SpringCloud_Feign和RestTemplate和Restful

SpingCloud中使用RESTful风格编程有何作用？

        简而言之，使用RESTful风格编程可以通过选择不同的请求发送方式（Get、Post、Put、Delete），来代替书写不同的访问路径，较为简洁

一.创建服务提供者Provider

1.导入依赖

1.  
   <!--引用SpringCloud-API模块-->
2.  
   <!--Dept实体类所在模块-->
3.  
   <dependency>
4.  
   <groupId>org.example</groupId>
5.  
   <artifactId>SpringCloud-API</artifactId>
6.  
   <version>1.0-SNAPSHOT</version>
7.  
   </dependency>
8.  
   <!--spring boot web依赖-->
9.  
   <dependency>
10.  
    <groupId>org.springframework.boot</groupId>
11.  
    <artifactId>spring-boot-starter-web</artifactId>
12.  
    <version>2.6.7</version>
13.  
    </dependency>
14.  
    <!--mysql及mybatis依赖-->
15.  
    <dependency>
16.  
    <groupId>mysql</groupId>
17.  
    <artifactId>mysql-connector-java</artifactId>
18.  
    </dependency>
19.  
    <dependency>
20.  
    <groupId>org.mybatis.spring.boot</groupId>
21.  
    <artifactId>mybatis-spring-boot-starter</artifactId>
22.  
    </dependency>
23.  
    <!--热部署依赖-->
24.  
    <dependency>
25.  
    <groupId>org.springframework.boot</groupId>
26.  
    <artifactId>spring-boot-devtools</artifactId>
27.  
    <version>2.6.7</version>
28.  
    </dependency>

2.编写主启动类  

注：记得添加@SpringBootApplication注解

1.  
   @SpringBootApplication
2.  
   public class DeptProvider_8001 {
3.  
   public static void main(String[] args) {
4.  
   SpringApplication.run(DeptProvider_8001.class,args);
5.  
   }
6.  
   }

3.编写DAO层

注：记得添加@Mapper注解

1.  
   @Mapper
2.  
   public interface DeptMapper {
3.  
   Dept queryByDeptNo(Long deptno);
4.  
    
5.  
   List<Dept> queryAll();
6.  
    
7.  
   boolean addDept(Dept dept);
8.  
    
9.  
   boolean updateDept(Dept dept);
10.  
     
11.  
    boolean deleteDept(Long deptno);
12.  
    }

4.编写Server层

1.  
   public interface DeptService {
2.  
   Dept queryByDeptNo(Long deptno);
3.  
    
4.  
   List<Dept> queryAll();
5.  
    
6.  
   boolean addDept(Dept dept);
7.  
    
8.  
   boolean updateDept(Dept dept);
9.  
    
10.  
    boolean deleteDept(Long deptno);
11.  
    }

注：实现类上记得添加@Service注解 

1.  
   @Service
2.  
   public class DeptServiceImpl implements DeptService{
3.  
   @Autowired
4.  
   DeptMapper deptMapper;
5.  
    
6.  
   @Override
7.  
   public Dept queryByDeptNo(Long deptno) {
8.  
   return deptMapper.queryByDeptNo(deptno);
9.  
   }
10.  
     
11.  
    @Override
12.  
    public List<Dept> queryAll() {
13.  
    return deptMapper.queryAll();
14.  
    }
15.  
     
16.  
    @Override
17.  
    public boolean addDept(Dept dept) {
18.  
    return deptMapper.addDept(dept);
19.  
    }
20.  
     
21.  
    @Override
22.  
    public boolean updateDept(Dept dept) {
23.  
    return deptMapper.updateDept(dept);
24.  
    }
25.  
     
26.  
    @Override
27.  
    public boolean deleteDept(Long deptno) {
28.  
    return deptMapper.deleteDept(deptno);
29.  
    }
30.  
    }

5.编写Controller层 

GetMapping用于查询、PostMapping用于添加、PutMapping用于修改、DeleteMapping用于删除

RestController为Controller与ResponseBody的合成注解（标记Controller组件及使请求方法返回Json数据）

1.  
   @RestController
2.  
   @RequestMapping("/Dept")
3.  
   public class DeptController {
4.  
   @Autowired//自动写入实现类
5.  
   DeptServiceImpl deptServiceImpl;
6.  
    
7.  
   @GetMapping("/{deptno}")
8.  
   public Dept queryByDeptNo(@PathVariable("deptno") Long deptno) {
9.  
   return deptServiceImpl.queryByDeptNo(deptno);
10.  
    }
11.  
     
12.  
    @GetMapping
13.  
    public List<Dept> queryAll() {
14.  
    return deptServiceImpl.queryAll();
15.  
    }
16.  
     
17.  
    @PostMapping()
18.  
    public boolean addDept(Dept dept) {
19.  
    return deptServiceImpl.addDept(dept);
20.  
    }
21.  
     
22.  
    @PutMapping
23.  
    public boolean update(Dept dept){
24.  
    return deptServiceImpl.updateDept(dept);
25.  
    }
26.  
     
27.  
    @DeleteMapping("/{deptno}")
28.  
    public boolean deleteDept(@PathVariable("deptno") Long deptno){
29.  
    return deptServiceImpl.deleteDept(deptno);
30.  
    }
31.  
     
32.  
    }

6.编写Mapper文件

1.  
   <?xml version="1.0" encoding="UTF-8" ?>
2.  
   <!DOCTYPE mapper
3.  
   PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
4.  
   "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
5.  
   <mapper namespace="cn.alan.springcloud.DAO.DeptMapper">
6.  
   <select id="queryByDeptNo" parameterType="Long" resultType="Dept">
7.  
   select *
8.  
   from mybatis.dept
9.  
   where deptno = #{deptno};
10.  
    </select>
11.  
     
12.  
    <select id="queryAll" resultType="Dept">
13.  
    select *
14.  
    from mybatis.dept;
15.  
    </select>
16.  
     
17.  
    <insert id="addDept" parameterType="Dept">
18.  
    insert into mybatis.dept (dname, db_source)
19.  
    VALUES (#{dname}, DATABASE());
20.  
    </insert>
21.  
     
22.  
    <update id="updateDept" parameterType="Dept">
23.  
    update mybatis.dept
24.  
    set dname = #{dname},
25.  
    db_source = DATABASE()
26.  
    where deptno = #{deptno};
27.  
    </update>
28.  
     
29.  
    <delete id="deleteDept" parameterType="Long">
30.  
    delete
31.  
    from mybatis.dept
32.  
    where deptno = #{deptno}
33.  
    </delete>
34.  
    </mapper>

07.配置yml文件

1.  
   server:
2.  
   port: 8001
3.  
    
4.  
   spring:
5.  
   application:
6.  
   name: springcloud-provider-dept
7.  
   datasource:
8.  
   driver-class-name: com.mysql.cj.jdbc.Driver
9.  
   url: jdbc:mysql://localhost:3306/mybatis?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
10.  
    username: 数据库用户名
11.  
    password: 数据库密码
12.  
     
13.  
    mybatis:
14.  
    mapper-locations: classpath:mybatis/mapper/*.xml #mapper文件路径
15.  
    type-aliases-package: cn.alan.springcloud.POJO #实体类别名（使得mapper文件中不用写全限定名）

二.创建服务消费者Consumer

基于Feign

1.导入依赖

1.  
   <!--实体类所在模块-->
2.  
   <dependency>
3.  
   <groupId>org.example</groupId>
4.  
   <artifactId>SpringCloud-API</artifactId>
5.  
   <version>1.0-SNAPSHOT</version>
6.  
   </dependency>
7.  
   <!--web依赖-->
8.  
   <dependency>
9.  
   <groupId>org.springframework.boot</groupId>
10.  
    <artifactId>spring-boot-starter-web</artifactId>
11.  
    <version>2.6.7</version>
12.  
    </dependency>
13.  
    <!--热部署-->
14.  
    <dependency>
15.  
    <groupId>org.springframework.boot</groupId>
16.  
    <artifactId>spring-boot-devtools</artifactId>
17.  
    <version>2.6.7</version>
18.  
    </dependency>
19.  
    <!--feign依赖-->
20.  
    <dependency>
21.  
    <groupId>org.springframework.cloud</groupId>
22.  
    <artifactId>spring-cloud-starter-openfeign</artifactId>
23.  
    <version>3.1.2</version>
24.  
    </dependency>

2.编写主启动类

注：记得添加@EnableFeignClients注解用于开启Feign

1.  
   @SpringBootApplication
2.  
   @EnableFeignClients//开启Feign
3.  
   public class DpetConsumer_80_Feign {
4.  
   public static void main(String[] args) {
5.  
   SpringApplication.run(DpetConsumer_80_Feign.class);
6.  
   }
7.  
   }

3.编写FeignClient

注：记得添加@Component注解（将FeignDeptClient类交给Spring管理）与@FeignClient注解

注：若使用了eureka注册中心，则name属性填写服务名，url无需填写

1.  
   @Component
2.  
   @FeignClient(name = "FeignWithoutEureka",url = "http://localhost:8001/Dept/")
3.  
   public interface FeignDeptClient {
4.  
   @GetMapping("/{deptno}")
5.  
   Dept queryByDeptNo(@PathVariable("deptno") Long deptno);
6.  
    
7.  
   @GetMapping
8.  
   List<Dept> queryAll();
9.  
    
10.  
    @PostMapping
11.  
    boolean addDept(Dept dept);
12.  
     
13.  
    @PutMapping
14.  
    boolean updateDept(Dept dept);
15.  
     
16.  
    @DeleteMapping("/{deptno}")
17.  
    boolean deleteDept(@PathVariable("deptno") Long deptno);
18.  
    }

4.编写Controller层

1.  
   @RestController
2.  
   @RequestMapping("/Consumer")
3.  
   public class DeptConsumerController {
4.  
   @Autowired//自动写入FeignClient（FeignDeptClient类）
5.  
   FeignDeptClient feignDeptClient;
6.  
    
7.  
   @GetMapping("/{deptno}")
8.  
   Dept queryByDeptNo(@PathVariable("deptno") Long deptno) {
9.  
   return feignDeptClient.queryByDeptNo(deptno);
10.  
    }
11.  
     
12.  
    @GetMapping
13.  
    List<Dept> queryAll(){
14.  
    return feignDeptClient.queryAll();
15.  
    }
16.  
     
17.  
    @PostMapping()
18.  
    public boolean addDept(Dept dept) {
19.  
    return feignDeptClient.addDept(dept);
20.  
    }
21.  
     
22.  
    @PutMapping
23.  
    public boolean update(Dept dept){
24.  
    return feignDeptClient.updateDept(dept);
25.  
    }
26.  
     
27.  
    @DeleteMapping("/{deptno}")
28.  
    public boolean deleteDept(@PathVariable("deptno") Long deptno){
29.  
    return feignDeptClient.deleteDept(deptno);
30.  
    }
31.  
    }

5.配置yml文件

1.  
   server:
2.  
   port: 80

基于RestTemplate

1.添加依赖

1.  
   <!--实体类所在模块-->
2.  
   <dependency>
3.  
   <groupId>org.example</groupId>
4.  
   <artifactId>SpringCloud-API</artifactId>
5.  
   <version>1.0-SNAPSHOT</version>
6.  
   </dependency>
7.  
   <!--web依赖-->
8.  
   <dependency>
9.  
   <groupId>org.springframework.boot</groupId>
10.  
    <artifactId>spring-boot-starter-web</artifactId>
11.  
    <version>2.6.7</version>
12.  
    </dependency>
13.  
    <!--热部署依赖-->
14.  
    <dependency>
15.  
    <groupId>org.springframework.boot</groupId>
16.  
    <artifactId>spring-boot-devtools</artifactId>
17.  
    <version>2.6.7</version>
18.  
    </dependency>

2.编写主启动类

注：记得添加@SpringBootApplication注解

1.  
   @SpringBootApplication
2.  
   public class DeptConsumer_80 {
3.  
   public static void main(String[] args) {
4.  
   SpringApplication.run(DeptConsumer_80.class,args);
5.  
   }
6.  
   }

3.编写RestTemplate配置类

注：记得在类上方添加@Configuration注解，方法上方添加@Bean注解

1.  
   @Configuration
2.  
   public class RestTemplateConfig {
3.  
   @Bean
4.  
   public RestTemplate restTemplate() {
5.  
   return new RestTemplate();
6.  
   }
7.  
   }

4.编写Controller层

1.  
   @RestController//Controller和ResponseBody融合注解 向spring标注当前类为controller
2.  
   @RequestMapping("/Consumer")
3.  
   public class DeptConsumerController {
4.  
   @Autowired
5.  
   RestTemplate restTemplate;//基于http通信 通过RestTemplate调用provider接口
6.  
    
7.  
   //不使用eureka时 使用服务端口进行调用
8.  
   private static final String REST_URL_PREFIX = "http://localhost:8001/Dept/";
9.  
    
10.  
    @GetMapping("/{deptno}")
11.  
    public Dept queryByDeptNo(@PathVariable("deptno") Long deptno) {
12.  
    //参数：url 返回值类型
13.  
    return restTemplate.getForObject(REST_URL_PREFIX deptno, Dept.class);
14.  
    }
15.  
     
16.  
    @GetMapping
17.  
    public List<Dept> queryAll() {
18.  
    return restTemplate.getForObject(REST_URL_PREFIX, List.class);//注意此处类型为List 区别于mapper.xml中填写List的泛型的类型
19.  
    }
20.  
     
21.  
    @PostMapping
22.  
    public boolean addDept(Dept dept) {
23.  
    //参数：url 传递的参数 返回值类型
24.  
    return restTemplate.postForObject(REST_URL_PREFIX, dept, Boolean.class);
25.  
    }

5.配置yml文件

1.  
   server:
2.  
   port: 80

运行效果 

        运行Provider与Consumer的主启动类，借助swagger、postman等工具，选择请求发送的方式即可查看运行效果

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