SpringCloud:Rest Api~~基於http的遠程調用解決方案

什么是Rest

REST是Representational State Transfer的縮寫，它是由羅伊·菲爾丁（Roy Fielding）提出的，是用來描述創建HTTP API的標准方法的，他發現這四種常用的行為（查看（view），創建（create），編輯（edit）和刪除（delete））都可以直接映射到HTTP 中已實現的GET,POST,PUT和DELETE方法。

在實際應用上就是在controller層根據訪問不同業務，去指定請求類型，如常用的post，get

 

什么是Api

全稱Application Programming Interface（應用程序j接口）

 

什么是Rest Api

基於上述兩個知識點就很好理解了，就是一個http的遠程調用解決方案，它提供restTemplate等接口

目的：在微服務架構中的作用是讓各微服務之間產生聯系，方便調用

本質：基於http的具備restful風格的遠程調用的接口，

什么是遠程調用：建議看我的dubbo原理篇博客！！！

下面開始去做一個基於rest api的微服務架構

 

Rest學習環境搭建與測試

建一個maven（不要模板）項目，作為父項目

目的：將所有子項目的依賴到導入父項目中，控制各依賴項目的版本，解決了分布式項目中依賴版本不兼容問題

導入相關依賴

<?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.king</groupId>
    <artifactId>SpringCloudLearns</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>springcloud-api</module>
        <module>springcloud-provider-dept-8001</module>
        <module>springcloud-consumer-dept-80</module>
    </modules>

    <!--打包方式pom，默認的是jar-->
    <packaging>pom</packaging>

    <!--配置-->
    <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>
    <!--    <lombok.version>1.8.10</lombok.version>-->
        <log4j.version>1.2.17</log4j.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!--springCloud的依賴-->
            <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-dependencies -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR3</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>

            <!--數據庫-->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>8.0.15</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>1.2.3</version>
            </dependency>

            <!--SpringBoot啟動器-->
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>1.3.2</version>
            </dependency>

            <!--日志測試-->
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
                <version>1.2.3</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.16</version>
            </dependency>
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
        </dependencies>
    </dependencyManagement>

</project>

 

建立各業務模塊

每個模塊都是獨立的一個微服務，通過改port，讓他們能在一個tomcat中獨立運行

 

涉及到的模塊：

1.api（關注pojo）

導入相關依賴

<?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>SpringCloudLearns</artifactId>
        <groupId>com.king</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-api</artifactId>

    <!--導入的是父類的已有的依賴，用的是<dependencyManagement>所以要自己導-->
    <!--微服務架構中盡量在父項目中導依賴，為了版本一致-->
    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>

</project>

實體類

//所有分布式架構的實體類都要先序列化
@Data
@NoArgsConstructor
@Accessors(chain = true) //鏈式寫法
/*鏈式編程例子
* Dept dept = new Dept
* dept.setdname('11').setdeptno(1);
* */
public class Dept implements Serializable {

    private Long deptno;
    private String dname;

    //記錄數據庫來源，一個服務對應一個數據庫
    private String db_source;


    //第一個主鍵自增，第三個數據庫函數，數據庫自動獲取，自動生成
    public Dept(String dme) {
        this.dname = dname;
    }

}

 

2.服務端（關注點：業務~model）

相關依賴

<?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>SpringCloudLearns</artifactId>
        <groupId>com.king</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-provider-dept-8001</artifactId>

    <dependencies>
        <!--需要拿到實體類，所以需要配置api module-->
        <dependency>
            <groupId>com.king</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </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>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!--jetty-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
        <!--熱部署工具-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>

    </dependencies>


</project>

yaml 配置（數據庫，mybatis，port配置）

server:
  port: 8001

#mybatis配置
mybatis:
  mapper-locations: classpath*:mybatis/mapper/*.xml
  type-aliases-package: com.king.springcloud.pojo


#spring配置
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/springcloudlearns?useSSL=false&serverTimezone=UTC&useUnicode=true&characterEncoding=UTF-8
    username: root
    password: 123456

mapper

@Mapper
@Repository
public interface DeptMapper {

    boolean addDept(Dept dept);

    Dept queryById(@Param("deptno") Long id);

    List<Dept> queryAll();

}

mapper.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.king.springcloud.mapper.DeptMapper">

    <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>

service接口

public interface DeptService {

    boolean addDept(Dept dept);

    Dept queryById(Long id);

    List<Dept> queryAll();

}

serviceImpl

@Service
public class DeptServiceImpl implements DeptService{

    @Autowired
    private DeptMapper deptMapper;

    @Override
    public boolean addDept(Dept dept) {
        return deptMapper.addDept(dept);
    }

    @Override
    public Dept queryById(Long id) {
        return deptMapper.queryById(id);
    }

    @Override
    public List<Dept> queryAll() {
        return deptMapper.queryAll();
    }
}

創建主啟動類

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

 

3.客戶端（關注點：view~controller）重要

maven依賴

<?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>SpringCloudLearns</artifactId>
        <groupId>com.king</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>springcloud-consumer-dept-80</artifactId>

    <!--實體類+web-->
    <dependencies>
        <dependency>
            <groupId>com.king</groupId>
            <artifactId>springcloud-api</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
        </dependency>
    </dependencies>


</project>

配置端口號：80（）客戶端一般都是80

 

RestTemplate不是spring的組件所以要去配置（@Bean）

//@Configuration,相當於spring中的applicationContext.xml
@Configuration
public class ConfigBean {

    @Bean
    public RestTemplate getRestTemplate(){
         return new RestTemplate();
    }

}

controller

@RestController
public class DeptConsumerController {

    //理解：消費者不應該又service層~,那么怎么去調用其他服務器端的服務呢？
    //解決：遠程調用，RestTemplate基於http的遠程調用接口服務，注冊到spring中
    //(url,實體：Map，class<T>responseType)
    @Autowired
    private RestTemplate restTemplate;

    private static final String REST_URL_PREFIX = "http://localhost:8001";

    @RequestMapping("/consumer/dept/add/{dname}")
    public Boolean add(@PathVariable("dname") String dname){
        System.out.println(dname);
        Dept dept = new Dept();
        dept.setDname(dname);
        return restTemplate.postForObject(REST_URL_PREFIX+"dept/add",dept,Boolean.class);
    }

    //http://localhost:8001/dept/get/{id}
    @RequestMapping("/consumer/dept/get/{id}")
    public Dept get(@PathVariable("id")Long id){
        //遠程調用，
        return restTemplate.getForObject(REST_URL_PREFIX+"/dept/get/"+id,Dept.class);
    }

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


}

創建主啟動類

@SpringBootApplication
public class DeptConsumer_80 {
    public static void main(String[] args) {
        SpringApplication.run(DeptConsumer_80.class,args);
    }
}

 

總結：

本次客戶端遠程調用服務端測試采用的是aop思想；