Zuul of SpringCloud: Service Gateway

For the use of Zuul in Web projects, see "Using Zuul in Spring Boot" above. The following example is the use of Zuul in Spring Cloud.

Development tools: IntelliJ IDEA 2019.2.3

One, server side

1. Create a project

Create a new SpringBoot project in IDEA with the name "zuul-eureka-server", select the SpringBoot version 2.1.10, and select Spring Cloud Discovery -> Eureka Server in the Dependencies interface.
The complete content of pom.xml is as follows:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zuul-eureka-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul-eureka-server</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</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. Modify the configuration application.yml

Modify the port number to 8761; cancel the registration of your information to the Eureka server, and do not grab the registration information from the Eureka server.

server:
  port: 8761
eureka:
  client:
    register-with-eureka: false
    fetch-registry: false

3. Modify the startup code

Add annotation @EnableEurekaServer

package com.example.zuuleurekaserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class ZuulEurekaServerApplication {

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

}

2. Service provider

1. Create a project

Create a new SpringBoot project in IDEA, except that the name is "zuul-provider", the other steps are the same as the server-side creation above.

2. Modify the configuration application.yml

server:
  port: 8000
spring:
  application:
    name: zuul-provider
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3. Add an entity class User.java

package com.example.zuulprovider;

public class User {
    String name;
    Integer age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

4. Modify the startup code

package com.example.zuulprovider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@EnableEurekaClient
@RestController
public class ZuulProviderApplication {

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

    @RequestMapping(value="/user/{name}", produces = MediaType.APPLICATION_JSON_VALUE)
    public User user(@PathVariable String name) {
        User u = new User();
        u.setName(name);
        u.setAge(30);
        return u;
    }
}

Three, the service caller

1. Create a project

Create a new SpringBoot project in IDEA, the name is "zuul-invoker", SpringBoot version selection 2.1.10, in the selection of Dependencies (dependencies) interface, check Spring Cloud Discovery -> Eureka Server, Spring Cloud Routing -> OpenFeign.
The complete content of pom.xml is as follows:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zuul-invoker</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul-invoker</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</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. Modify the configuration application.yml

server:
  port: 9000
spring:
  application:
    name: zuul-invoker
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3. Add an entity class User.java

package com.example.zuulinvoker;

public class User {
    String name;
    Integer age;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

4. Add a client interface UserClient.java

package com.example.zuulinvoker;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

//声明调用的服务名称
@FeignClient("zuul-provider")
public interface UserClient {
    @RequestMapping(method = RequestMethod.GET, value = "/user/{name}")
    User getUser(@PathVariable("name") String name);
}

5. Modify the startup class code CloudInvokerApplication.java

Add annotations @EnableEurekaClient and @EnableFeignClients

package com.example.zuulinvoker;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
public class ZuulInvokerApplication {

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

}

6. Add the controller InvokerController.java

package com.example.zuulinvoker;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class InvokerController {
    @Autowired
    private UserClient userClient;

    @RequestMapping(value = "/invokeUser/{name}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public User invokeUser(@PathVariable String name){
        User user = userClient.getUser(name);
        return user;
    }
}

Fourth, the gateway Zuul

1.
Create a new SpringBoot project in IDEA. The name is "zuul-gateway", and the SpringBoot version is 2.1.10. In the Dependencies selection interface, check Spring Cloud Discovery -> Eureka Server, Spring Cloud Routing- > Zuul.
The complete content of pom.xml is as follows:

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.10.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>zuul-gateway</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>zuul-gateway</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR4</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</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. Modify the startup code

Add annotation @EnableZuulProxy

package com.example.zuulgateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@SpringBootApplication
@EnableZuulProxy
public class ZuulGatewayApplication {

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

}

3. Modify the configuration application.yml

Register the gateway project to the Eureka server;
declare that all /user/** requests will be forwarded to the service with Id zuul-invoker for processing.

server:
  port: 8080
spring:
  application:
    name: zuul-gateway
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
zuul:
  routes:
    user:
      path: /user/**
      serviceId: zuul-invoker

Five, test

1. Start the server.
Browser access http://localhost:8761/, normal
2. Start the service provider
Browser access http://localhost:8000/user/Xiaoming
page output: {"name":"Xiaoming","age":30 }
3. Start the service caller.
Browser visit http://localhost:9000/invokeUser/Xiaoming
page output: {"name":"Xiaoming","age":30}
4. Start the gateway
http://localhost:8080/user/invokeUser/Xiaoming
page Output: {"name":"小明","age":30}
It can be seen that it was successfully forwarded and processed.

Zuul of SpringCloud: Service Gateway

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