项目笔记13：GateWay网关

电玩女神 2022-11-18 13:55 177阅读 0赞

## 1、什么是网关 ##

网关相当于服务器和客户端之间的一面墙，起到请求转发、负载均衡、权限控制等效果

跨域问题，之前在每个Controller中都需要加一个@CrossOrigin，都可以在网关中解决

## 2、Gateway网关 ##

Gateway是SpringCloud中的一个组件，需要将网关和服务都在注册中心中注册，通过服务进行访问

Spring Cloud Gateway中几个重要的概念：

1）路由：每个服务对应不同的地址

2）断言：是一种匹配规则，一匹配到就可以往下执行

3）过滤器：过滤器将会对请求和响应做修改处理

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负载均衡方式：

1）轮训

2）权重

3）最少请求时间：谁的请求时间最短就去访问谁

## 3、Gateway网关服务配置 ##

## **1）在infrastructure模块下创建api\_gateway模块** ##

2）在pom.xml引入依赖

<dependencies>
            <dependency>
                <groupId>com.atguigu</groupId>
                <artifactId>common_utils</artifactId>
                <version>0.0.1-SNAPSHOT</version>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-gateway</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>com.google.code.gson</groupId>
                <artifactId>gson</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>
        </dependencies>

3）**编写application.properties配置文件**

# 服务端口
    server.port=8222
    # 服务名
    spring.application.name=service-gateway
    # nacos服务地址
    spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848
    
    # 使用服务发现路由
    spring.cloud.gateway.discovery.locator.enabled=true
    
    # 设置路由id
    spring.cloud.gateway.routes[0].id=service-acl
    #设置路由的uri lb://nacos上的服务名
    spring.cloud.gateway.routes[0].uri=lb://service-acl
    #设置路由断言,代理servicerId为auth-service的/auth/路径
    spring.cloud.gateway.routes[0].predicates= Path=/*/acl/**
    
    #配置service-edu服务
    spring.cloud.gateway.routes[1].id=service-edu
    spring.cloud.gateway.routes[1].uri=lb://service-edu
    spring.cloud.gateway.routes[1].predicates= Path=/eduservice/**
    
    #配置service-ucenter服务
    spring.cloud.gateway.routes[2].id=service-msm
    spring.cloud.gateway.routes[2].uri=lb://service-msm
    spring.cloud.gateway.routes[2].predicates= Path=/edumsm/**

4)**编写启动类**

@SpringBootApplication
    @EnableDiscoveryClient
    public class ApiGatewayApplication {
        public static void main(String[] args) {
            SpringApplication.run(ApiGatewayApplication.class, args);
        }
    }

## 4、通过解决网关解决跨域问题 ##

不需要每次在Controller中添加@CrossOrigin注解来解决跨域问题

**创建配置类CorsConfig**

@Configuration
    public class CorsConfig {
        @Bean
        public CorsWebFilter corsFilter() {
            CorsConfiguration config = new CorsConfiguration();
            config.addAllowedMethod("*");
            config.addAllowedOrigin("*");
            config.addAllowedHeader("*");
    
            UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource(new PathPatternParser());
            source.registerCorsConfiguration("/**", config);
    
            return new CorsWebFilter(source);
        }
    }

5、**全局Filter，统一处理会员登录与外部不允许访问的服务**

创建filter：AuthGlobalFilter

@Component
    public class AuthGlobalFilter implements GlobalFilter, Ordered {
    
        private AntPathMatcher antPathMatcher = new AntPathMatcher();
    
        @Override
        public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
            ServerHttpRequest request = exchange.getRequest();
            String path = request.getURI().getPath();
            //谷粒学院api接口，校验用户必须登录
            if(antPathMatcher.match("/api/**/auth/**", path)) {
                List<String> tokenList = request.getHeaders().get("token");
                if(null == tokenList) {
                    ServerHttpResponse response = exchange.getResponse();
                    return out(response);
                } else {
    //                Boolean isCheck = JwtUtils.checkToken(tokenList.get(0));
    //                if(!isCheck) {
                        ServerHttpResponse response = exchange.getResponse();
                        return out(response);
    //                }
                }
            }
            //内部服务接口，不允许外部访问
            if(antPathMatcher.match("/**/inner/**", path)) {
                ServerHttpResponse response = exchange.getResponse();
                return out(response);
            }
            return chain.filter(exchange);
        }
    
        @Override
        public int getOrder() {
            return 0;
        }
    
        private Mono<Void> out(ServerHttpResponse response) {
            JsonObject message = new JsonObject();
            message.addProperty("success", false);
            message.addProperty("code", 28004);
            message.addProperty("data", "鉴权失败");
            byte[] bits = message.toString().getBytes(StandardCharsets.UTF_8);
            DataBuffer buffer = response.bufferFactory().wrap(bits);
            //response.setStatusCode(HttpStatus.UNAUTHORIZED);
            //指定编码，否则在浏览器中会中文乱码
            response.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
            return response.writeWith(Mono.just(buffer));
        }
    }

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