springcloud之Zuul初识篇—过滤器细节

女爷i 2023-07-25 12:32 99阅读 0赞

1、过滤器校验禁止向业务服务请求

@Override
        public Object run() throws ZuulException {
            RequestContext requestContext = RequestContext.getCurrentContext();
            Boolean flag = true;
            //设置不在向下执行请求
            requestContext.setSendZuulResponse(false);
            requestContext.setResponseStatusCode(HttpStatus.TOO_MANY_REQUESTS.value());
            //返回给客户端的信息
            requestContext.setResponseBody("未获取到令牌请重试！");
            return null;
        }

**PS**: 在pre类型或route中**filterOrder**的**<=9**时，设置requestContext.**setSendZuulResponse(false)**;网关不会调用业务服务。

2、某过滤器设置**setSendZuulResponse(false)**后，后续自定义过滤器不在执行业务逻辑。

//第一个过滤器 
    public Object run() throws ZuulException {
            RequestContext requestContext = RequestContext.getCurrentContext();
            Boolean flag = true;
            //设置标记，告诉下一个过滤器是否要执行业务逻辑
            requestContext.set("f",flag);
            requestContext.setSendZuulResponse(false);
            requestContext.setResponseStatusCode(HttpStatus.TOO_MANY_REQUESTS.value());
            requestContext.setResponseBody("未获取到令牌请重试！");
            return null;
        }
    -----------------------------------------------
    //第二个过滤器
        @Override
        public boolean shouldFilter() {
            RequestContext requestContext = getCurrentContext();
            //获取上一个过滤器赋值的标记，判断是否需要执行当前过滤器的业务逻辑
            boolean flag = (Boolean) requestContext.get("f");
            if(!flag){
                return flag;
            }
            return flag;
        }

**PS**：通过业务代码中设计标记动态控制过滤器是否执行

3、请求业务服务时添加参数

@Override
        public Object run() throws ZuulException {
            try {
                RequestContext requestContext = RequestContext.getCurrentContext();
                InputStream in = (InputStream) requestContext.get("requestEntity");
                if(null==in){
                    in =requestContext.getRequest().getInputStream();
                }
                //原有信息从流中拿出来转化成字符串
                String body = StreamUtils.copyToString(in,Charset.forName("utf-8"));
                //这里转化成json，在json中添加信息（如：用户名称、id等）
                JSONObject jsonObject =  JSONObject.parseObject(body);
                jsonObject.put("uesrName","Niki");
                body = jsonObject.toJSONString();
                //将调整后的信息转成流赋给request
                byte[] bytes = body.getBytes("utf-8");
                requestContext.setRequest(new HttpServletRequestWrapper(RequestContext.getCurrentContext().getRequest()) {
                    @Override
                    public ServletInputStream getInputStream() throws IOException {
                        return new ServletInputStreamWrapper(bytes);
                    }
    
                    @Override
                    public int getContentLength() {
                        return bytes.length;
                    }
    
                    @Override
                    public long getContentLengthLong() {
                        return bytes.length;
                    }
                });
            }catch (Exception e){
                e.printStackTrace();
            }
    
            return null;
        }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RlbmdkYWkxMjM2NTQ_size_16_color_FFFFFF_t_70][]

4、返回客户端时添加参数(如：一次性的token令牌)

import com.netflix.zuul.ZuulFilter;
    import com.netflix.zuul.context.RequestContext;
    import com.netflix.zuul.exception.ZuulException;
    import org.springframework.cloud.netflix.zuul.filters.support.FilterConstants;
    import org.springframework.stereotype.Component;
    import org.springframework.util.StreamUtils;
    
    import javax.servlet.http.HttpServletResponse;
    import java.io.ByteArrayInputStream;
    import java.nio.charset.Charset;
    import java.util.UUID;
    
    
    @Component
    public class PostFristFilter extends ZuulFilter {
        @Override
        public String filterType() {
            return FilterConstants.POST_TYPE;
        }
    
        @Override
        public int filterOrder() {
            return FilterConstants.SEND_RESPONSE_FILTER_ORDER - 2;
        }
    
        @Override
        public boolean shouldFilter() {
            return true;
        }
    
        @Override
        public Object run() throws ZuulException {
            RequestContext requestContext = RequestContext.getCurrentContext();
            try {
                HttpServletResponse servletResponse = requestContext.getResponse();
                //给返回的请求头添加信息
                servletResponse.addHeader("X-Foo",UUID.randomUUID().toString());
                String body =  StreamUtils.copyToString(requestContext.getResponseDataStream(),Charset.forName("utf-8"));
                /*JSONObject jsonObject =  JSONObject.parseObject(body);
                jsonObject.put("token","12345");*/
                body= body+"  添加postFilter信息";
                //两种方式都可以返回
                //requestContext.setResponseBody(body);
                requestContext.setResponseDataStream(new ByteArrayInputStream(body.getBytes("UTF-8")));
            }catch (Exception e){
                throw  new ZuulException(e.getMessage(),500,e.toString());
            }
    
            return null;
        }
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2RlbmdkYWkxMjM2NTQ_size_16_color_FFFFFF_t_70 1][]

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