Spring Cloud 实战 (三) 服务网关 gateway

蔚落 2022-02-02 23:37 323阅读 0赞

在[Spring Cloud (二) 服务的注册与发现][Spring Cloud _]的基础上 创建一个名为SpringCloud-gateway的项目  
在 Maven 中 添加依赖：

<dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-gateway</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-webflux</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>
    		
    		<dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Greenwich.RELEASE</version>
                    <type>pom</type>
                    <scope>import</scope>
                    <exclusions>
                    </exclusions>
                </dependency>
            </dependencies>
        </dependencyManagement>

然后修改配置文件：

server:
      port: 8080
      
    spring:
      application:
        name: gateway
      cloud:
        gateway:
          discovery:
            locator:
              enabled: true #表示是否与服务发现组件（register）进行结合，通过serviceId（必须设置成大写）转发到具体的服务实例 默认：false
              
    logging:
      level:
        org.springframework.cloud.gateway: trace
        org.springframework.http.server.reactive: debug
        org.springframework.web.reactive: debug
        reactor.ipc.netty: debug
        
    eureka:
      client:
        serviceUrl:
          defaultZone: http://localhost:8761/eureka/

创建服务拦截：  
新建一个类ApiGlobalFilter并继承GlobalFilter：

import org.apache.commons.lang.StringUtils;
    import org.springframework.cloud.gateway.filter.GatewayFilterChain;
    import org.springframework.cloud.gateway.filter.GlobalFilter;
    import org.springframework.core.io.buffer.DataBuffer;
    import org.springframework.http.HttpStatus;
    import org.springframework.http.server.reactive.ServerHttpResponse;
    import org.springframework.stereotype.Component;
    import org.springframework.web.server.ServerWebExchange;
    import reactor.core.publisher.Mono;
    
    import java.nio.charset.StandardCharsets;
    import java.util.HashMap;
    import java.util.Map;
    
    @Component
    public class ApiGlobalFilter implements GlobalFilter {
    
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            String token = exchange.getRequest().getQueryParams().getFirst("token");
            if (StringUtils.isBlank(token)) {//验证token值
                ServerHttpResponse response = exchange.getResponse();
                Map<String,Object> message = new HashMap<>();
                message.put("code", 5001);
                message.put("message", "鉴权失败，无token值");
                byte[] bits = message.toString().getBytes(StandardCharsets.UTF_8);
                DataBuffer buffer = response.bufferFactory().wrap(bits);
                response.setStatusCode(HttpStatus.UNAUTHORIZED);
                response.getHeaders().add("Content-Type", "text/json;charset=UTF-8");
                return response.writeWith(Mono.just(buffer));
            }
            return chain.filter(exchange);
        }
    }

然后访问[http://localhost:8080/SPRINGCLOUD-CLIENT-A/hello/index][http_localhost_8080_SPRINGCLOUD-CLIENT-A_hello_index]  
效果图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjExODI4NA_size_16_color_FFFFFF_t_70]

添加错误拦截：(友好提示)  
新建一个类JsonExceptionHandler并且继承DefaultErrorWebExceptionHandler类：

import org.springframework.boot.autoconfigure.web.ErrorProperties;
    import org.springframework.boot.autoconfigure.web.ResourceProperties;
    import org.springframework.boot.autoconfigure.web.reactive.error.DefaultErrorWebExceptionHandler;
    import org.springframework.boot.web.reactive.error.ErrorAttributes;
    import org.springframework.context.ApplicationContext;
    import org.springframework.http.HttpStatus;
    import org.springframework.web.reactive.function.server.*;
    
    import java.util.HashMap;
    import java.util.Map;
    
    /** 
    * @author  作者 : 小布
    * @version 创建时间 : 2019年5月8日 上午10:22:23 
    * @explain 类说明 : 自定义异常处理 返回统一的 JSON 格式
    */
    public class JsonExceptionHandler extends DefaultErrorWebExceptionHandler {
    
        public JsonExceptionHandler(ErrorAttributes errorAttributes, ResourceProperties resourceProperties,
                                    ErrorProperties errorProperties, ApplicationContext applicationContext) {
            super(errorAttributes, resourceProperties, errorProperties, applicationContext);
        }
    
        /**
         * 获取异常属性
         */
        @Override
        protected Map<String, Object> getErrorAttributes(ServerRequest request, boolean includeStackTrace) {
            int code = 500;
            Throwable error = super.getError(request);
            if (error instanceof org.springframework.cloud.gateway.support.NotFoundException) {
                code = 404;
            }
            return response(code, this.buildMessage(request, error));
        }
    
        /**
         * 指定响应处理方法为 JSON 处理的方法
         * @param errorAttributes
         */
        @Override
        protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
            return RouterFunctions.route(RequestPredicates.all(), this::renderErrorResponse);
        }
    
        /**
         * 根据 code 获取对应的 HttpStatus
         * @param errorAttributes
         */
        @Override
        protected HttpStatus getHttpStatus(Map<String, Object> errorAttributes) {
            int statusCode = (int) errorAttributes.get("code");
            return HttpStatus.valueOf(statusCode);
        }
    
        /**
         * 构建异常信息
         * @param request
         * @param ex
         * @return
         */
        private String buildMessage(ServerRequest request, Throwable ex) {
            StringBuilder message = new StringBuilder("Failed to handle request [");
            message.append(request.methodName());
            message.append(" ");
            message.append(request.uri());
            message.append("]");
            if (ex != null) {
                message.append(": ");
                message.append(ex.getMessage());
            }
            return message.toString();
        }
    
        /**
         * 构建返回的 JSON 数据格式
         * @param status        状态码
         * @param errorMessage  异常信息
         * @return
         */
        public static Map<String, Object> response(int status, String errorMessage) {
            Map<String, Object> map = new HashMap<>();
            map.put("code", status);
            map.put("message", errorMessage);
            return map;
        }
    
    }

需要添加以下配置类：

import org.springframework.beans.factory.ObjectProvider;
    import org.springframework.boot.SpringBootConfiguration;
    import org.springframework.boot.autoconfigure.web.ResourceProperties;
    import org.springframework.boot.autoconfigure.web.ServerProperties;
    import org.springframework.boot.context.properties.EnableConfigurationProperties;
    import org.springframework.boot.web.reactive.error.ErrorAttributes;
    import org.springframework.boot.web.reactive.error.ErrorWebExceptionHandler;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.annotation.Bean;
    import org.springframework.core.Ordered;
    import org.springframework.core.annotation.Order;
    import org.springframework.http.codec.ServerCodecConfigurer;
    import org.springframework.web.reactive.result.view.ViewResolver;
    
    import com.springcloud.exception.JsonExceptionHandler;
    
    import java.util.Collections;
    import java.util.List;
    /** 
    * @author  作者 : 小布
    * @version 创建时间 : 2019年5月8日 上午10:24:00 
    * @explain 类说明 : JsonExceptionHandler加载到Spring容器中的配置类
    */
    @SpringBootConfiguration
    @EnableConfigurationProperties({ServerProperties.class, ResourceProperties.class})
    public class ErrorHandlerConfiguration {
    
        private final ServerProperties serverProperties;
    
        private final ApplicationContext applicationContext;
    
        private final ResourceProperties resourceProperties;
    
        private final List<ViewResolver> viewResolvers;
    
        private final ServerCodecConfigurer serverCodecConfigurer;
    
        public ErrorHandlerConfiguration(ServerProperties serverProperties,
                                         ResourceProperties resourceProperties,
                                         ObjectProvider<List<ViewResolver>> viewResolversProvider,
                                         ServerCodecConfigurer serverCodecConfigurer,
                                         ApplicationContext applicationContext) {
            this.serverProperties = serverProperties;
            this.applicationContext = applicationContext;
            this.resourceProperties = resourceProperties;
            this.viewResolvers = viewResolversProvider.getIfAvailable(Collections::emptyList);
            this.serverCodecConfigurer = serverCodecConfigurer;
        }
    
        /**
         * gateway 启动时执行此方法，将 JsonExceptionHandler 注入到 Spring 容器中
         * 以便发生异常时执行自定义的 JsonExceptionHandler
         * @param errorAttributes
         * @return
         */
        @Bean
        @Order(Ordered.HIGHEST_PRECEDENCE)
        public ErrorWebExceptionHandler errorWebExceptionHandler(ErrorAttributes errorAttributes) {
            JsonExceptionHandler exceptionHandler = new JsonExceptionHandler(
                    errorAttributes,
                    this.resourceProperties,
                    this.serverProperties.getError(),
                    this.applicationContext);
            exceptionHandler.setViewResolvers(this.viewResolvers);
            exceptionHandler.setMessageWriters(this.serverCodecConfigurer.getWriters());
            exceptionHandler.setMessageReaders(this.serverCodecConfigurer.getReaders());
            return exceptionHandler;
        }
    }

效果图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjExODI4NA_size_16_color_FFFFFF_t_70 1]

[上一篇 Spring Cloud 实战 (二) 服务的注册与发现][Spring Cloud _]

[下一篇 Spring Cloud 实战 (四) 服务消费者 feign ][Spring Cloud _ _ _ feign]

[git源码地址][git]

[Spring Cloud _]: https://blog.csdn.net/weixin_42118284/article/details/89949330
[http_localhost_8080_SPRINGCLOUD-CLIENT-A_hello_index]: http://localhost:8080/SPRINGCLOUD-CLIENT-A/hello/index
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjExODI4NA_size_16_color_FFFFFF_t_70]: /images/20220203/380ffd74d37e44c9ac030319f6b925e3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjExODI4NA_size_16_color_FFFFFF_t_70 1]: /images/20220203/29aafb2be3f34ec38ad9cf0ef75234d1.png
[Spring Cloud _ _ _ feign]: https://blog.csdn.net/weixin_42118284/article/details/89949917
[git]: https://github.com/mars0520/Spring-Cloud