Spring Cloud Gateway快速体验

使用Spring Cloud Gateway作为API网关的一种实现，可以完成统一的权限校验、耗时统计、限流、计费等功能。类似功能产品有Zuul（Nginx也有点类似）

快速体验

添加依赖

pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
    <version>2.1.1.RELEASE</version>
</dependency>

配置跳转

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

    @Bean
    public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
                //所有url都跳转到www.baidu.com
                .route(r -> r.path("/**")
                        .uri("https://www.baidu.com")
                )
                .build();
    }
}

访问体验

浏览器访问http://localhost:8080会显示百度首页内容

GlobalFilter

GlobalFilter只要注册到Spring容器，就可以应用在所有请求，比如监控请求耗时

定义全局Filter

ElapsedFilter.java

import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

@Slf4j
@Component
public class ElapsedFilter implements GlobalFilter, Ordered {
    private static final String ELAPSED_TIME_BEGIN = "elapsedTimeBegin";

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        exchange.getAttributes().put(ELAPSED_TIME_BEGIN, System.currentTimeMillis());
        return chain.filter(exchange).then(
                Mono.fromRunnable(() -> {
                    Long startTime = exchange.getAttribute(ELAPSED_TIME_BEGIN);
                    if (startTime != null) {
                        log.info(exchange.getRequest().getURI().getRawPath() + ": cost " + (System.currentTimeMillis() - startTime) + "ms");
                    }
                })
        );
    }

    @Override
    public int getOrder() {
        return Ordered.HIGHEST_PRECEDENCE;
    }
}

访问http://localhost:8080/index.html可以在日志中看到所有请求的耗时情况
ps: ElapsedFilter实现了GlobalFilter接口

GatewayFilter

有的Filter并不希望应用在所有的URL上，比如权限校验，有的URL需要用户登录之后，有的不需要登录。这个时候就要会用GatewayFilter，可以配置到不同route规则上

定义网关接口

AuthFilter.java

import com.google.gson.JsonObject;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.core.Ordered;
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.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.nio.charset.StandardCharsets;


@Component
public class AuthFilter implements GatewayFilter, Ordered {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        String token = exchange.getRequest().getQueryParams().getFirst("authToken");
        //返回401状态码和提示信息
        if (StringUtils.isEmpty(token)) {
            ServerHttpResponse response = exchange.getResponse();
            JsonObject message = new JsonObject();
            message.addProperty("status", -1);
            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", "text/plain;charset=UTF-8");
            return response.writeWith(Mono.just(buffer));
        }
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return -100;
    }
}

GatewayApplication.java

@SpringBootApplication
public class GatewayApplication {

    @Resource
    private AuthFilter authFilter;

    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }

    @Bean
    public RouteLocator customRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
                .route(r -> r.path("/**")
                        .filters(f -> f.filter(authFilter)
                                .addRequestParameter("name", "tenmao")
                        )
                        .uri("https://www.qq.com")
                )
                .build();
    }
}

参考

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