在web开发的过程中，为了实现登录权限验证，我们往往需要添加一个拦截器在用户的的请求到达controller层的时候实现登录验证，那么SpringBoot如何添加拦截器呢？
步骤如下：
1.继承WebMvcConfigureAdapter类，覆盖其addInterceptors接口,注册我们自定义的拦截器：
/**
*
* 注册拦截器
* Created by SYSTEM on 2017/8/16.
*/
public class WebAppConfig extends WebMvcConfigurerAdapter { @Override
public void addInterceptors(InterceptorRegistry registry) {
//注册自定义拦截器，添加拦截路径和排除拦截路径
registry.addInterceptor(new InterceptorConfig()).addPathPatterns("api/path/**").excludePathPatterns("api/path/login");
}
}
2.实现HandlerInterceptor接口，重写接口中的三个方法：
public class InterceptorConfig implements HandlerInterceptor{
private static final Logger log = LoggerFactory.getLogger(InterceptorConfig.class);
/**
* 进入controller层之前拦截请求
* @param httpServletRequest
* @param httpServletResponse
* @param o
* @return
* @throws Exception
*/
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
log.info("---------------------开始进入请求地址拦截----------------------------");
HttpSession session = httpServletRequest.getSession();
if(!StringUtils.isEmpty(session.getAttribute("userName"))){
return true;
}
else{
PrintWriter printWriter = httpServletResponse.getWriter();
printWriter.write("{code:0,message:\"session is invalid,please login again!\"}");
return false;
}
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
log.info("--------------处理请求完成后视图渲染之前的处理操作---------------");
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
log.info("---------------视图渲染之后的操作-------------------------0");
}
}
这样我们就可以在用户请求到达controller层实现登录拦截了，所有用户请求都会被拦截，在prehandle方法进行登录判断，返回true则验证通过，否则失败