spring-cloud-feign实战笔记

feign 配置

1. 针对单个feign接口进行配置

   feign:client:config:# feignName 注意这里与contextId一致，不能写成name（FeignClientFactoryBean#configureFeign）# 不能写成 client-b (微服务名称)，否则不生效helloFeignClient: # contextIdconnectTimeout: 50000 # 连接超时时间readTimeout: 50000 # 读超时时间loggerLevel: full #配置Feign的日志级别#default:# 其他默认配置
   

2. feign 全局默认配置

   feign:client:config:default:connectTimeout: 50000 # 连接超时时间readTimeout: 50000 # 读超时时间loggerLevel: full #配置Feign的日志级别
   

3. feign开启gzip支持

   feign:compression:request:enabled: truemime-types: "text/xml, application/xml, application/json"min-request-size: 2048response:enabled: true # 配置相应GZIP压缩
   

开启gzip支持后接口调用处理（方式一）

1. feign接口使用ResponseEntity<byte []>接收数据

   @FeignClient(contextId = "testFeignClient", name = "client-a")
   public interface TestFeignClient {@GetMapping(value = "/userInfo")ResponseEntity<byte []> userInfoCompress(@RequestParam("username") String username, @RequestParam("address") String address) ;
   }
   

2. 编写单元测试（注意需要对byte[] 数组使用Gzip解压）

   @Slf4j
   public class TestFeignClientTest extends BaseJunitTest {@Autowiredprivate TestFeignClient testFeignClient ;@Testpublic void userInfoCompress() throws IOException {String username = "张三" ;String address = "北京" ;ResponseEntity<byte[]> responseEntity = testFeignClient.userInfoCompress(username, address);byte[] compressed = responseEntity.getBody();String decompressValue = GzipUtils.decompress(compressed);log.info("value : {}", decompressValue);}
   }
   

3. 编写gzip解压缩工具类

   public final class GzipUtils {public static String decompress(byte [] compressed) throws IOException {final StringBuilder output = new StringBuilder() ;try(GZIPInputStream gis = new GZIPInputStream(new ByteArrayInputStream(compressed));BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(gis, StandardCharsets.UTF_8))){String line ;while ((line = bufferedReader.readLine()) != null){output.append(line) ;}return output.toString() ;}}
   }
   

开启gzip支持后接口调用处理（方式二）

1. 编写Decoder （内部使用方式一的Gzip解压缩工具类GzipUtils）

   public class FeignResponseDecoder implements Decoder {private final Decoder delegate;public FeignResponseDecoder(Decoder delegate) {Objects.requireNonNull(delegate, "Decoder must not be null. ");this.delegate = delegate;}@Overridepublic Object decode(Response response, Type type) throws IOException {Collection<String> values = response.headers().get(HttpEncoding.CONTENT_ENCODING_HEADER);if (Objects.nonNull(values) && !values.isEmpty() && values.contains(HttpEncoding.GZIP_ENCODING)) {byte[] compressed = Util.toByteArray(response.body().asInputStream());if ((compressed == null) || (compressed.length == 0)) {return delegate.decode(response, type);}//decompression part//after decompress we are delegating the decompressed response to default//decoderif (isCompressed(compressed)) {String decompressValue = GzipUtils.decompress(compressed);Response decompressedResponse = response.toBuilder().body(decompressValue.getBytes()).build();return delegate.decode(decompressedResponse, type);} else {return delegate.decode(response, type);}} else {return delegate.decode(response, type);}}private static boolean isCompressed(final byte[] compressed) {return (compressed[0] == (byte) (GZIPInputStream.GZIP_MAGIC)) && (compressed[1] == (byte) (GZIPInputStream.GZIP_MAGIC >> 8));}
   }
   

2. 将Decoder加入到Spring容器管理

   @Configuration
   public class AppConfig{@Beanpublic Decoder GZIPResponseDecoder(ObjectFactory<HttpMessageConverters> messageConverters) {Decoder decoder = new FeignResponseDecoder(new SpringDecoder(messageConverters));return decoder;}
   }
   

3. feign接口使用普通java对象接收数据

   @FeignClient(contextId = "testFeignClient", name = "client-a")
   public interface TestFeignClient {@GetMapping("/userInfo")UserInfoVO userInfo(@RequestParam("username") String username, @RequestParam("address") String address) ;
   }
   

4. 编写单元测试

   @Slf4j
   public class TestFeignClientTest extends BaseJunitTest {@Autowiredprivate TestFeignClient testFeignClient ;@Testpublic void userInfo(){String username = "张三" ;String address = "北京" ;UserInfoVO userInfo = testFeignClient.userInfo(username, address);log.info("user info : {}", userInfo);}
   }
   

其他知识点补充

1. SpringBoot服务提供者开启gizp压缩

   server:port: 7070compression:enabled: true