Springboot项目使用拦截器方法详解

1. 创建一个拦截器并实现HandlerInterceptor接口

package com.leiyuan.bs.interceptor;

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

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

// 拦截器
public class MyHandlerInterceptor implements HandlerInterceptor {
  /**
   * 拦截（Controller方法调用之前）
   *
   * @param request request
   * @param response response
   * @param o    o
   * @return 通过与否
   * @throws Exception 异常处理
   */
  @Override
  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object
      o) throws Exception {
    // TODO 我这里是通过用户是否登陆进行拦截，我的用户信息存储在session中，名称为userSession，大家可以自行实现
    if (request.getSession().getAttribute("userSession") == null) {
      // 拦截至登陆页面
      request.getRequestDispatcher("/user/toLogin").forward(request, response);
      // false为不通过
      return false;
    }
    // true为通过
    return true;
  }

  // 此方法为处理请求之后调用（调用过controller方法之后，跳转视图之前）
  @Override
  public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o,
              ModelAndView modelAndView) throws Exception {

  }

  // 此方法为整个请求结束之后进行调用
  @Override
  public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse,
                Object o, Exception e) throws Exception {

  }
}

2. 创建一个配置类MyHandlerInterceptorConfig并继承WebMvcConfigurerAdapter类重写addInterceptors(InterceptorRegistry registry)方法

package com.leiyuan.bs;

import com.leiyuan.bs.interceptor.MyHandlerInterceptor;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
// 拦截器配置类
@Component
public class MyHandlerInterceptorConfig extends WebMvcConfigurerAdapter {
  @Override
  public void addInterceptors(InterceptorRegistry registry) {
  	/**
     * 这里的addPathPatterns("/**")为配置需要拦截的方法“/**”代表所有，而后excludePathPatterns("/user/toLogin")等方法为排除哪些方法不进行		 拦截
     */
    registry.addInterceptor(new MyHandlerInterceptor()).addPathPatterns("/**").excludePathPatterns("/user/toLogin").excludePathPatterns
        ("/user/login").excludePathPatterns("/user/toNewUser").excludePathPatterns("/user/newUser");
    super.addInterceptors(registry);
  }
}

3. 启动项目即可看到效果了