springcloud(二)-最简单的实战

技术储备

Spring cloud并不是面向零基础开发人员，它有一定的学习曲线。

• 语言基础：spring cloud是一个基于Java语言的工具套件，所以学习它需要一定的Java基础。当然，spring cloud同样也支持使用Scala,Groovy等语言进行开发。
• Spring boot：Spring cloud是基于spring boot构建的，因此它延续了spring boot的契约模式以及开发模式。学习spring cloud之前需要学习spring boot，至少先入门。
• 项目管理与构建工具：目前业界比较主流的项目管理与构建工具有maven和Gradle等，我想大家最常用的，或者说用的最多的还是maven吧。

工具及软件版本

• JDK：springboot官方推荐使用的是JDK１.８，当然Spring cloud推荐的也是JDK１.８。所以你懂的呀，不用纠结低版本的了呀。
• Spring boot：使用Spring Boot 1.5.9.RELEASE。虽然现在Spring boot2.0出来了，但是需要结合Spring cloud的版本兼容。
• Spring cloud：使用 Spring Cloud Edgware RELEASE.（你要想用最新的也没问题，但是要注意springboot兼容性）
• maven：我用的是3.5.0啊。无所谓
• 开发工具：我独爱eclipse。虽然我知道IntelliJ IDEA 可能更优秀。

服务的提供者与服务的消费者

使用微服务构建的是分布式系统，微服务之间通过网络进行通信。我们使用服务提供者与服务消费者来描述为服务之间的调用关系。

举个生活中的例子：我们去超市买东西，商品又是由厂商提供给超市的。在这一过程中，厂商就是服务的提高者，超市是服务的消费者。

我们只需要到超市消费就行，不用到厂商去了。

编写服务提供者

先准备下数据库和数据

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `username` varchar(40) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL,
  `age` int(3) DEFAULT NULL,
  `balance` decimal(10,2) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of user
-- ----------------------------
INSERT INTO `user` VALUES (‘1‘, ‘account1‘, ‘张三‘, ‘20‘, ‘98.23‘);
INSERT INTO `user` VALUES (‘2‘, ‘account2‘, ‘李四‘, ‘24‘, ‘23.12‘);
INSERT INTO `user` VALUES (‘3‘, ‘account3‘, ‘王五‘, ‘32‘, ‘42.12‘);

创建一个springboot项目，ArtifactId为microservice-simple-provider-user

pom.xml

 1 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 2   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 3   <modelVersion>4.0.0</modelVersion>
 4
 5   <groupId>com.itmuch.cloud</groupId>
 6   <artifactId>microservice-simple-provider-user</artifactId>
 7   <version>0.0.1-SNAPSHOT</version>
 8   <packaging>jar</packaging>
 9
10   <name>microservice-simple-provider-user</name>
11   <url>http://maven.apache.org</url>
12
13   <parent>
14         <groupId>org.springframework.boot</groupId>
15         <artifactId>spring-boot-starter-parent</artifactId>
16         <version>1.5.9.RELEASE</version>
17     </parent>
18
19   <properties>
20     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
21     <java.version>1.8</java.version>
22   </properties>
23
24   <dependencies>
25            <dependency>
26             <groupId>org.springframework.boot</groupId>
27             <artifactId>spring-boot-starter-web</artifactId>
28         </dependency>
29         <dependency>
30                <groupId>mysql</groupId>
31                <artifactId>mysql-connector-java</artifactId>
32         </dependency>
33         <dependency>
34             <groupId>org.springframework.boot</groupId>
35             <artifactId>spring-boot-devtools</artifactId>
36             <optional>true</optional> <!-- 这个需要为 true 热部署才有效 -->
37         </dependency>
38         <!-- jpa-->
39         <dependency>
40             <groupId>org.springframework.boot</groupId>
41             <artifactId>spring-boot-starter-data-jpa</artifactId>
42         </dependency>
43   </dependencies>
44
45 <!--   引入spring cloud 的依赖 -->
46     <dependencyManagement>
47         <dependencies>
48             <dependency>
49                 <groupId>org.springframework.cloud</groupId>
50                 <artifactId>spring-cloud-dependencies</artifactId>
51                 <version>Edgware.RELEASE</version>
52                 <type>pom</type>
53                 <scope>import</scope>
54             </dependency>
55         </dependencies>
56     </dependencyManagement>
57
58 <!--   添加spring-boot 的maven插件 -->
59     <build>
60         <plugins>
61             <plugin>
62                 <groupId>org.springframework.boot</groupId>
63                 <artifactId>spring-boot-maven-plugin</artifactId>
64             </plugin>
65         </plugins>
66     </build>
67
68 </project>

点击展开

用户实体类User.java

 1 package com.itmuch.cloud.entity;
 2
 3 import java.math.BigDecimal;
 4
 5 import javax.persistence.Entity;
 6 import javax.persistence.GeneratedValue;
 7 import javax.persistence.GenerationType;
 8 import javax.persistence.Id;
 9
10 @Entity
11 public class User {
12     @Id
13     @GeneratedValue(strategy = GenerationType.AUTO)
14     private Long id;
15     private String username;
16     private String name;
17     private Integer age;
18     private BigDecimal balance;
19
20     public Long getId() {
21         return id;
22     }
23
24     public void setId(Long id) {
25         this.id = id;
26     }
27
28     public String getUsername() {
29         return username;
30     }
31
32     public void setUsername(String username) {
33         this.username = username;
34     }
35
36     public String getName() {
37         return name;
38     }
39
40     public void setName(String name) {
41         this.name = name;
42     }
43
44     public Integer getAge() {
45         return age;
46     }
47
48     public void setAge(Integer age) {
49         this.age = age;
50     }
51
52     public BigDecimal getBalance() {
53         return balance;
54     }
55
56     public void setBalance(BigDecimal balance) {
57         this.balance = balance;
58     }
59
60 }

点击展开

DAO

package com.itmuch.cloud.dao;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import com.itmuch.cloud.entity.User;

@Repository
public interface UserRepository extends JpaRepository<User, Long> {

}

创建Controller

package com.itmuch.cloud.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import com.itmuch.cloud.dao.UserRepository;
import com.itmuch.cloud.entity.User;

@RestController
public class UserController {
    @Autowired
    private UserRepository userRepository;

    @GetMapping("/{id}")
    public User findById(@PathVariable Long id) {
        User findOne = userRepository.findOne(id);
        return findOne;
    }
}

最后还有一个启动类不用说了吧。

配置文件application.yml

server:
  port: 8084
spring:
  application:
    name: microservice-provider-user
  jpa:
    generate-ddl: false
    show-sql: true
    database-platform: org.hibernate.dialect.MySQL5Dialect
    hibernate:
      ddl-auto: none
  datasource:
    url: jdbc:mysql://localhost:3306/cloud?useUnicode=true&characterEncoding=UTF-8
    username: root
    password: 1234
    driver-class-name: com.mysql.jdbc.Driver
  http:
    multipart:
      maxFileSize: 100Mb
      maxRequestSize: 100Mb
logging:
  level:
    root: INFO
    org.hibernate: INFO
    org.hibernate.type.descriptor.sql.BasicBinder: TRACE
    org.hibernate.type.descriptor.sql.BasicExtractor: TRACE

测试

启动访问localhost:8084/1. 试下结果。

{"id":1,"username":"account1","name":"张三","age":20,"balance":98.23}

哦了。

编写服务消费者

创建一个maven项目，ArtifactId是microservice-simple-consumer-movie.

pom.xml

一样一样的。

POJO类User.java

 1 package com.itmuch.cloud.pojo;
 2
 3 import java.math.BigDecimal;
 4
 5 public class User {
 6     private Long id;
 7     private String username;
 8     private String name;
 9     private Integer age;
10     private BigDecimal balance;
11
12     public Long getId() {
13         return id;
14     }
15
16     public void setId(Long id) {
17         this.id = id;
18     }
19
20     public String getUsername() {
21         return username;
22     }
23
24     public void setUsername(String username) {
25         this.username = username;
26     }
27
28     public String getName() {
29         return name;
30     }
31
32     public void setName(String name) {
33         this.name = name;
34     }
35
36     public Integer getAge() {
37         return age;
38     }
39
40     public void setAge(Integer age) {
41         this.age = age;
42     }
43
44     public BigDecimal getBalance() {
45         return balance;
46     }
47
48     public void setBalance(BigDecimal balance) {
49         this.balance = balance;
50     }
51
52 }

点击展开

Controller类

 1 package com.itmuch.cloud.controller;
 2
 3 import org.springframework.beans.factory.annotation.Autowired;
 4 import org.springframework.web.bind.annotation.GetMapping;
 5 import org.springframework.web.bind.annotation.PathVariable;
 6 import org.springframework.web.bind.annotation.RestController;
 7 import org.springframework.web.client.RestTemplate;
 8
 9 import com.itmuch.cloud.pojo.User;
10
11 @RestController
12 public class MovieController {
13     @Autowired
14     private RestTemplate restTemplate;
15
16     @GetMapping("/user/{id}")
17     public User findById(@PathVariable Long id) {
18         return restTemplate.getForObject("http://localhost:8084/" + id, User.class);
19     }
20 }

点击展开

启动类

 1 package com.itmuch.cloud;
 2
 3 import org.springframework.boot.SpringApplication;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 import org.springframework.context.annotation.Bean;
 6 import org.springframework.web.client.RestTemplate;
 7
 8 @SpringBootApplication
 9 public class ConsumerMovieApplication {
10     @Bean
11     public RestTemplate restTemplate() {
12         return new RestTemplate();
13     }
14
15     public static void main(String[] args) {
16         SpringApplication.run(ConsumerMovieApplication.class, args);
17     }
18 }

点击展开

配置文件application.yml

server:
  port: 8082

测试

好了，你把两个服务都启动，访问http://127.0.0.1:8082/user/1, 看结果。

{"id":1,"username":"account1","name":"张三","age":20,"balance":98.23}

OK了。

原文地址：https://www.cnblogs.com/fengyuduke/p/10552885.html