目录

一、gateway和nginx的区别？

二、Gateway流程

三、负载均衡 （gateway已经实现了）

四、gateway的application配置

五、gate的way的拓展

（1）gateway实现跨域

 （2）过滤器，用于同一处理

（3）覆盖默认的异常处理 和 自定义异常处理

---

一、gateway和nginx的区别？

注意： 使用nginx需要在接口上添加跨域注解@CrossOrigin，但是使用gateway，就不用了，它可以实现跨域。

二、Gateway流程

三、负载均衡 （gateway已经实现了）

四、gateway的application配置

# 服务端口
server.port=8222
# 服务名
spring.application.name=service-gateway

# 第一步: nacos服务地址
spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848

# 第二步：开启服务发现路由
spring.cloud.gateway.discovery.locator.enabled=true

# 第三步： 设置路由（可以有多个）
#设置路由id                         # 路由的id，可以随便写，但是建议写服务的名称
spring.cloud.gateway.routes[0].id=service-edu
#设置路由的uri                       # 在nacos中注册的服务名字
spring.cloud.gateway.routes[0].uri=lb://service-edu
#设置路由断言,代理servicerId为auth-service的/auth/路径
spring.cloud.gateway.routes[0].predicates= Path=/eduservice/**

。。。。。。

 五、gate的way的拓展

（1）gateway实现跨域

@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);
    }
}

 （2）过滤器，用于同一处理

@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));
    }
}

（3）覆盖默认的异常处理 和 自定义异常处理

@Configuration
@EnableConfigurationProperties({ServerProperties.class, ResourceProperties.class})
public class ErrorHandlerConfig {

    private final ServerProperties serverProperties;

    private final ApplicationContext applicationContext;

    private final ResourceProperties resourceProperties;

    private final List<ViewResolver> viewResolvers;

    private final ServerCodecConfigurer serverCodecConfigurer;

    public ErrorHandlerConfig(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;
    }

    @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;
    }
}

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) {
        Map<String, Object> map = new HashMap<>();
        map.put("success", false);
        map.put("code", 20005);
        map.put("message", "网关失败");
        map.put("data", null);
        return map;
    }

    /**
     * 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 int getHttpStatus(Map<String, Object> errorAttributes) {
        return 200;
    }
}