springboot 整合feign
Spring Cloud为Feign添加了Spring MVC的注解支持,并整合了Ribbon和Eureka来为使用Feign时提供负载均衡。
使用Feign
1. 添加依赖
<dependencies>
<!--openfein的依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
</dependencies>
2. 启用Feign
启用类上添加注解@EnableFeignClients
客户端允许开启使用Feign调用,扫描@FeignClient
标注的FeignClient接口
@SpringBootApplication
@EnableFeignClients
@EnableWeb
public class FeignApplication {
public static void main(String[] args) {
SpringApplication.run(FeignApplication.class,args);
}
}
3. 编写FeignClient接口
@FeignClient(
name = "demo-service",
url = "http://localhost:8080/feign/server/",
configuration = FeignInterceptor.class,
fallback = TestService.DefaultFallback.class
)
public interface TestService {
@RequestMapping(value = "/getError/{id}", method = RequestMethod.GET)
public String getError(@RequestParam("id") Integer id);
@RequestMapping(value = "/get1", method = RequestMethod.GET)
public String get1();
@RequestMapping(value = "/get2/{param}", method = RequestMethod.GET)
public String get2(@RequestParam("param") String param);
@RequestMapping(value = "/post1", method = RequestMethod.POST)
public FeignDemo post1(@RequestBody FeignDemo demo);
4. 对应的服务端
@RestController
@RequestMapping("/feign/server")
public class FeignServerController {
@GetMapping("/get1")
public String get1() {
return "get1";
}
@GetMapping("/get2/{para}")
public String get2(@PathVariable("para") String para){
return para;
}
@PostMapping("/post1")
public FeignDemo post1(@RequestBody FeignDemo demo) {
return demo;
}
@Component
public class DefaultFallback implements TestService {
@Override
public String getError(@RequestParam("id") Integer id){
return "";
}
@Override
public String get1() {
return null;
}
@Override
public String get2(String param) {
return null;
}
@Override
public FeignDemo post1(FeignDemo demo) {
return null;
}
}
}
public class FeignDemo {
private String name;
private Integer age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "FeignDemo{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
5. 调用FeignClient
@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(classes = {FeignApplication.class},webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
@ActiveProfiles("dev,feign")
public class FeignClientTest {
@Autowired
private TestService testService;
@Test
public void testFallback(){
testService.getError(1);
}
@Test
public void testGet1(){
System.out.println(testService.get1());
System.out.println(testService.get2("abc"));
System.out.printf("..");
FeignDemo feignDemo = new FeignDemo();
feignDemo.setName("name");
feignDemo.setAge(1);
System.out.println(testService.post1(feignDemo));
}
}
使用Apache的HTTP Client
使用Apache的HTTP Client替换Feign原生httpclient
1. 添加依赖
<!--httpclient的依赖,因为选择了使用httpclient-->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
</dependency>
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-httpclient</artifactId>
<version>10.4.0</version>
</dependency>
2. 启用
配置中添加如下信息,表示启用httpclient。
feign:
httpclient:
enabled: true
Feign中使用OkHttp
1. 添加依赖
在Feign中使用OkHttp作为网络请求框架,则只需要在pom文件中加上feign-okhttp的依赖,代码如下:
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-okhttp</artifactId>
<version>10.2.0</version>
</dependency
启用配置
feign:
okhttp:
enabled: true
修改日志级别
在发送和接收请求的时候,将日志的输出定义了四个等级:
级别 | 说明 |
---|---|
NONE | 不做任何记录 |
BASIC | 仅记录请求方法和URL以及响应状态代码和执行时间 |
HEADERS | 记录基本信息以及请求和响应标头 |
FULL | 记录请求和响应的标题,正文和元数据 |
1. 通过配置
接口的全路径名
logging:
level:
com.zto.titans.test.feign.service.TestService : DEBUG
2. 通过配置类
@Configuration
public class FooConfiguration {
@Bean
Logger.Level feignLoggerLevel() {
return Logger.Level.FULL;
}
}
数据压缩
feign:
compression:
request:
enabled: true
response:
enabled: true
配置以及配置覆盖
1. 自定义配置类,指定配置
public class TestConfiguration {
@Bean
Logger.Level feignLoggerLevel() {
return Logger.Level.FULL;
}
}
将TestConfiguration
指定到configuration中。
@FeignClient(
name = "test-service",
configuration = {FeignInterceptor2.class,TestConfiguration.class}
)
2. 配置文件中 default全局配置
feign.client.config.default.xxx ,通过这个default创建全局的配置属性。
feign:
client:
config:
default:
connectTimeout: 5000
readTimeout: 5000
loggerLevel: basic
3. 配置文件中专属配置
feign.client.config.feignName.xxx , 按名字指定FeignClient的配置。
feign:
client:
config:
feignName:
connectTimeout: 5000
readTimeout: 5000
loggerLevel: full
errorDecoder: com.example.SimpleErrorDecoder
retryer: com.example.SimpleRetryer
requestInterceptors:
- com.example.FooRequestInterceptor
- com.example.BarRequestInterceptor
decode404: false
encoder: com.example.SimpleEncoder
decoder: com.example.SimpleDecoder
3. 配置的覆盖与追加
org.springframework.cloud.openfeign.FeignClientFactoryBean#configureFeign
中可以确认几个配置的优先级:
- 自定义配置类,指定配置
- 配置文件中 default全局配置
- 配置文件中专属配置
configureUsingConfiguration(context, builder); // 1
configureUsingProperties(properties.getConfig().get(properties.getDefaultConfig()),builder); //2
configureUsingProperties(properties.getConfig().get(this.contextId),builder);//3
1. 覆盖的原则
3 -覆盖-> 2 -覆盖-> 1
2. 追加的原则
requestInterceptors不是覆盖的模式,而是追加,从requestInterceptors的执行顺序的优先级看是:
1 > 2 > 3
注意:RequestInterceptor 的实现类,如果使用@Component注解,那么都会被识别到,并在1中添加,若 还在配置中指定了,在2,和3中会继续在requestInterceptors列表中追加,产生重复。
拦截器
RequestInterceptor 就是拦截器 可以在发送前做一些处理,比如统一添加header信息。
其添加的一些规则,上配置追加里有提及
1. 自定义三个RequestInterceptor
class FeignInterceptor implements RequestInterceptor {
@Override
public void apply(RequestTemplate requestTemplate) {
requestTemplate.header("user", "myuser1");
requestTemplate.header("password", "mypassword");
}
}
class FeignInterceptor1 implements RequestInterceptor {
@Override
public void apply(RequestTemplate requestTemplate) {
requestTemplate.header("user1", "myuser1");
requestTemplate.header("password1", "mypassword1");
}
}
class FeignInterceptor2 implements RequestInterceptor {
@Override
public void apply(RequestTemplate requestTemplate) {
requestTemplate.header("user2", "myuser2");
requestTemplate.header("password2", "mypassword2");
}
}
2. @FeignClient中指定一个
@FeignClient(
name = "test-service",
url = "http://localhost:8080/feign/server/",
configuration = {FeignInterceptor.class,TestConfiguration.class},
fallback = TestService.DefaultFallback.class
)
3. 配置中指定2个
default 指定了一个,test-service里指定一个
feign:
httpclient:
enabled: true
okhttp:
enabled: true
client:
config:
default:
connectTimeout: 5000
readTimeout: 5000
#loggerLevel: none
requestInterceptors:
- com.zto.titans.test.feign.service.FeignInterceptor1
test-service:
#loggerLevel: basic
requestInterceptors:
- com.zto.titans.test.feign.service.FeignInterceptor2
logging:
level:
com.zto.titans.test.feign.service.TestService : DEBUG
根据配置的的追加逻辑,最终执行的顺序是:
1:FeignInterceptor
2:FeignInterceptor1
3:FeignInterceptor2
cat 埋点:
断路器
Feign使用Hystrix
作者:rock_fish
链接:https://www.jianshu.com/p/49accf2167b2
来源:简书
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