目录
no suitable HttpMessageConverter found for response type
本章内容讲解重点目标以及面向用户
| 本章目标 | 了解feign的原理 掌握feign的使用 学会feign多种header的设置方式 学会feign日志控制 了解feign高阶配置项 其他开发注意事项 |
| 面向用户 | 初、中、高阶的研发同学 |
一、SpringBoot快速整合Feign
1.添加Pom依赖
<properties>
<spring-cloud-feign.version>3.1.3</spring-cloud-feign.version>
</properties>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.10</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
<version>${spring-cloud-feign.version}</version>
</dependency>
</dependencies>2.启动类添加注解
@EnableFeignClients3.引用Feign服务
@RestController
@RequestMapping("/stock")
public class StockController {
@Autowired
private LocalFeignService service;
@GetMapping("/get")
public String get(){
service.add("10");
return "Hello world";
}
}二、为请求添加Header的3种方式
1.添加固定header
@RestController
public class HomeController {
@Resource
private FeignClientService feignClientService;
@RequestMapping(value = "/add")
public String add(@RequestBody FeignReq req) {
return "ok";
}
@RequestMapping("/test-add")
public Object testAdd() {
FeignReq req = new FeignReq();
req.setId(System.currentTimeMillis());
return feignClientService.add(req);
}
}在@PostMapping注解的headers参数中添加固定的header值，也包括一些从配置文件读取的配置项作为header值
@Component
@FeignClient(name = "feignClientService", url = "http://localhost:8081")
public interface FeignClientService {
@PostMapping(value = "/add", headers = {"Authorization=myFeignSignToken", "Content-Type=text/plain", "App=${my.name}"})
public String add(@RequestBody FeignReq req);
}浏览器访问：http://localhost:8081/test-add
2.通过接口签名添加header
@RestController
public class HomeController {
@Resource
private FeignClientService feignClientService;
@PostMapping(value = "/query")
public String query(@RequestParam("queryName") String queryName) {
return queryName + "ok";
}
@RequestMapping("/test-query")
public Object testQuery() {
Map<String, String> map = new HashMap<>();
map.put("token", "ikong_token"+System.currentTimeMillis());
return feignClientService.query("ikong", map);
}
}重点是在Map类型的headers，这里通过接口签名的@RequestHeader注解将Map对象转化成请求header
@Component
@FeignClient(name = "feignClientService", url = "http://localhost:8081", configuration = TestRequestInterceptor.class)
public interface FeignClientService {
@PostMapping(value = "/query")
public String query(@RequestParam("queryName") String queryName, @RequestHeader Map<String, String> headers);
}浏览器访问：http://localhost:8081/test-query
3.动态添加header
@RestController
public class HomeController {
@Resource
private FeignClientService feignClientService;
@RequestMapping("/search")
public Object search(@RequestBody FeignReq req) {
return "ok";
}
@RequestMapping("/test-search")
public Object testSearch() {
FeignReq req = new FeignReq();
req.setId(System.currentTimeMillis());
return feignClientService.search(req);
}
}
@Component
@FeignClient(name = "feignClientService", url = "http://localhost:8081", configuration = TestRequestInterceptor.class)
public interface FeignClientService {
@PostMapping("/search")
public String search(@RequestBody FeignReq req);
}通过FeignClient注解注入configuration = TestRequestInterceptor.class，在TestRequestInterceptor实现header动态添加能力
public class TestRequestInterceptor implements RequestInterceptor {
@Override
public void apply(RequestTemplate template) {
template.header(HttpHeaders.AUTHORIZATION, createApiSign());
}
/**
* 创建接口签名
*
* @return
*/
private String createApiSign() {
return UUID.randomUUID().toString();
}
}浏览器访问：http://localhost:8081/test-search
三、为请求添加超时配置
1.默认超时时间
connectiontimeout : 10s，readtimeout : 60s
public static class Options {
private final int connectTimeoutMillis;
private final int readTimeoutMillis;
public Options(int connectTimeoutMillis, int readTimeoutMillis) {
this.connectTimeoutMillis = connectTimeoutMillis;
this.readTimeoutMillis = readTimeoutMillis;
}
public Options() {
this(10 * 1000, 60 * 1000);
}
/**
* Defaults to 10 seconds. {@code 0} implies no timeout.
*
* @see java.net.HttpURLConnection#getConnectTimeout()
*/
public int connectTimeoutMillis() {
return connectTimeoutMillis;
}
/**
* Defaults to 60 seconds. {@code 0} implies no timeout.
*
* @see java.net.HttpURLConnection#getReadTimeout()
*/
public int readTimeoutMillis() {
return readTimeoutMillis;
}
}3.超时异常
exception:feign.RetryableException: connect timed out executing POST http://xxx.ik.com/your/api4.全局超时配置
feign.client.config.default.connectTimeout=5000
feign.client.config.default.readTimeout=50005.为单个服务设置超时配置
feign.client.config.yourService.connectTimeout=5
feign.client.config.yourService.readTimeout=5四、为请求配置客户端负载均衡模式
五、Feign日志
1.日志级别
2.日志配置类
@Configuration
public class OpenFeignLogConfig {
@Bean
Logger.Level feignLoggerLevel(){
return Logger.Level.FULL;
}
}3.配置文件
logging:
level:
*[feign日志以什么级别监控哪个接口]:
com.ik.ikong.service.FeignClientService: debug六、高阶配置
七、Feign与Springboot版本
版本对照关系如下，详情也可以点击这里的链接在官网查看最新版本兼容关系
八、技术问题
在调用接口时候idea报错
解决过程
1.放开日志
@Configuration
public class FeignConfiguration {
@Bean
public feign.Logger logger() {
return new Slf4jLogger();
}
@Bean
public Logger.Level level() {
return Logger.Level.FULL;
}
}logging:
level:
feign.Logger: debug日志详细
从放开的日志来看，接口返回的head里：content-type: text/html; charset=UTF-8
虽然我在接口签名上增加了produces、consumes
@PostMapping(value = "/xxxxx/your/api", produces = "application/json;charset=utf-8", consumes = "application/json;charset=utf-8")可以看到毫无效果，仍旧异常：no suitable HttpMessageConverter found for response type
猜想原生的http返回值只对application/json类型做了泛型的反序列化处理，是对接口返回的content-type: text/html;并不能进行json反序列化处理，遂增加该类型的json反序列化处理；
@Bean
public HttpMessageConverters customConverters() {
MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
mappingJackson2HttpMessageConverter.setSupportedMediaTypes(Arrays.asList(MediaType.TEXT_HTML,MediaType.APPLICATION_JSON));
return new HttpMessageConverters(false, Arrays.asList(mappingJackson2HttpMessageConverter, new StringHttpMessageConverter()));
}重点在mappingJackson2HttpMessageConverter.setSupportedMediaTypes(Arrays.asList(MediaType.TEXT_HTML,MediaType.APPLICATION_JSON));
最后成功完成增加content-type: text/html的json反序列化；
参考：Spring Cloud
Feign实现服务间的Http调用。_feign http调用_半命i的博客-CSDN博客
