Use of Eureka and Ribbon in SpringCloud

What is Eureka and Ribbon

Cluster setup

• Single machine simulation cluster

Steps to train of thought

1. Create parent project import dependencies
2. Create three databases with the same structure
3. Create an Entity Class (POJO) Project (API)
4. Create three service providers for the same business processing
5. Create a service consumer
6. Create three registries
7. Created as maven project
8. Modifying the hosts file

Create SpringCloud query points

• Why not just create a SpringBoot project?

A: There is a Maven dependency called Spring-Cloud-Dependencies that versions the components that Spring Cloud needs. Because of the strict version mapping of Spring Cloud components, an error can be reported if one is not noticed. It would be very troublesome if all the dependencies of the corresponding version were manually derived.

• In order tospring cloud-Hoxton.SR10thespring-cloud-dependenciesFor example, versions of common components have been specified,

• Why does the parent POM use dependencyManagement?

A: In the POM file at the top level of our project, we will see the dependencyManagement element. The version of the JAR package is managed through its element, allowing a dependency to be referenced in a subproject without having to list the version number displayed. Maven moves up the parent-child hierarchy until it finds a project that has a dependencyManagement element, and then it uses the version number specified in that dependencyManagement element.

• DependencyManagement: Dependencies?

Create parent project import dependencies

      
<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>org.example</groupId>
    <artifactId>SpringCloud-Project</artifactId>
    <version>1.0 the SNAPSHOT</version>
    <properties>
        <junit.version>4.13.2</junit.version>
        <lombok.version>1.18.18</lombok.version>
        <log4j.version>1.2.17</log4j.version>
        <logback.version>1.2.3</logback.version>
        <mybatis-starter.version>2.1.4</mybatis-starter.version>
        <mysql.version>8.0.22</mysql.version>

        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <packaging>pom</packaging>
<! -- Project dependencies must be consistent -->
<dependencyManagement>
    <dependencies>
       <! -- Cloud dependency -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Hoxton.SR10</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
       <! -- Boot dependency is compatible with cloud version -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>2.3.9. RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <! -- druid data source -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.5</version>
        </dependency>
        <dependency>
       <! -- boot boot -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <version>2.3.9. RELEASE</version>
        </dependency>
         <! -- Logs are related to laziness -->
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>${logback.version}</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>${lombok.version}</version>
        </dependency>
<! -- mybaties -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>${mybatis-starter.version}</version>
        </dependency>
<! -- Web dependency -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>2.3.9. RELEASE</version>

        </dependency>
    </dependencies>
</dependencyManagement>
</project>
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Three databases

Entity class

@Data
@NoArgsConstructor
@Accessors(chain = true)/ / chain
public class Dept implements Serializable {// Serialize
    private Integer deptId;
    private String dname;
    private String db_source;

    public Dept(String dname) {
        this.dname = dname; }}Copy the code

Creating a service provider

• Import maven dependencies, and import your own entity class dependencies

      
<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-Project</artifactId>
        <groupId>org.example</groupId>
        <version>1.0 the SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringCloud-Provider-8001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
      <! -- Write your own entity class -->
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>SpringCloud-Api</artifactId>
            <version>1.0 the SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>
        <! --test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <! --jetty-->
<! -- <dependency>-->
<! -- <groupId>org.springframework.boot</groupId>-->
<! -- <artifactId>spring-boot-starter-jetty</artifactId>-->
<! -- </dependency>-->
        <! -- Hot Deployment Tool -->
<! -- <dependency>-->
<! -- <groupId>org.springframework.boot</groupId>-->
<! -- <artifactId>spring-boot-devtools</artifactId>-->
<! - < version > 2.3.9. RELEASE < / version > -- >
<! -- </dependency>-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <! -- Config service info -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

</project>
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• Creating an interface Mapper interface

@Mapper
@Repository// Spring DAO layer markup
public interface DeptDao {
    boolean addDept(Dept dept);
    Dept getById(int id);
    List<Dept> getAll(a);
}
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• Create a Service layer interface

public interface DeptService {
    boolean addDept(Dept dept);
    Dept getById(int id);
    List<Dept> getAll(a);
}
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• Implementing the Service Interface

@Service
public class DeptServiceImpl implements DeptService {
    @Autowired
    DeptDao deptDao;
    @Override
    public boolean addDept(Dept dept) {
        return deptDao.addDept(dept);
    }

    @Override
    public Dept getById(int id) {
        return deptDao.getById(id);
    }

    @Override
    public List<Dept> getAll(a) {
        returndeptDao.getAll(); }}Copy the code

• Mybatis -config Enables level 2 cache

      
<! DOCTYPEconfiguration
        PUBLIC "- / / mybatis.org//DTD Config / 3.0 / EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>
     <settings>
         <setting name="cacheEnabled" value="ture"/>
     </settings>
</configuration>
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• Configuration DeptMapper. XML

      
<! DOCTYPEmapper
        PUBLIC "- / / mybatis.org//DTD Mapper / 3.0 / EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.cloud.dao.DeptDao">

    <insert id="addDept">
        insert into springcloud.dept (dname, db_source) values (#{dname},DATABASE())
    </insert>
    <select id="getById" resultType="com.cloud.pojo.Dept" parameterType="int">
        select * from springcloud.dept where deptId=#{deptID}
    </select>
    <select id="getAll" resultType="com.cloud.pojo.Dept">
        select * from springcloud.dept
    </select>
</mapper>
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• Configure application.yaml to use the Druid data source

server:
  port: 8001

mybatis:
  type-aliases-package: com.cloud.pojo
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml
spring:
  application:
    name: springcloud-provider-dept
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/springcloud? useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=Asia/Shanghai
    driver-class-name: com.mysql.cj.jdbc.Driver
    # c
    #SpringBoot does not inject these by default, you need to bind them yourself
    #druid Data source proprietary configuration
    type: com.alibaba.druid.pool.DruidDataSource
    initialSize: 5
    minIdle: 5
    maxActive: 20
    maxWait: 60000
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: SELECT 1 FROM DUAL
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    poolPreparedStatements: true

    # Configure filters to monitor statistics interception, stat: monitor statistics, log4j: logging, wall: defend against SQL injection
    # if an error is allowed, Java. Lang. ClassNotFoundException: org.. Apache Log4j. Properity
    Import log4j dependencies
    filters: stat,wall,log4j
    maxPoolPreparedStatementPerConnectionSize: 20
    useGlobalDataSourceStat: true
    connectionProperties: druid.stat.mergeSql=true; druid.stat.slowSqlMillis=500
Where is the Eureka service registered
eureka:
  client:
    service-url: # registered address ~
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/
  instance:
    instance-id: springcloud-provider-dept-8001

Configure the service information to specify what the service does
info:
  app.name: The name of it
  company.name: XXX company
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• Druid description of parameter configuration
• Create a Controller

// Provides restful services
@RestController
public class DeptController {
    @Autowired
    private DeptService service;
    @RequestMapping(value = "/add")// Use port 8001 instead of post. The consumer server is OK
    public boolean add(@RequestBody Dept dept){
        System.out.println(dept.getDname());
        return service.addDept(dept);
    }
    @GetMapping("/byId/{id}")
    public Dept getDeptById(@PathVariable int id){
        return service.getById(id);
    }
    @GetMapping("/getAll")
    public List<Dept> getAll(a){
        returnservice.getAll(); }}Copy the code

• Creating a startup class

@EnableEurekaClient// Let Eureka find it
@SpringBootApplication
public class DeptProvider_8001{
    public static void main(String[] args) { SpringApplication.run(DeptProvider_8001.class,args); }}Copy the code

• Change the port number in the configuration file, change the database name, and change the name of the startup class to the corresponding port number

Creating a registry

• Import dependence

      
<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-Project</artifactId>
        <groupId>org.example</groupId>
        <version>1.0 the SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringCloud-Eurika-7001</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>

</project>
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• Create the launcher

@SpringBootApplication
@EnableEurekaServer// Activate Eureka Server configuration comments
public class Eureka_7001 {
    public static void main(String[] args) { SpringApplication.run(Eureka_7001.class,args); }}Copy the code

• application.yaml

#server:
# port: 7001
# # Eureka configuration
#eureka:
# instance:
Eureka server instance name
# client:
# register-with-eureka: false # Indicates whether to register yourself with the Eureka registry
# fetch-registry: false # fetch-registry: false # fetch-registry: false
# service-url: # monitor page ~
# defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
spring:
  application:
    name: eureka-server-7001

server:
  port: 7001

eureka:
  instance:
    hostname: eureka7001.com
  client:
    # Whether it should register its information with the Eureka server for others to find. Set to false because it is the Eureka server
    register-with-eureka: false
    Whether eureka registry information should be obtained from the Eureka server. Set to false because it is the Eureka server
    fetch-registry: false
    service-url: # registered address ~
      defaultZone: http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/
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• The other two are the same, just change the port number

Creating service consumers

• Import dependence

      
<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-Project</artifactId>
        <groupId>org.example</groupId>
        <version>1.0 the SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>SpringCloud-Consumer-dept-80</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
     <dependencies>
         <! -- Entity class -->
         <dependency>
             <groupId>org.example</groupId>
             <artifactId>SpringCloud-Api</artifactId>
             <version>1.0 the SNAPSHOT</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
         </dependency>
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
         </dependency>


     </dependencies>
</project>
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• Write the Configuration class

@Configuration
public class ConfigBeans {
    //IRule, the interface that defines the "rule" of LoadBalancer. You can think of rules as load balancing policies. Well-known load balancing strategies include polling, response time based, etc
    // The default is polling
    @Bean
    @LoadBalanced// Configure load balancing to implement RestTemplate
    public RestTemplate restTemplate(a){
        return newRestTemplate(); }}Copy the code

• Configuration class for load balancing (custom policy, or built-in policy (polling, random, weight…) ,), do not be in the same directory as the startup class, because in the same context, all service consumption will use the same load balancing policy.

@Configuration
public class MyRuleConfiguration {
    @Bean
    public IRule myRule(a){
        return newRandomRule(); }}Copy the code

• Controller

@RestController
public class DeptConsumerController {
    // Consumer, there should be no service layer
    //RestTemplate is a simple restful service template that provides multiple convenient methods for accessing remote HTTP services
    @Autowired
    private RestTemplate restTemplate;
    //private static final String REST_URL_PREFIX="http://localhost:8001";
    private static final String REST_URL_PREFIX="http://SPRINGCLOUD-PROVIDER-DEPT";// Access by service name
    @GetMapping("/consumer/add/")
    public boolean add(Dept dept){
        System.out.println(dept.getDname());
        return restTemplate.postForObject(REST_URL_PREFIX+"/add",dept,Boolean.class);
    }
    @GetMapping("/consumer/byId/{id}")
    public Dept getDeptById(@PathVariable int id){
        return restTemplate.getForObject(REST_URL_PREFIX+"/byId/"+id,Dept.class);
    }
    @GetMapping("/consumer/getAll")
    public List getAll(a){
        return restTemplate.getForObject(REST_URL_PREFIX+"/getAll",List.class); }}Copy the code

• application.yaml

server:
  port: 80

# eureka configuration
eureka:
  client:
    register-with-eureka: false # Do not register yourself with Eureka
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7003.com:7003/eureka/,http://eureka7002.com:7002/eureka/
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• Start the class

@SpringBootApplication
                      //(" Service name ", "Custom Load Balancing Policy Configuration class.class")
@RibbonClient(name="SPRINGCLOUD-PROVIDER-DEPT",configuration= MyRuleConfiguration.class)
public class DeptConsumer_80 {
    public static void main(String[] args) { SpringApplication.run(DeptConsumer_80.class,args); }}Copy the code

Modify the hosts file on the computer

• Three domain names represent. Three servers. Simulate it

127.0.0.1 eureka7001.com
127.0.0.1 eureka7002.com
127.0.0.1 eureka7003.com
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summary

The project structure

The dependence is going to be derivative of theta

The configuration file

• Key configurations for service providers

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

• Key configuration of the registry

• Key configurations for service consumers

Key annotations and objects

consumers

• • @LoadBalanced.Load balancing the request template
• • @RibbonClient.Use the Ribbon for load balancing
• • RestTemplateIn the Controller, make a request to the service provider
• • IRule.Load balancing policy interface
• • RestTemplate

= = = = = = = = = = = = = = = = = = = = = = = = = = = =

The registry

• • @EnableEurekaServer.Enable comments for Eureka Server-related configurationsOn the startup class

Service provider

• • @EnableEurekaClient.Enable the Eureka discovery configurationOn the startup class

The final result