OpenFeign源码深度解析:注解如何一步步转化为HTTP请求

• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 29
• 30
• 31
• 32

@OverridepublicObject getObject()throwsException{return getTarget();}<T> T getTarget() {FeignContext context = applicationContext.getBean(FeignContext.class);Feign.Builder builder = feign(context);if(!StringUtils.hasText(url)){if(name ==null){ name ="";}String url = name.startsWith("http")? name :"http://"+ name;return(T) loadBalance(builder, context,newHardCodedTarget<>(type, name, url));}if(StringUtils.hasText(url)&&!url.startsWith("http")){ url ="http://"+ url;}String url =this.url + cleanPath();Client client = getOptional(context,Client.class);if(client !=null){if(client instanceofLoadBalancerFeignClient){// not load balancing because we have a url,// but ribbon is on the classpath, so unwrap client =((LoadBalancerFeignClient) client).getDelegate();} builder.client(client);}Targeter targeter =get(context,Targeter.class);return(T) targeter.target(this, builder, context,newHardCodedTarget<>(type, name, url));}

• 33
• 34
• 35
• 36
• 37
• 38
• 39
• 40
• 41
• 42
• 43
• 44
• 45
• 46
• 47
• 48
• 49
• 50
• 51
• 52
• 53
• 54
• 55
• 56
• 57
• 58
• 59
• 60
• 61
• 62
• 63
• 64
• 65
• 66
• 67
• 68
• 69
• 70
• 71

@OverridepublicList<MethodMetadata> processAnnotationsOnMethod(MethodMetadata data,Method method,Annotation[] annotations){super.processAnnotationsOnMethod(data, method, annotations);for(Annotation methodAnnotation : annotations){RequestMapping methodAnnotation = findMergedAnnotation(method,RequestMapping.class);if(methodAnnotation !=null){// HTTP MethodRequestMethod[] methods = methodAnnotation.method();if(methods.length ==0){ methods =newRequestMethod[]{RequestMethod.GET };} checkOne(method, methods,"method"); data.template().method(Request.HttpMethod.valueOf(methods[0].name()));      // Path      checkAtMostOne(method, methodAnnotation.path(), "path");      if (StringUtils.hasText(methodAnnotation.path()[0])) {        String path = resolve(method, methodAnnotation.path()[0]);        if (!path.startsWith("/")) {          path = "/" + path;        }        data.template().uri(path);      }      // Produces      parseProduces(data, method, methodAnnotation.produces());      // Consumes      parseConsumes(data, method, methodAnnotation.consumes());      // Headers      parseHeaders(data, method, methodAnnotation.headers());      data.indexToExpander(new LinkedHashMap<>());    }  }  return Collections.singletonList(data);}

• 72
• 73
• 74
• 75
• 76
• 77
• 78
• 79
• 80
• 81
• 82
• 83
• 84
• 85
• 86
• 87
• 88
• 89
• 90
• 91
• 92
• 93
• 94
• 95
• 96
• 97
• 98
• 99
• 100
• 101
• 102
• 103
• 104
• 105
• 106

public static MethodHandler create(Target<?> target, Method method, MethodMetadata metadata,                                  RequestTemplate.Factory buildTemplateFromArgs,                                  Options options, Decoder decoder, ErrorDecoder errorDecoder,                                  Client client, Retryer retryer, List<RequestInterceptor> requestInterceptors,                                  Logger logger, Level logLevel) {  return new SynchronousMethodHandler(target, method, metadata, buildTemplateFromArgs, options,                                     decoder, errorDecoder, client, retryer, requestInterceptors, logger, logLevel);}@Overridepublic Object invoke(Object[] argv) throws Throwable {  RequestTemplate template = buildTemplateFromArgs.create(argv);  Options options = findOptions(argv);  Retryer retryer = this.retryer.clone();  while (true) {    try {      return executeAndDecode(template, options);    } catch (RetryableException e) {      try {        retryer.continueOrPropagate(e);      } catch (RetryableException th) {        Throwable cause = th.getCause();        if (propagationPolicy == UNWRAP && cause != null) {          throw cause;        } else {          throw th;        }      }      if (logLevel != Level.NONE) {        logger.logRetry(metadata.configKey(), logLevel);      }      continue;    }  }}

• 107
• 108
• 109
• 110
• 111
• 112
• 113
• 114
• 115
• 116
• 117
• 118
• 119
• 120
• 121
• 122
• 123
• 124
• 125
• 126
• 127
• 128
• 129
• 130
• 131
• 132
• 133
• 134
• 135
• 136
• 137
• 138
• 139
• 140
• 141
• 142
• 143

Object executeAndDecode(RequestTemplate template, Options options) throws Throwable {  Request request = targetRequest(template);  if (logLevel != Level.NONE) {    logger.logRequest(metadata.configKey(), logLevel, request);  }  Response response;  long start = System.nanoTime();  try {    response = client.execute(request, options);    // ensure the request is set. TODO: remove in Feign 12    response = response.toBuilder()        .request(request)        .requestTemplate(template)        .build();  } catch (IOException e) {    if (logLevel != Level.NONE) {      logger.logIOException(metadata.configKey(), logLevel, e, elapsedTime(start));    }    throw errorDecoder.decode(metadata.configKey(), e);  }  long elapsedTime = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start);  if (decoder != null) {    return decoder.decode(response, metadata.returnType());  }  return response;}Request targetRequest(RequestTemplate template) {  for (RequestInterceptor interceptor : requestInterceptors) {    interceptor.apply(template);  }  return target.apply(template);}