exception {

        System.out.println("MyInterceptor the requestHandler  before");

        //必须return:true否则请求将不会向下执行
        return true;
    }

    //请求处理之后但视图渲染之前调用
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, 
	   HttpServletResponse httpServletResponse, 
	   Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("MyInterceptor the requestHandler  after");
    }

    //整个请求结束，视图完成渲染之后调用，一般用于释放资源
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, 
	HttpServletResponse httpServletResponse, 
	Object o, Exception e) throws Exception {
        System.out.println("MyInterceptor the view after");
    }
}
 
配置自定义拦截器类：创建一个Java类继承WebMvcConfigurerAdapter，并重写 addInterceptors 方法
将自定义拦截器放入拦截器链中：addInterceptors 方法中添加自己的拦截器类，并指定拦截的URL；
package com.java265.myInterceptor;

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.WebMvcConfigurerAdapter;


@Configuration
public class MyInterceptorConfig extends WebMvcConfigurerAdapter {

    @Autowired
    private MyInterceptor myInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //将自定义拦截器加入拦截器链中，并指定拦截的URl
        registry.addInterceptor(myInterceptor).addPathPatterns("/swagger/*");
    }
}