springboot项目配置拦截器，进行登陆等拦截

新建拦截类：

public class LoginInterceptor implements HandlerInterceptor{
	private static Log logger = LogFactory.getLog(LoginInterceptor.class);
	//handle 前
	@Override
	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {
		
		SysUser user  = (SysUser) request.getSession().getAttribute("user");
		logger.info("***********************执行了拦截器*************************");
		if(user==null) {
　　　　　　　　　　　　　　//未登陆向前端返回数据 
			JsonResult jsonResult = new JsonResult("未登陆");
			jsonResult.setFlag(0);
			String jsonString = JSONObject.toJSONString(jsonResult);
			PrintWriter writer = null;
	        response.setCharacterEncoding("UTF-8");
	        response.setContentType("text/html; charset=utf-8");
	        try {
	            writer = response.getWriter();
	            writer.print(jsonString);
	 
	        } catch (IOException e) {
	            logger.info("未登陆",e);
	        } finally {
	            if (writer != null)
	                writer.close();
	        }
			return false;
		}else {
			return true;
		}
		
	}
　　　　
　　　　//post 时

	@Override
	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		// TODO Auto-generated method stub
		
	}

　　　　//controller 后
	@Override
	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		// TODO Auto-generated method stub
		
	}

}

　　

新建配置类：

对拦截器进行配置 因为springboot本来就是很大程度降低配置的繁琐，所以我觉得再去写配置文件去控制拦截器是否开启就没必要，就在类里面配了一个变量去控制是否开启。

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.WebMvcConfigurerAdapter;
@Configuration
public class MyWebAppConfigurer extends WebMvcConfigurerAdapter {
	//tag 为true 则为开启状态，为false 则为关闭状态
	private boolean tag=false;

	@Override
	public void addInterceptors(InterceptorRegistry registry) {
		
		// addPathPatterns 用于添加拦截规则
        // excludePathPatterns 配置某些路径不拦截
		if(tag==true) {
			InterceptorRegistration addInterceptor  = registry.addInterceptor(new LoginInterceptor());
			addInterceptor.excludePathPatterns("/test");
			addInterceptor.addPathPatterns("/**");
		}else {
			
		}
		
        //如果有多个拦截器
        //InterceptorRegistration addInterceptor2  = registry.addInterceptor(new MyInterceptor2());
		
		super.addInterceptors(registry);
	}
}