一、引言
什么是Feign
以JAVA注解的方式定义的远程调用API接口,最终转换成HTTP的请求形式。然后将HTTP的请求的响应结果,解析成JAVA Bean,返回给调用方,实现远程接口调用。
对RPC远程过程调用的一种实现,通过注解可以很方便的去进行RPC调用,减少配置。
二、Feign调用实例
我们需要创建2个工程:order-server、gds-server,然后分别在其中定义出controller来模拟订单系统调用商品系统的业务流程。
gds-server
pom.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
4 <modelVersion>4.0.0</modelVersion>
5 <groupId>com.zhbf</groupId>
6 <artifactId>gds-server</artifactId>
7 <version>0.0.1-SNAPSHOT</version>
8 <name>gds-server</name>
9 <description>商品服务【有梦想的肥宅】</description>
10
11 <parent>
12 <groupId>org.springframework.boot</groupId>
13 <artifactId>spring-boot-starter-parent</artifactId>
14 <version>1.5.6.RELEASE</version>
15 <relativePath/>
16 </parent>
17
18 <properties>
19 <java.version>1.8</java.version>
20 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
21 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
22 <spring-boot.version>1.5.6.RELEASE</spring-boot.version><!--Spring Boot版本-->
23 <spring-cloud.version>1.4.6.RELEASE</spring-cloud.version><!--Spring Cloud版本-->
24 </properties>
25
26 <dependencyManagement>
27 <dependencies>
28 <!--指定下载源和使用Spring Boot的版本-->
29 <dependency>
30 <groupId>org.springframework.boot</groupId>
31 <artifactId>spring-boot-dependencies</artifactId>
32 <version>${spring-boot.version}</version>
33 <type>pom</type>
34 <scope>import</scope>
35 </dependency>
36 <!--指定下载源和使用Spring Cloud的版本-->
37 <dependency>
38 <groupId>org.springframework.cloud</groupId>
39 <artifactId>spring-cloud-dependencies</artifactId>
40 <version>Edgware.SR5</version>
41 <type>pom</type>
42 <scope>import</scope>
43 </dependency>
44 </dependencies>
45 </dependencyManagement>
46
47
48 <dependencies>
49 <!--引入Spring Boot依赖-->
50 <dependency>
51 <groupId>org.springframework.boot</groupId>
52 <artifactId>spring-boot-starter</artifactId>
53 </dependency>
54 <!--引入lombok-->
55 <dependency>
56 <groupId>org.projectlombok</groupId>
57 <artifactId>lombok</artifactId>
58 <optional>true</optional>
59 </dependency>
60 <!--引入Spring Cloud的Eureka依赖-->
61 <dependency>
62 <groupId>org.springframework.cloud</groupId>
63 <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
64 <version>${spring-cloud.version}</version>
65 </dependency>
66 <!--引入fastjson依赖-->
67 <dependency>
68 <groupId>com.alibaba</groupId>
69 <artifactId>fastjson</artifactId>
70 <version>1.2.76</version>
71 </dependency>
72 <!--服务调用-->
73 <dependency>
74 <groupId>org.springframework.cloud</groupId>
75 <artifactId>spring-cloud-starter-openfeign</artifactId>
76 </dependency>
77 </dependencies>
78
79 </project>
View Code
controller
/**
* @author 有梦想的肥宅
* @date 2021/9/6
*/
@RestController
public class GdsController {
@RequestMapping("/getGdsInfo")
public Map getGdsInfo(@RequestParam String gdsId) {
Map gdsInfo = new HashMap();
gdsInfo.put("gdsId", gdsId);
gdsInfo.put("gdsName", "测试商品名称");
gdsInfo.put("shopName", "【有梦想的肥宅】小店");
return gdsInfo;
}
}
application.yml
#应用名称
spring:
application:
name: GDS-SERVER
#服务端口
server:
port: 9092
#Eureka配置
eureka:
client:
service-url:
defaultZone: http://${eureka.instance.hostname}:9090/eureka
instance:
hostname: 127.0.0.1
GdsServerApplication.java【启动类】
@SpringBootApplication
@EnableDiscoveryClient //服务注册发现
@EnableFeignClients //服务调用
public class GdsServerApplication {
public static void main(String[] args) {
SpringApplication.run(GdsServerApplication.class, args);
}
}
order-server
pom.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
4 <modelVersion>4.0.0</modelVersion>
5 <groupId>com.zhbf</groupId>
6 <artifactId>order-server</artifactId>
7 <version>0.0.1-SNAPSHOT</version>
8 <name>order-server</name>
9 <description>订单服务【有梦想的肥宅】</description>
10
11 <parent>
12 <groupId>org.springframework.boot</groupId>
13 <artifactId>spring-boot-starter-parent</artifactId>
14 <version>1.5.6.RELEASE</version>
15 <relativePath/>
16 </parent>
17
18 <properties>
19 <java.version>1.8</java.version>
20 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
21 <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
22 <spring-boot.version>1.5.6.RELEASE</spring-boot.version><!--Spring Boot版本-->
23 <spring-cloud.version>1.4.6.RELEASE</spring-cloud.version><!--Spring Cloud版本-->
24 </properties>
25
26 <dependencyManagement>
27 <dependencies>
28 <!--指定下载源和使用Spring Boot的版本-->
29 <dependency>
30 <groupId>org.springframework.boot</groupId>
31 <artifactId>spring-boot-dependencies</artifactId>
32 <version>${spring-boot.version}</version>
33 <type>pom</type>
34 <scope>import</scope>
35 </dependency>
36 <!--指定下载源和使用Spring Cloud的版本-->
37 <dependency>
38 <groupId>org.springframework.cloud</groupId>
39 <artifactId>spring-cloud-dependencies</artifactId>
40 <version>Edgware.SR5</version>
41 <type>pom</type>
42 <scope>import</scope>
43 </dependency>
44 </dependencies>
45 </dependencyManagement>
46
47
48 <dependencies>
49 <!--引入Spring Boot依赖-->
50 <dependency>
51 <groupId>org.springframework.boot</groupId>
52 <artifactId>spring-boot-starter</artifactId>
53 </dependency>
54 <!--引入lombok-->
55 <dependency>
56 <groupId>org.projectlombok</groupId>
57 <artifactId>lombok</artifactId>
58 <optional>true</optional>
59 </dependency>
60 <!--引入Spring Cloud的Eureka依赖-->
61 <dependency>
62 <groupId>org.springframework.cloud</groupId>
63 <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
64 <version>${spring-cloud.version}</version>
65 </dependency>
66 <!--引入fastjson依赖-->
67 <dependency>
68 <groupId>com.alibaba</groupId>
69 <artifactId>fastjson</artifactId>
70 <version>1.2.76</version>
71 </dependency>
72 <!--服务调用-->
73 <dependency>
74 <groupId>org.springframework.cloud</groupId>
75 <artifactId>spring-cloud-starter-openfeign</artifactId>
76 </dependency>
77 </dependencies>
78 </project>
View Code
调用商品服务的fegin接口
/**
* 调用商品服务的fegin接口
*
* @author 有梦想的肥宅
*/
@FeignClient(value = "GDS-SERVER", path = "/")//这里表示使用feign去调用应用名为GDS-SERVER的内部服务
public interface OutGdsApi {
/**
* 查询商品信息
*/
@RequestMapping("/getGdsInfo")//表示通过feign发送http请求到GDS-SERVER的应用,地址映射为"/getGdsInfo"
Map getGdsInfo(@RequestParam("gdsId") String gdsId);
}
controller
/**
* @author 有梦想的肥宅
* @date 2021/9/6
*/
@RestController
public class OrderController {
@Autowired
private OutGdsApi outGdsApi;//自动注入调用商品服务的fegin接口
@RequestMapping("/showOrderInfo")
public String showOrderInfo() {
Map orderInfo = new HashMap();
orderInfo.put("orderId", 1);
orderInfo.put("gdsInfo", outGdsApi.getGdsInfo("1"));
return JSON.toJSONString(orderInfo);
}
}
application.yml
#应用名称
spring:
application:
name: OREDER-SERVER
#服务端口
server:
port: 9091
#Eureka配置
eureka:
client:
service-url:
defaultZone: http://${eureka.instance.hostname}:9090/eureka
instance:
hostname: 127.0.0.1
OrderServerApplication.java【启动类】
@SpringBootApplication
@EnableDiscoveryClient //服务注册发现
@EnableFeignClients //服务调用
public class OrderServerApplication {
public static void main(String[] args) {
SpringApplication.run(OrderServerApplication.class, args);
}
}
分别启动gds-server、order-server工程,查看效果