SpringBoot拦截器

SpringBoot拦截器

 拦截器会对处理器进行拦截，这趟通过拦截器可以增强处理器的功能。

开发拦截器

 所有的拦截器都需要实现HandlerInterceptor接口，在继承HandlerInterceptor有三个拦截器是经常使用的：
　　1.preHandle在业务处理器处理请求之前被调用
　　2.postHandle在业务处理器处理请求执行完成后,生成视图之前执行
　　3.afterCompletion在DispatcherServlet完全处理完请求后被调用该节都定义如下：

package com.example.demo.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @ Author  wjw
 * @ Date  2019-08-21
 */
public class Interceptor1 implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handle) throws Exception {
        System.out.println("处理器前的方法");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handle, ModelAndView modelAndView) throws Exception {
        System.out.println("处理器后的方法");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handle, Exception ex) throws Exception {
        System.out.println("处理器完成的方法");
    }

}

注册拦截器

package com.example.demo;

import com.example.demo.interceptor.Interceptor1;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
@SpringBootApplication
public class DemoApplication implements WebMvcConfigurer {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 注册拦截器到 springmvc 中，然后他会返回一个拦截器的注册
        InterceptorRegistration ir = registry.addInterceptor(new Interceptor1());
        // 指定拦截器的匹配模式，限制拦截器的拦截请求
        ir.addPathPatterns("/interceptor/*");
    }

}

 拦截器控制

package com.example.demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @ Author  wjw
 * @ Date  2019-08-21
 */
@RestController
@RequestMapping("/interceptor")
public class InterceptorController {
    @RequestMapping("/start")
    public String start() {
        System.out.println("执行器处理逻辑");
        return "hello world!";
    }
}