SpringCloud之Rest微服务入门案例

构建SpringCloud工程
概述：SpringCloud工程由一个父工程和若干个Module组成

==应该遵循的条件：约定 > 配置 > 编码==

构建父工程
- 创建一个Maven父工程并命名为spring-cloud
- 打包方式为==POM==
- 在pom.xml中定义各依赖的版本号（若Module中pom.xml的依赖没有指定版本号，则会根据父工程的版本号加入依赖）

- 加入通用的依赖和插件

<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.zhou</groupId>
  <artifactId>spring-cloud</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>pom</packaging>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <junit.version>4.12</junit.version>
    <log4j.version>1.2.17</log4j.version>
    <lombok.version>1.16.18</lombok.version>
  </properties>
  <dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Dalston.SR1</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-dependencies</artifactId>
            <version>1.5.9.RELEASE</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.0.4</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.31</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.0</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-core</artifactId>
            <version>1.2.3</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
    </dependencies>
  </dependencyManagement>
</project>

构建Module

- 在父工程下新建Maven的Module，打包方式为jar
- 在该Module下pom.xml中加入其它需要的依赖
- 正常开发即可
- 完成后先clean一下Maven项目，然后再install提供给其它模块调用

创建公共子模块Module(spring-cloud-api)

<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>
  <parent>
    <groupId>com.zhou</groupId>
    <artifactId>spring-cloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>spring-cloud-api</artifactId>
  <dependencies>
    <!-- 当前Module需要用到的jar包,按自己需要添加,如果父类已经包含了,可以不要写版本号 -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
  </dependencies>
</project>

@SuppressWarnings("serial")
@AllArgsConstructor
@NoArgsConstructor
@Data
@Accessors(chain=true)//链式访问，该注解设置chain=true，生成setter方法返回this，代替了默认的返回void
public class Dept implements Serializable{//必须序列化
    private Long deptno;
    private String dname;
    // 来自哪个数据库,因为微服务架构可以一个服务对应一个数据库,
    // 同一个信息被存储到不同数据库
    private String db_source;

    // 第一种方式:
    // 无参和全参构造函数
    // getter,setter和toString 方法

    // 第二种方式: 使用lombok,使用注解
    // Eclipse 需要安装lombok插件
}

// mvn clean install 后给其他模块引用,达到通用目的;
// 即需要用到部门实体的话,不用每个工程都定义一份,直接引用本模块即可;

添加其它Module的依赖方法
- 直接引用其即可

    <dependencies>
        <dependency>
            <groupId>com.zhou</groupId>
            <artifactId>spring-cloud-api</artifactId>
            <version>${project.version}</version>
        </dependency>
    </dependencies>

部门微服务提供者Module(spring-cloud-provider-dept-8001)

<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>
  <parent>
    <groupId>com.zhou</groupId>
    <artifactId>spring-cloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>spring-cloud-provider-dept-8001</artifactId>
  <dependencies>
    <dependency>
        <groupId>com.zhou</groupId>
        <artifactId>spring-cloud-api</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</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-jetty</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-test</artifactId>
    </dependency>
    <!-- 修改后立即生效,热部署 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>springloaded</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
    </dependency>
  </dependencies>
</project>

配置该module下的yml
- 微服务需要独立的端口
- ==微服务最重要的是取名字！！！！一定要给微服务配置一个名字！这个名字就是这个微服务对外暴露的名字！==

- 配置该模块下的其它相关配置（如本例配置了mybatis）

// src/main/resources/application.yml

server:
  port: 8081

mybatis:
   config-location: classpath:mybatis/mybatis.cfg.xml      # mybatis配置文件所在路径
   type-aliases-package: com.zhou.springcloud.entities  # 所有Entity别名类所在包
   mapper-locations:
   - classpath:mybatis/mapper/**/*.xml

spring:
   application:
     name: spring-cloud-dept    #为这个服务取名，非常重要！！！！！
   datasource:
     type: com.alibaba.druid.pool.DruidDataSource           # 当前数据源操作类型
     driver-class-name: org.gjt.mm.mysql.Driver             # mysql驱动包
     url: jdbc:mysql://localhost:3306/cloudDB01             # 数据库名称
     username: root
     password: root
     dbcp2:
       min-idle: 5
       initial-size: 5
       max-total: 5
       max-wait-millis: 200

// src/main/sources/mybatis/mybatis.cfg.xml

<?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>

// com.zhou.springcloud.dao

@Mapper
public interface DeptDao {
    public boolean addDept(Dept dept);

    public Dept findById(Long id);

    public List<Dept> findAll();
}

// src/main/sources/mybatis/mapper/DeptMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.zhou.springcloud.dao.DeptDao">

    <select id="findById" resultType="Dept" parameterType="Long">
        select deptno,dname,db_source from dept where deptno=#{deptno};
    </select>
    <select id="findAll" resultType="Dept">
        select deptno,dname,db_source from dept;
    </select>
    <insert id="addDept" parameterType="Dept">
    INSERT INTO dept(dname,db_source) VALUES(#{dname},DATABASE());
    </insert>

</mapper>

// DeptService部门服务接口

public interface DeptService {
    public boolean add(Dept dept);
    public Dept get(Long id);
    public List<Dept> list();
}

// DeptServiceImpl部门服务接口实现类

@Service
public class DeptServiceImpl implements DeptService{

    @Autowired
    private DeptDao deptDao;

    @Override
    public boolean add(Dept dept) {

        return deptDao.addDept(dept);
    }

    @Override
    public Dept get(Long id) {

        return deptDao.findById(id);
    }

    @Override
    public List<Dept> list() {

        return dptDao.findAll();
    }
}

//DeptController部门微服务提供者REST

@RestController
public class DeptController {

    @Autowired
    private DeptService deptService;

    @RequestMapping(value="/dept/add",method=RequestMethod.POST)
    public boolean add(@RequestBody Dept dept) {
        return deptService.add(dept);
    }

    @RequestMapping(value="/dept/get/{id}",method=RequestMethod.GET)
    public Dept get(@PathVariable("id") Long id) {
        return deptService.get(id);
    }

    @RequestMapping(value="/dept/list",method=RequestMethod.GET)
    public List<Dept> get() {
        return deptService.list();
    }
}

// DeptProvider8001_App主动启动类DeptProvider8001_App

- 记得主启动类放在根包下,com.xxx.xxx

@SpringBootApplication
public class DeptProvider8001_App {

    public static void main(String[] args) {
        SpringApplication.run(DeptProvider8001_App.class, args);
    }
}

部门微服务消费者Module(spring-cloud-consumer-dept-80)

<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>
  <parent>
    <groupId>com.zhou</groupId>
    <artifactId>spring-cloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>spring-cloud-consumer-dept-80</artifactId>
  <dependencies>
    <dependency>
        <groupId>com.zhou</groupId>
        <artifactId>spring-cloud-api</artifactId>
        <version>${project.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <!-- 修改后立即生效,热部署 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>springloaded</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
    </dependency>
  </dependencies>
</project>

// application.yml
server:
  port: 80

// com.zhou.springcloud.cfgbeans

// ConfigBean 类(作用类似Spring里面的applicationContext.xml写入的注入Bean)
@Configuration
public class ConfigBean{
    @Bean
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }
}

// 新建DeptController_Consumer部门微服务消费者REST

// com.zhou.springcloud.controller

@RestController
public class DeptController_Consumer {

    private static final String REST_URL_PREFIX = "http://localhost:8081";

    /**
     * 使用restTemplate访问restful接口:
     * (url, requestMap, ResponseBean.class)这三个参数分别代表:
     * REST请求地址,请求参数,HTTP响应被转换成的对象类型
     */
    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping(value="/consumer/dept/add")
    public boolean add(Dept dept) {
        return restTemplate.postForObject(REST_URL_PREFIX+"/dept/add", dept, Boolean.class);
    }

    @RequestMapping(value="/consumer/dept/get/{id}")
    public Dept get(@PathVariable("id") Long id) {
        return restTemplate.getForObject(REST_URL_PREFIX+"/dept/get/"+id, Dept.class);
    }

    @SuppressWarnings("unchecked")
    @RequestMapping(value="/consumer/dept/list")
    public List<Dept> list() {
        return restTemplate.getForObject(REST_URL_PREFIX+"/dept/list", List.class);
    }
}

RestTemplate类
#### 介绍
RestTemplate是Spring提供的用于访问Rest服务的客户端模板工具集，提供了多种远程访问Http的方法
[RestTemplate的API]: https://docs.spring.io/spring/docs/5.0.6.RELEASE/javadoc-api/
#### 意义
在一些不涉及实现方法的模块中（消费者），只需要调用其他服务暴露出的接口即可满足的需求，使用RestTemplate类中的方法可以发出需要的HTTP请求并得到返回结果。（类似Ajax）

#### RestTemplate用法

RestTemplate restTemplate = new RestTemplate();
//url:请求地址
//requestMap:请求参数
//type.class:HTTP响应转换成的对象类型
restTemplate.getForObject(url,type.class);
restTemplate.postForObject(url,requestMap,type.class);

// com.zhou.springcloud
// DeptConsumer80_App 主启动类

@SpringBootApplication
public class DeptConsumer80_App {

    public static void main(String[] args) {

        SpringApplication.run(DeptConsumer80_App.class, args);
    }

}

// 测试:// 访问:// http://localhost:80/consumer/dept/get/2
// http://localhost:80/consumer/dept/list

SpringCloud之Rest微服务入门案例

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