1103springcloud复习，eureka注册中心的使用

1. 

2. "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>4.0.0modelVersion>
    
       <groupId>cloud1103groupId>
       <artifactId>cloud1103artifactId>
       <packaging>pompackaging>
       <version>1.0-SNAPSHOTversion>
       <modules>
           <module>order-servicemodule>
           <module>user-servicemodule>
       modules>
    
       
       <parent>
           <groupId>org.springframework.bootgroupId>
           <artifactId>spring-boot-starter-parentartifactId>
           <version>2.3.9.RELEASEversion>
       parent>
       
       <properties>
           <maven.compiler.source>8maven.compiler.source>
           <maven.compiler.target>8maven.compiler.target>
           <java.version>1.8java.version>
           <spring-cloud.version>Hoxton.SR10spring-cloud.version>
           <mysql.version>5.1.47mysql.version>
           <mybatis.version>2.1.1mybatis.version>
       properties>
    
    
       
       <dependencyManagement>
           <dependencies>
               
               <dependency>
                   <groupId>org.springframework.cloudgroupId>
                   <artifactId>spring-cloud-dependencesartifactId>
                   <version>${spring-cloud.version}version>
                   <type>pomtype>
                   <scope>importscope>
               dependency>
               
               <dependency>
                   <groupId>mysqlgroupId>
                   <artifactId>mysql-connector-javaartifactId>
                   <version>${mysql.version}version>
               dependency>
               
               <dependency>
                   <groupId>org.mybatis.spring.bootgroupId>
                   <artifactId>mybatis-spring-boot-starterartifactId>
                   <version>${mybatis.version}version>
               dependency>
           dependencies>
       dependencyManagement>
    
    
   project>
   

1. "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>cloud1103artifactId>
           <groupId>cloud1103groupId>
           <version>1.0-SNAPSHOTversion>
       parent>
       <modelVersion>4.0.0modelVersion>
    
       <artifactId>user-serviceartifactId>
    
       <properties>
           <maven.compiler.source>8maven.compiler.source>
           <maven.compiler.target>8maven.compiler.target>
       properties>
    
       <dependencies>
           <dependency>
               <groupId>org.springframework.bootgroupId>
               <artifactId>spring-boot-starter-webartifactId>
           dependency>
           
           <dependency>
               <groupId>mysqlgroupId>
               <artifactId>mysql-connector-javaartifactId>
           dependency>
           <dependency>
               <groupId>org.mybatis.spring.bootgroupId>
               <artifactId>mybatis-spring-boot-starterartifactId>
           dependency>
       dependencies>
    
       <build>
           <plugins>
               <plugin>
                   <groupId>org.springframework.bootgroupId>
                   <artifactId>spring-boot-maven-pluginartifactId>
               plugin>
           plugins>
       build>
    
   project>
   

user-service模块新建启动类，建立三层架构，postman测试

同样的方式来配置和测试order-service模块

使用注册中心eureka来完成远程服务调用

1. pom文件

2.  
       <dependencies>
           <dependency>
               <groupId>org.springframework.cloudgroupId>
               <artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
               <version>2.2.7.RELEASEversion>
           dependency>
       dependencies>
   

3. 配置：
4. 
5. 启动类
6. 
7. 启动成功：访问成功
8. 

1. user的pom文件
2. 
3. user的配置文件

4. # 将user服务加进注册中心
   eureka:
     client:
       service-url:
         defaultZone: http://127.0.0.1:10086/eureka
   

5. 启动加入成功：
6. 

1. 先调出dushboard出来
2. 
3. 
4. 
5. 
6. 按下图要求，仿照复制一个user服务的实例，注意端口
7. 
8. 

1. 首先要在订单服务启动类加入负载均衡注解：  @LoadBalanced
2. 
3. 然后修改订单业务层的代码
4. 

5. @Service
   public class OrderServiceImpl implements OrderService {
       @Autowired
       private OrderMapper orderMapper;
    
       @Autowired
       private RestTemplate restTemplate;
    
       public Order queryOrder(Long id){
           Order order = orderMapper.selectOne(id);
   //        User user = restTemplate.getForObject("http://localhost:8081/user/1", User.class);
           User user = restTemplate.getForObject("http://userservice/user/" + order.getUserId(), User.class);
           order.setUser(user);
           return order;
       }
   }
   

1. 我们通过post调用订单服务，观察两个user服务的实例，经过了负载均衡之后，是通过哪个实例去调用服务
2. 通过dushboard控制台打印的信息，可以发现是负载均衡的默认机制（轮循），每个实例一个一次的来
3. 

1. 选择哪种均衡策略：在Irule这个类当中
2. ribbon负载均衡规则：
   1. IRule接口
   2. 默认的规则：ZoneAvoidanceRule  用的轮循
3. ribbon使用的拦截器：LoadBalancerInterceptor