簡介

目錄

1.建立一個Maven專案，他的ArtifactId是microservice-simple-provider-user，pom.xml的內容如下：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd"
 
>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.itmuch.cloud</groupId>
  <artifactId>microservice-simple-provider-user</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <!-- 引入spring boot的依賴 -->
  <parent>
 

    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.RELEASE</version>
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <
 
java.version>1.8</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
  </dependencies>

  <!-- 引入spring cloud的依賴 -->
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>Edgware.RELEASE</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>

  <!-- 新增spring-boot的maven外掛 -->
  <build>
    <plugins>
      <plugin>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-maven-plugin</artifactId>
      </plugin>
    </plugins>
  </build>
</project>

其中，Spring-boot-starter-web提供了SpringMVC的支援； spring-boot-starter-data-jpa提供了Spring Data JPA的支援。

2.準備好建表語句，在專案的classpath下建立schema.sql，並新增如下內容：

	drop table user if exists;
	create table user (id bigint generated by default as identity, username varchar(40),
	name varchar(20), age int(3), balance decimal(10,2), primary key (id));

3. 準備幾條資料,在專案的classpath下建立data.sql，並新增如下內容：

	insert into user(id,username,name,age,balance)values(1,'account1','張三',20,100.00);
	insert into user(id,username,name,age,balance)values(2,'account2','李四',28,180.00);
	insert into user(id,username,name,age,balance)values(3,'account3','王五',32,280.00);

4.建立使用者實體類User

public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @Column
    private String username;
    @Column
    private String name;
    @Column
    private Integer age;
    @Column
    private BigDecimal balance;

	//getters and setters
    public Long getId() { return id;}
    public void setId(Long id) {this.id = id;}
    public String getUsername() { return username; }
    public void setUsername(String username) { this.username = username;}
    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;}
    public BigDecimal getBalance() { return balance; }
    public void setBalance(BigDecimal balance) {this.balance = balance; }
}

5.建立DAO（注意型別是Interface）UserRepositotry

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

6.建立UserController

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


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

之前書上寫的是User findOne = this.userRepository.findOne(id);

但是springboot方法報錯是因為用的版本高，可以將它改為 this.userRepository.findById(id).get()或者 this.userRepository.findById(id).orElse(null)

7.編寫啟動類ProviderUserRepository，在類上使用@SpringBootApplication宣告這是一個SpringBoot專案。

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

8.編寫配置檔案，命名為application.yml。

server:
    port: 8000
Spring:
    jpa:
        generate-ddl: false
        show-sql: true
        hibernate:
            ddl-auto: none
    datasource:                         #指定資料來源
        platform: h2                    #指定資料來源型別
        schema: classpath:schema.sql    #指定mysql資料庫的建表指令碼
        data: classpath:data.sql        #指定mysql資料庫的資料指令碼
logging:                               # 配置日誌級別，讓hibernate打印出執行的SQL
     level:
        root: INFO
        org.hibernate: INFO
        org.hibernate.type.descriptor.sql.BasicBinder: TRACE
        org.hibernate.type.descriptor.sql.BasicExtractor: TRACE
 

小知識點：Spring Boot以及Spring Cloud 支援使用yml格式檔案或properties格式檔案。

9.最後訪問網頁 localhost:8000/1，結果如下

本文大部分內容轉載自周立的《Spring Cloud與Docker微服務架構實戰》