@Component
public class MyZuulFilter extends ZuulFilter{

	//shouldFilter()方法表示是否执行该过滤器，也可以说是该过滤器的一个开关
	@Override
	public boolean shouldFilter() {
		//此方法可以根据请求的url进行判断是否需要拦截
		return true;
	}

	//run()方法是过滤器的具体逻辑。在该函数中，我们可以实现自定义的过滤逻辑，来确定是否要拦截当前的请求，不对其进行后续的路由，或是在请求路由返回结果之后，对处理结果做一些加工等
	//获取请求的url，如果该url携带了token，我们就让他通过，否则直接拦截
	@Override
	public Object run() throws ZuulException {
		//获取请求的上下文类 注意是：com.netflix.zuul.context包下的
		RequestContext ctx = RequestContext.getCurrentContext();
		HttpServletRequest request = ctx.getRequest();
		ctx.addZuulResponseHeader("Content-type", "text/json;charset=UTF-8");
		ctx.getResponse().setCharacterEncoding("UTF-8");
		System.out.println("请求地址:"+request.getRequestURI());
		String token = request.getParameter("token");
		String msg="请求成功!";
		if(token==null) {
			//使其不进行转发
		   ctx.setSendZuulResponse(false);
		   msg="请求失败！原因是token为空！";
		   ctx.setResponseBody(msg);
		   ctx.setResponseStatusCode(HttpStatus.UNAUTHORIZED.value());
		   //或者添加一个额外参数也可以 传递参数可以使用
//		   ctx.set("checkAuth",false);
		}
		System.out.println(msg);
		return msg;
	}

	//设置为前置过滤器，在请求被路由之前调用
	@Override
	public String filterType() {
		//前置过滤器
		return FilterConstants.PRE_TYPE;
	}

	@Override
	public int filterOrder() {
		//执行顺序  0 靠前执行 在spring cloud zuul提供的pre过滤器之后执行，默认的是小于0的。	
		//除了参数校验类的过滤器 一般上直接放在 PreDecoration前
		//即：PRE_DECORATION_FILTER_ORDER - 1;
		//常量类都在：org.springframework.cloud.netflix.zuul.filters.support.FilterConstants 下
		return 0;
	}
	
	//将该过滤类使用Bean注解使其生效
	@Bean
	public MyZuulFilter zuulFilter() {
	    return new MyZuulFilter();
	}

}

@Component
public class MyErrorFilter extends SendErrorFilter{

	@Override
	public Object run() {
		String msg="请求失败!";
		//重写 run方法		
		try{
			RequestContext ctx = RequestContext.getCurrentContext();
			//直接复用异常处理类
			ExceptionHolder exception = findZuulException(ctx.getThrowable());
			System.out.println("错误信息:"+exception.getErrorCause());
			msg+="error:"+exception.getErrorCause();
			System.out.println("msg:"+msg);

			HttpServletResponse response = ctx.getResponse();
			//设置编码
			response.setCharacterEncoding("UTF-8");
			response.getOutputStream().write(msg.getBytes());           	 
		}catch (Exception ex) {
			ex.printStackTrace();
			ReflectionUtils.rethrowRuntimeException(ex);
		}
		return msg;
	}
	
	/**
	 *  自定义异常过滤器
	 */
	@Bean
	//@ConditionalOnProperty(name="zuul.SendErrorFilter.error.disable")
	public MyErrorFilter errorFilter() {
	    return new MyErrorFilter();
	}
	

}

@Component
public class MyFallback implements FallbackProvider {
    private static  final  String SERVER_NAME="springcloud-zuul-filter-server2";

    @Override
    public String getRoute() {
        return SERVER_NAME;
    }

    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {

        //标记不同的异常为不同的http状态值
        if (cause instanceof HystrixTimeoutException) {
            return response(HttpStatus.GATEWAY_TIMEOUT);
        } else {
            //可继续添加自定义异常类
            return response(HttpStatus.INTERNAL_SERVER_ERROR);
        }
    }
    //处理
    private ClientHttpResponse response(final HttpStatus status) {
        String msg="该"+SERVER_NAME+"服务暂时不可用!";
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return status;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return status.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return status.getReasonPhrase();
            }

            @Override
            public void close() {
            }

            @Override
            public InputStream getBody() throws IOException {
                return new ByteArrayInputStream(msg.getBytes());
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders headers = new HttpHeaders();
                headers.setContentType(MediaType.APPLICATION_JSON);
                return headers;
            }
        };
    }

    @Bean
    public MyFallback eurekaClientFallback() {
        return new MyFallback();
    }   
}