微服务之初体验（1）

一、创建父项目

创建一个 Maven 项目，

命名为 springcloud-0，

删掉 src ，使之成为空的父项目，

1. pom 文件

配置父项目 pom 文件，其中，将版本号提出来，可以方便后面更改。

<?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>org.example</groupId>
    <artifactId>springcloud-0</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>pom</packaging> <!-- 打包 -->

    <properties>
        <junit.version>4.12</junit.version>
        <lombok.version>1.18.10</lombok.version>
        <log4j.version>1.2.17</log4j.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!-- springcloud 依赖 -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- springboot -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.1.4.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- MySQL -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.28</version>
            </dependency>
            <!-- Druid -->
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.1.10</version>
            </dependency>
            <!-- mybatis -->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.4</version>
            </dependency>
            <!-- Junit -->
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version> <!-- 引用上面定义的 -->
            </dependency>
            <!-- lombok -->
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
            </dependency>
            <!-- log4j -->
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
            <!-- logback -->
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
                <version>1.2.3</version>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

二、数据库

连接数据库，

可能要配置时区，

点击 Advanced 找到 serverTimezone 填上 UTC 然后 Apply、连接即可。

勾选 db01 数据库，没有就自己新建一个，

在 db01 新建部门表，

相关SQL语句如下：

create table dept
(
	deptno bigint auto_increment,
	dname varchar(60) null,
	db_source varchar(60) null,
	constraint dept_pk
		primary key (deptno)
)
comment '部门表';

三、子模块

（一）、springcloud-api 模块

接下来，在父项目新建一个 module。

还是和之前一样创建一个 Maven 项目，

可以看到父项目依赖里，自动引用了模块 springcloud-api，

1. pom 文件

在 springcloud-api 模块的 pom 文件配置依赖，

<?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">
    <parent>
        <artifactId>springcloud-0</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-api</artifactId>
    <!-- 父项目依赖已导入，无需版本号，将会直接指向父项目依赖 -->
    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
</project>

2. pojo 层

接着，可以按照数据库写实体类了。

Dept 代码：

package com.zh.pojo;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;
import java.io.Serializable;

@Data
@NoArgsConstructor
@Accessors(chain = true) // 链式编程
public class Dept implements Serializable {
    private long deptno;
    private String dname;
    private String db_source;

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

此模块功能就到此结束，继续创建下一模块。

（二）、springcloud-provider-dept-8001 模块

1. pom 文件

与之前一样，向 springcloud-provider-dept-8001 模块的 pom 文件导入依赖，

<?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">
    <parent>
        <artifactId>springcloud-0</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-provider-dept-8001</artifactId>
	<!-- springcloud-api模块 -->
    <dependencies>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</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-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>
</project>

2. yaml 文件

在 resources 目录下编写 application.yaml 文件，

## 端口号
server:
  port: 8001

mybatis:
  type-aliases-package: com.zh.pojo
  config-location: classpath:mybatis/mybatis-config.xml
  mapper-locations: classpath:mybatis/mapper/*.xml

spring:
  application:
    name: springcloud-provider-dept
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/db01?characterEncoding=utf-8&serverTimezone=UTC&useUnicode=true
    username: root
    password: 123456

3. Dao 层

编写 Dao 层，DeptDao 接口类代码如下：

package com.zh.dao;
import com.zh.pojo.Dept;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import java.util.List;

@Mapper
@Repository
public interface DeptDao {
    public boolean addDept(Dept dept);// 添加
    public Dept queryById(Long id);// 通过id查询
    public List<Dept> queryAll();// 查询所有数据
}

mybatis 配置文件：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <settings><!-- 开启二级缓存 -->
        <setting name="cacheEnabled" value="true"/>
    </settings>
</configuration>

编写 DeptMapper 文件：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.zh.dao.DeptDao">
    <insert id="addDept" parameterType="Dept">
        insert into dept (dname, db_source) values (#{dname},DATABASE());
    </insert>
    <select id="queryById" parameterType="Long" resultType="Dept">
        select * from dept where deptno = #{deptno};
    </select>
    <select id="queryAll" resultType="Dept">
        select * from dept;
    </select>
</mapper>

4. Service 层

DeptService 接口类：

package com.zh.service;
import com.zh.pojo.Dept;
import java.util.List;
public interface DeptService {
    public boolean addDept(Dept dept);
    public Dept queryById(Long id);
    public List<Dept> queryAll();
}

DeptServiceImpl 实现类：

package com.zh.service;
import com.zh.dao.DeptDao;
import com.zh.pojo.Dept;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;

@Service
public class DeptServiceImpl implements DeptService {
    @Autowired
    private DeptDao deptDao;
    public boolean addDept(Dept dept) {
        return deptDao.addDept(dept);
    }
    public Dept queryById(Long id) {
        return deptDao.queryById(id);
    }
    public List<Dept> queryAll() {
        return deptDao.queryAll();
    }
}

5. Controller 层

DeptController 类：

package com.zh.controller;
import com.zh.pojo.Dept;
import com.zh.service.DeptService;
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.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RestController
public class DeptController {
    @Autowired
    private DeptService deptService;

    @PostMapping("/dept/add")
    public boolean addDept(Dept dept){
        return deptService.addDept(dept);
    }
    @GetMapping("/dept/get/{id}")
    public Dept get(@PathVariable("id") Long id){
        return deptService.queryById(id);
    }
    @PostMapping("/dept/list")
    public List<Dept> queryAll(){
        return deptService.queryAll();
    }
}

四、测试

最后，编写 DeptProvider_8001 启动类：

package com.zh;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DeptProvider_8001 {
    public static void main(String[] args) {
        SpringApplication.run(DeptProvider_8001.class,args);
    }
}

运行项目，浏览器输入 localhost:8001/dept/get/1 查看效果，

如果还想测试另外两个（添加、查所有），则需在 DeptController 类中将 @PostMapping 改为 @GetMapping。