Spring cloud gateway是spring官方基于Spring 5.0、Spring Boot2.0和Project Reactor等技术开发的网关，Spring CloudGateway旨在为微服务架构提供简单、有效和统一的API路由管理方式，Spring Cloud Gateway作为Spring Cloud生态系统中的网关，目标是替代Netflix Zuul，其不仅提供统一的路由方式，并且还基于Filer链的方式提供了网关基本的功能，例如：安全、监控/埋点、限流等。

步骤：

1. 创建父工程springcloud_gateway，并添加上相关的依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.sakura</groupId>
    <artifactId>springcloud_gateway</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>gateway</module>
        <module>service</module>
    </modules>
    <packaging>pom</packaging>
    <name>springcloud_gateway</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.2.1.RELEASE</version>
        <relativePath/>
    </parent>

    <dependencyManagement>
        <dependencies>
            <!--Spring Cloud-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>0.2.2.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

2. 在父工程下面创建一个service模块，并添加添加上相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud_gateway</artifactId>
        <groupId>com.sakura</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>service</artifactId>
    <packaging>pom</packaging>
    <modules>
        <module>service_one</module>
        <module>service_two</module>
    </modules>

    <dependencies>
        <!--服务注册-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--服务调用-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.1.0.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

    </dependencies>

</project>

3. 同时在service模块中添加service-one和service-two两个子模块，两个子模块的端口分别属于8001和8002，在该两个模块中添加相关配置
   1）分别在两个子模块中的resource目录中配置相关application.yml的信息

server:
  port: 8001

spring:
  application:
    name: service-one #服务名
  profiles:
    active: dev #环境设置
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848 #nacos服务注册

server:
  port: 8002

spring:
  application:
    name: service-two #服务名
  profiles:
    active: dev #环境设置
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848 #nacos服务注册

2）分别在两个子模块中创建controller类用于接下来的测试

@RestController
@RequestMapping("/one")
public class OneController {

    @GetMapping("getOne")
    public String getOne(){
        return "调用端口号为8001的Api接口";
    }
}

@RestController
@RequestMapping("/two")
public class TwoController {

    @GetMapping("getTwo")
    public String getTwo(){
        return "调用端口号为8002的Api接口";
    }

}

3）在启动类上添加上@EnableDiscoveryClient注解，用于服务的注册与发现

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

}

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

}

4. 在父工程下再创建gateway模块，用于配置GateWay的路由转发
   1）导入相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud_gateway</artifactId>
        <groupId>com.sakura</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>gateway</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <!--nacos:用于服务注册与发现-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>

</project>

2）在resource目录下创建application.yml中编写相关配置信息(这里配置的8222端口后，只需通过该端口就可以访问到8001端口和8002端口的Api接口服务了)

server:
  port: 8222 #服务端口

spring:
  application:
    name: springcloud-gateway
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848 #nacos服务地址
    gateway:
      discovery:
        locator:
          enabled: true #使用服务发现路由
      routes:
        - id: SERVICE-ONE #设置路由id(理论上是可以随便写的)
          uri: lb://service-one #设置路由的url lb://nacos服务注册名称
          predicates:
            - Path=/one/** #路径匹配规则
        - id: SERVICE-TWO
          uri: lb://service-two
          predicates:
            - Path=/two/** #路径匹配规则

3）在config包下创建CorsConfig.java，用于解决跨域问题

@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);
    }
}

4）在GateApplication中添加相关注解

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

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以上基本就完成了基本代码的编写
接着启动Nacos，然后开启gateway、service-one、service-two的服务

在Nacos控制台的服务列表中看到对应的服务名就表示nacos开启了服务发现与注册

然后在浏览器中访问http://localhost:8222/one/getOne、http://localhost:8222/two/getTwo发现可以访问成功就说明成功实现了路由转发

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具体代码已上传到码云：https://gitee.com/culture36/spring-cloud_-gate-way