springboot拦截器实例

在上一篇文章主要讲述了过滤器，也提到了spring框架适合使用拦截器，所以就整理了一下用到的案例。

在springboot2.0以后要继承HandlerInterceptorAdapter，2.0之前的版本请自行百度。

具体如下：

public class RequestInterceptor extends HandlerInterceptorAdapter {
    private static Logger logger = Logger.getLogger(RequestInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request,
                             HttpServletResponse response, Object handler) throws Exception {

        Boolean flag = false;

        System.out.println("preHandle start...");
        String token;
        PrintWriter writer = null;
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");
        //获取header的token进行认证
        if (request.getHeader("token") != null || !"".equals(request.getHeader("token"))){
            token = request.getHeader("token");

            //进行token校验
            Map<String, String> params = new HashMap<>();
            params.put("access_token", token);
             //todo:校验需要访问的url，以及你的业务

              try{
                    writer = response.getWriter();
                    writer.print("url的返回结果");

                } catch (IOException e) {
                    logger.error("response error",e);
                } finally {
                    if (writer != null)
                        writer.close();
                }

        }else {
            //没有token处理
            writer = response.getWriter();
            String error = "用户未登录";
            writer.print(error);

        }

        return flag;

    }
}

同样，也需要配置@Configuration

@Configuration
public class InterceptorConfig extends WebMvcConfigurationSupport {
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new         RequestInterceptor()).addPathPatterns("/*").excludePathPatterns("/api/Login/UserLogin");
        super.addInterceptors(registry);
    }
}

同时也不要忘记在Application加上@ComponentScan。

最后，在你请求访问的时候，拦截器会拦截你所要拦截的请求，达到你想要的结果。