Spring 拦截器 学习
拦截器, 技术java反射技术, 不依赖Spring容器, 可以使用 Spring 容器管理的bean.
客户端发起请求到 DispatcherServlet , 然后根据 HandlerMapping 匹配处理器, 返回一个 HandlerExecution 对象, 包含 处理器 和 拦截器, 这里的拦截器会对处理器进行拦截, 通过拦截器可以增强处理器的功能.
1. 创建拦截器, 实现 HandlerInterceptor 接口
package com.codingos.springboot.test.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
public class Interceptor1 implements HandlerInterceptor {
/**
* 在 controller 方法之前执行, 返回false则结束, 返回true则继续下一步.
*/
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println("****** 处理器前方法 *******");
return true;
// request.getRequestDispatcher("/file/uploadPage").forward(request, response);
// return false;
}
/**
* 在处理器方法之后, 视图渲染之前执行.
*/
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println("****** 处理器后方法 *******");
HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
}
/**
* 在视图渲染之后执行
*/
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println("****** 处理器完成后方法 *******");
HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
}
}package com.codingos.springboot.test.interceptor;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
public class MultiInterceptor1 implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
System.out.println(this.getClass().getName() + "处理器前方法");
return true;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
System.out.println(this.getClass().getName() + "处理器后方法");
HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
System.out.println(this.getClass().getName() + "处理器完成后方法");
HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
}
}2. 注册拦截器, springboot 主类 实现 WebMvcConfigurer
@SpringBootApplication
public class SpringBootTestApplication implements WebMvcConfigurer{
/**
* 注册拦截器
*/
@Override
public void addInterceptors(InterceptorRegistry registry) {
// registry.addInterceptor(new Interceptor1()).addPathPatterns("/interceptor/*");
registry.addInterceptor(new MultiInterceptor1()).addPathPatterns("/interceptor/*");
registry.addInterceptor(new MultiInterceptor2()).addPathPatterns("/interceptor/*");
registry.addInterceptor(new MultiInterceptor3()).addPathPatterns("/interceptor/*");
}
public static void main(String[] args) {
SpringApplication.run(SpringBootTestApplication.class, args);
}
}3. 多个拦截器的顺序
com.codingos.springboot.test.interceptor.MultiInterceptor1处理器前方法
com.codingos.springboot.test.interceptor.MultiInterceptor2处理器前方法
com.codingos.springboot.test.interceptor.MultiInterceptor3处理器前方法
执行处理器逻辑
com.codingos.springboot.test.interceptor.MultiInterceptor3处理器后方法
com.codingos.springboot.test.interceptor.MultiInterceptor2处理器后方法
com.codingos.springboot.test.interceptor.MultiInterceptor1处理器后方法
视图渲染
com.codingos.springboot.test.interceptor.MultiInterceptor3处理器完成后方法
com.codingos.springboot.test.interceptor.MultiInterceptor2处理器完成后方法
com.codingos.springboot.test.interceptor.MultiInterceptor1处理器完成后方法本文参与 腾讯云自媒体分享计划，分享自作者个人站点/博客。
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