1、整体思路
1.1、服务注册中心Eureka（可以是一个集群，对外暴露自己的地址）
1.2、服务提供者：启动后向Eureka注册自己的信息（地址，提供什么服务）
1.3、客户端消费者：向Eureka订阅服务，Eureka会将服务的所有提供者地址列表发送给消费者，并且定期更新
2、代码实现
2.1 创建父工程cloud-demo,导入依赖
1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
5 <modelVersion>4.0.0</modelVersion>
6
7 <groupId>com.myx.demo</groupId>
8 <artifactId>cloud-demo</artifactId>
9 <version>1.0.0-SNAPSHOT</version>
10 <modules>
11 <module>user-service</module>
12 <module>user-consumer</module>
13 <module>eureka-server</module>
14 </modules>
15
16 <packaging>pom</packaging>
17
18 <parent>
19 <groupId>org.springframework.boot</groupId>
20 <artifactId>spring-boot-starter-parent</artifactId>
21 <version>2.0.4.RELEASE</version>
22 <relativePath/>
23 </parent>
24
25 <properties>
26 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
27 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
28 <java.version>1.8</java.version>
29 <spring-cloud.version>Finchley.SR1</spring-cloud.version>
30 <mybatis.starter.version>1.3.2</mybatis.starter.version>
31 <mapper.starter.version>2.0.2</mapper.starter.version>
32 <druid.starter.version>1.1.9</druid.starter.version>
33 <mysql.version>5.1.32</mysql.version>
34 <pageHelper.starter.version>1.2.3</pageHelper.starter.version>
35 <leyou.latest.version>1.0.0-SNAPSHOT</leyou.latest.version>
36 </properties>
37
38 <dependencyManagement>
39 <dependencies>
40 <!-- springCloud -->
41 <dependency>
42 <groupId>org.springframework.cloud</groupId>
43 <artifactId>spring-cloud-dependencies</artifactId>
44 <version>${spring-cloud.version}</version>
45 <type>pom</type>
46 <scope>import</scope>
47 </dependency>
48 <!-- mybatis启动器 -->
49 <dependency>
50 <groupId>org.mybatis.spring.boot</groupId>
51 <artifactId>mybatis-spring-boot-starter</artifactId>
52 <version>${mybatis.starter.version}</version>
53 </dependency>
54 <!-- 通用Mapper启动器 -->
55 <dependency>
56 <groupId>tk.mybatis</groupId>
57 <artifactId>mapper-spring-boot-starter</artifactId>
58 <version>${mapper.starter.version}</version>
59 </dependency>
60 <!-- 分页助手启动器 -->
61 <dependency>
62 <groupId>com.github.pagehelper</groupId>
63 <artifactId>pagehelper-spring-boot-starter</artifactId>
64 <version>${pageHelper.starter.version}</version>
65 </dependency>
66 <!-- mysql驱动 -->
67 <dependency>
68 <groupId>mysql</groupId>
69 <artifactId>mysql-connector-java</artifactId>
70 <version>${mysql.version}</version>
71 </dependency>
72 </dependencies>
73 </dependencyManagement>
74
75 <build>
76 <plugins>
77 <plugin>
78 <groupId>org.springframework.boot</groupId>
79 <artifactId>spring-boot-maven-plugin</artifactId>
80 </plugin>
81 </plugins>
82 </build>
83 </project>2.2 编写Eureka-server
1）导入依赖
1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
5 <parent>
6 <artifactId>cloud-demo</artifactId>
7 <groupId>com.myx.demo</groupId>
8 <version>1.0.0-SNAPSHOT</version>
9 </parent>
10 <modelVersion>4.0.0</modelVersion>
11
12 <groupId>com.myx.demo</groupId>
13 <artifactId>eureka-server</artifactId>
14
15 <dependencies>
16 <dependency>
17 <groupId>org.springframework.cloud</groupId>
18 <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
19 </dependency>
20 </dependencies>
21 </project>2）编写启动类
1 @SpringBootApplication
2 @EnableEurekaServer // 声明这个应用是一个EurekaServer
3 public class EurekaDemo {
4 public static void main(String[] args) {
5 SpringApplication.run(EurekaDemo.class);
6 }
7 }3）编写配置 application.yml
1 server:
2 port: 10086
3
4 spring:
5 application:
6 name: eureka-server # 应用名称，会在Eureka中显示
7
8 eureka:
9 client:
10 register-with-eureka: false # 是否注册自己的信息到EurekaServer，默认是true
11 fetch-registry: false # 是否拉取其它服务的信息，默认是true
12 service-url: # EurekaServer的地址，现在是自己的地址，如果是集群，需要加上其它Server的地址。
13 defaultZone: http://127.0.0.1:${server.port}/eureka2.3 创建user-service,并将其注册到Eureka
1）导入依赖
1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0"
3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
5 <parent>
6 <artifactId>cloud-demo</artifactId>
7 <groupId>com.myx.demo</groupId>
8 <version>1.0.0-SNAPSHOT</version>
9 </parent>
10 <modelVersion>4.0.0</modelVersion>
11
12 <groupId>com.myx.demo</groupId>
13 <artifactId>user-service</artifactId>
14
15 <dependencies>
16 <dependency>
17 <groupId>org.springframework.boot</groupId>
18 <artifactId>spring-boot-starter-web</artifactId>
19 </dependency>
20 <dependency>
21 <groupId>org.mybatis.spring.boot</groupId>
22 <artifactId>mybatis-spring-boot-starter</artifactId>
23 </dependency>
24 <dependency>
25 <groupId>mysql</groupId>
26 <artifactId>mysql-connector-java</artifactId>
27 </dependency>
28 <dependency>
29 <groupId>tk.mybatis</groupId>
30 <artifactId>mapper-spring-boot-starter</artifactId>
31 </dependency>
32 <!-- Eureka客户端 -->
33 <dependency>
34 <groupId>org.springframework.cloud</groupId>
35 <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
36 </dependency>
37 </dependencies>
38
39 </project>2）、编写配置 application.yml
1 server:
2 port: 8080
3 spring:
4 datasource:
5 url: jdbc:mysql://localhost:3306/day11mybatis
6 password: 123
7 username: root
8 application:
9 name: user-service #应用名称
10 eureka:
11 client:
12 service-url: # EurekaServer的地址，现在是自己的地址，如果是集群，需要加上其它Server的地址。
13 defaultZone: http://127.0.0.1:10086/eureka
14 instance:
15 prefer-ip-address: true # 当调用getHostname获取实例的hostname时，返回ip而不是host名称
16 ip-address: 127.0.0.1 # 指定自己的ip信息，不指定的话会自己寻找
17
18
19 logging:
20 level:
21 com.myx.demo:
22 debug3）编写启动类并开启Eureka客户端功能
1 @SpringBootApplication
2 @MapperScan("com.myx.demo.mapper")
3 @EnableDiscoveryClient //开启EurekaClient
4 public class UserApplication {
5 public static void main(String[] args) {
6 SpringApplication.run(UserApplication.class);
7 }
8 }4）实体类
1 @Table(name = "tb_user")
2 public class User {
3 @Id
4 @GeneratedValue(generator = "JDBC")
5 private Long id;
6 // 用户名
7 private String userName;
8 // 密码
9 private String password;
10 // 姓名
11 private String name;
12 // 年龄
13 private Integer age;
14 // 性别，1男性，2女性
15 private Integer sex;
16 // 出生日期
17 private Date birthday;
18 // 创建时间
19 private Date created;
20 // 更新时间
21 private Date updated;
22 //get、set方法...
23 }5)controller
1 @RestController
2 @RequestMapping("user")
3 public class UserController {
4 @Autowired
5 private UserService userService;
6
7 @GetMapping("/{id}")
8 public User queryById(@PathVariable("id") Long id) {
9 return this.userService.queryById(id);
10 }
11 }
6) service
1 @Service
2 public class UserService {
3 @Autowired
4 private UserMapper userMapper;
5 public User queryById(Long id){
6 return this.userMapper.selectByPrimaryKey(id);
7 }
8 }7)mapper接口
1 public interface UserMapper extends Mapper<User>{ }
2.4创建user-consumer,并让其获取Eureka服务
1）导入依赖
1 <dependencies>
2 <dependency>
3 <groupId>org.springframework.boot</groupId>
4 <artifactId>spring-boot-starter-web</artifactId>
5 </dependency>
6 <!-- 添加OkHttp支持 -->
7 <dependency>
8 <groupId>com.squareup.okhttp3</groupId>
9 <artifactId>okhttp</artifactId>
10 <version>3.9.0</version>
11 </dependency>
12
13 <dependency>
14 <groupId>org.springframework.cloud</groupId>
15 <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
16 </dependency>
17 </dependencies>2）编写application.yml
1 server:
2 port: 8081
3 spring:
4 application:
5 name: user-consumer # 应用名称
6
7
8 eureka:
9 client:
10 service-url: # EurekaServer地址
11 defaultZone: http://127.0.0.1:10086/eureka
12 instance:
13 prefer-ip-address: true # 当其它服务获取地址时提供ip而不是hostname
14 ip-address: 127.0.0.1 # 指定自己的ip信息，不指定的话会自己寻找
15
16 logging:
17 level:
18 com.myx.demo:
19 debug
3）编写启动类并开启Eureka客户端
1 @SpringBootApplication
2 @EnableDiscoveryClient //开启Eureka客户端
3 public class UserConsumer {
4 public static void main(String[] args) {
5 SpringApplication.run(UserConsumer.class);
6 }
7
8 //此时restTemplate的实现就是okHttp3
9 @Bean
10 public RestTemplate restTemplate(){
11 // 这次我们使用了OkHttp客户端,只需要注入工厂即可
12 return new RestTemplate(new OkHttp3ClientHttpRequestFactory());
13 }
14 }4)service
1 @Service
2 public class UserService {
3 @Autowired
4 private RestTemplate restTemplate;
5 @Autowired
6 private DiscoveryClient discoveryClient;
7 public List<User> queryUsersByIds(List<Long> ids) {
8 List<User> userList = new ArrayList<>();
9
10 //根据服务器的名称获取所有的服务实例
11 List<ServiceInstance> instances = discoveryClient.getInstances("user-service");
12 //因为只有一个UserService，因此我们直接get(0)获取
13 ServiceInstance instance = instances.get(0);
14 //获取主机名
15 String host = instance.getHost();
16 //获取端口号
17 int port = instance.getPort();
18 for (Long id : ids) {
19 User user = restTemplate.getForObject("http://"+host+":"+port+"/user/" + id, User.class);
20 userList.add(user);
21 }
22 return userList;
23 }5)mapper
1 @RestController
2 @RequestMapping("yun9")
3 public class UserMapper {
4
5 @Autowired
6 private UserService userService;
7
8 @GetMapping("users")
9 public List<User> queryUsersByIds(@RequestParam("ids") List<Long> ids){
10 List<User> userList = userService.queryUsersByIds(ids);
11 if (userList != null){
12 return userList;
13 }
14
15 return null;
16
17 }/*Spring提供了一个RestTemplate模板工具类，对基于Http的客户端进行了封装，并且实现了对象与json的序列化和反序列化，非常方便。RestTemplate并没有限定Http的客户端类型，
而是进行了抽象，目前常用的3种都有支持：
- HttpClient
- OkHttp
- JDK原生的URLConnection（默认的）*/
来源：oschina
链接：https://my.oschina.net/u/4336274/blog/3718823