JarCastingvenus-cloud-feign
venus-cloud-feign,对Spring Cloud Feign的实战增强
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Release Note
| 版本 | spring boot版本 | spring cloud 版本 |
|---|---|---|
| 1.1.0 (开发中) | 2.1.x.RELEASE | Greenwich.RELEASE |
| 1.0.0 | 2.0.x.RELEASE | Finchley.RELEASE |
项目开发规范
包名规范
cn.springcloud.feign
使用
目前已经发布到Maven中央仓库：
<dependency>
<groupId>cn.springcloud.feign</groupId>
<artifactId>venus-cloud-starter-feign</artifactId>
<version>1.0.0</version>
</dependency>
应用场景
主要由于使用了API(SDK)为了偷懒，以及Restful API路径中的版本带来的一系列问题。
spring MVC 不支持继承接口中方法参数上的注解（支持继承类、方法上的注解）
API中为了方便，使用feign替代RestTemplate手动调用。带来的问题：springMVC注解想偷懒，只在feign接口写一遍，然后实现类继承此接口即可。 例如： feign接口定义如下
@FeignClient(ProviderApiAutoConfig.PLACE_HOLD_SERVICE_NAME)
public interface ProductService {
// 为了让spring mvc能够正确绑定变量
public class Page extends PageRequest<Product> {
}
@RequestMapping(value = "/{version}/pt/product", method = RequestMethod.POST)
Response<Product> insert(@RequestBody Product product);
}
service实现类方法参数必须再写一次@RequestBody注解，方法上的@RequestMapping注解可以省略
@RestController
public class ProductServiceImpl implements ProductService {
@Override
public Response<Product> insert(@RequestBody Product product) {
product.setId(1L);
return new Response(product);
}
}
解决办法，@Configuration配置类添加如下代码，扩展spring默认的ArgumentResolvers
public static MethodParameter interfaceMethodParameter(MethodParameter parameter, Class annotationType) {
if (!parameter.hasParameterAnnotation(annotationType)) {
for (Class<?> itf : parameter.getDeclaringClass().getInterfaces()) {
try {
Method method = itf.getMethod(parameter.getMethod().getName(), parameter.getMethod().getParameterTypes());
MethodParameter itfParameter = new MethodParameter(method, parameter.getParameterIndex());
if (itfParameter.hasParameterAnnotation(annotationType)) {
return itfParameter;
}
} catch (NoSuchMethodException e) {
continue;
}
}
}
return parameter;
}
@PostConstruct
public void modifyArgumentResolvers() {
List<HandlerMethodArgumentResolver> list = new ArrayList<>(adapter.getArgumentResolvers());
list.add(0, new PathVariableMethodArgumentResolver() { // PathVariable 支持接口注解
@Override
public boolean supportsParameter(MethodParameter parameter) {
return super.supportsParameter(interfaceMethodParameter(parameter, PathVariable.class));
}
@Override
protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
return super.createNamedValueInfo(interfaceMethodParameter(parameter, PathVariable.class));
}
});
list.add(0, new RequestHeaderMethodArgumentResolver(beanFactory) { // RequestHeader 支持接口注解
@Override
public boolean supportsParameter(MethodParameter parameter) {
return super.supportsParameter(interfaceMethodParameter(parameter, RequestHeader.class));
}
@Override
protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
return super.createNamedValueInfo(interfaceMethodParameter(parameter, RequestHeader.class));
}
});
list.add(0, new ServletCookieValueMethodArgumentResolver(beanFactory) { // CookieValue 支持接口注解
@Override
public boolean supportsParameter(MethodParameter parameter) {
return super.supportsParameter(interfaceMethodParameter(parameter, CookieValue.class));
}
@Override
protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
return super.createNamedValueInfo(interfaceMethodParameter(parameter, CookieValue.class));
}
});
list.add(0, new RequestResponseBodyMethodProcessor(adapter.getMessageConverters()) { // RequestBody 支持接口注解
@Override
public boolean supportsParameter(MethodParameter parameter) {
return super.supportsParameter(interfaceMethodParameter(parameter, RequestBody.class));
}
@Override
protected void validateIfApplicable(WebDataBinder binder, MethodParameter methodParam) { // 支持@Valid验证
super.validateIfApplicable(binder, interfaceMethodParameter(methodParam, Valid.class));
}
});
// 修改ArgumentResolvers, 支持接口注解
adapter.setArgumentResolvers(list);
}
swagger不支持继承接口中方法参数上的注解（支持继承类、方法上的注解）
没有找到swagger自带扩展点能够优雅扩展的方法，只好修改源码了，下载springfox-spring-web 2.8.0 release源码包。 添加pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>io.springfox</groupId>
<artifactId>springfox-spring-web</artifactId>
<version>2.8.0-charles</version>
<packaging>jar</packaging>
<properties>
<java.version>1.8</java.version>
<resource.delimiter>@</resource.delimiter>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<maven.compiler.source>${java.version}</maven.compiler.source>
<maven.compiler.target>${java.version}</maven.compiler.target>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<!--<version>2.0.0.RELEASE</version>-->
<version>1.5.10.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>0.9.11</version>
</dependency>
<!-- swagger -->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.8.0</version>
<exclusions>
<exclusion>
<groupId>io.springfox</groupId>
<artifactId>springfox-spring-web</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
</project>
添加ResolvedMethodParameterInterface继承ResolvedMethodParameter
public class ResolvedMethodParameterInterface extends ResolvedMethodParameter {
public ResolvedMethodParameterInterface(String paramName, MethodParameter methodParameter, ResolvedType parameterType) {
this(methodParameter.getParameterIndex(),
paramName,
interfaceAnnotations(methodParameter),
parameterType);
}
public ResolvedMethodParameterInterface(int parameterIndex, String defaultName, List<Annotation> annotations, ResolvedType parameterType) {
super(parameterIndex, defaultName, annotations, parameterType);
}
public static List<Annotation> interfaceAnnotations(MethodParameter methodParameter) {
List<Annotation> annotationList = new ArrayList<>();
annotationList.addAll(Arrays.asList(methodParameter.getParameterAnnotations()));
if (CollectionUtils.isEmpty(annotationList)) {
for (Class<?> itf : methodParameter.getDeclaringClass().getInterfaces()) {
try {
Method method = itf.getMethod(methodParameter.getMethod().getName(), methodParameter.getMethod().getParameterTypes());
MethodParameter itfParameter = new MethodParameter(method, methodParameter.getParameterIndex());
annotationList.addAll(Arrays.asList(itfParameter.getParameterAnnotations()));
} catch (NoSuchMethodException e) {
continue;
}
}
}
return annotationList;
}
}
修改HandlerMethodResolver类line 181，将ResolvedMethodParameter替换为ResolvedMethodParameterInterface，重新打包deploy，并在swagger相关依赖中强制指定修改后的版本。
<!-- swagger -->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
</dependency>
<!--扩展swagger支持从接口获得方法参数注解-->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-spring-web</artifactId>
<version>2.8.0-charles</version>
</dependency>
这样就能够顺利生产swagger文档啦。
feign不支持GET方法传递POJO
由于springMVC是支持GET方法直接绑定POJO的，只是feign实现并未覆盖所有springMVC特效，网上的很多变通方法都不是很好，要么是吧POJO拆散成一个一个单独的属性放在方法参数里，要么是把方法参数变成Map，要么就是要违反Restful规范，GET传递@RequestBody：
https://www.jianshu.com/p/7ce46c0ebe9d
https://github.com/spring-cloud/spring-cloud-netflix/issues/1253
解决办法，使用feign拦截器：
public class CharlesRequestInterceptor implements RequestInterceptor {
@Autowired
private ObjectMapper objectMapper;
@Override
public void apply(RequestTemplate template) {
// feign 不支持 GET 方法传 POJO, json body转query
if (template.method().equals("GET") && template.body() != null) {
try {
JsonNode jsonNode = objectMapper.readTree(template.body());
template.body(null);
Map<String, Collection<String>> queries = new HashMap<>();
buildQuery(jsonNode, "", queries);
template.queries(queries);
} catch (IOException e) {
e.printStackTrace();
}
}
}
private void buildQuery(JsonNode jsonNode, String path, Map<String, Collection<String>> queries) {
if (!jsonNode.isContainerNode()) { // 叶子节点
if (jsonNode.isNull()) {
return;
}
Collection<String> values = queries.get(path);
if (null == values) {
values = new ArrayList<>();
queries.put(path, values);
}
values.add(jsonNode.asText());
return;
}
if (jsonNode.isArray()) { // 数组节点
Iterator<JsonNode> it = jsonNode.elements();
while (it.hasNext()) {
buildQuery(it.next(), path, queries);
}
} else {
Iterator<Map.Entry<String, JsonNode>> it = jsonNode.fields();
while (it.hasNext()) {
Map.Entry<String, JsonNode> entry = it.next();
if (StringUtils.hasText(path)) {
buildQuery(entry.getValue(), path + "." + entry.getKey(), queries);
} else { // 根节点
buildQuery(entry.getValue(), entry.getKey(), queries);
}
}
}
}
}
feign不支持路径中的{version}
对于一个典型的Restful API定义如下：
@ApiOperation("带过滤条件和排序的分页查询")
@RequestMapping(value = "/{version}/pb/product", method = RequestMethod.GET)
// 当前版本新开发api 随微服务整体升级 pt=protected 受保护的网关token验证合法可调用
@ApiImplicitParam(name = "version", paramType = "path", allowableValues = ProviderApiAutoConfig.CURRENT_VERSION, required = true)
Response<PageData<Product, Product>> selectAllGet(Page page);
我们并不关心路径中的{version}，因此方法参数中也没有@PathVariable("version")，这个时候feign就傻了，不知道路径中的{version}应该被替换成什么值。 解决办法 使用自己的Contract替换SpringMvcContract，先将SpringMvcContract代码复制过来，修改其中processAnnotationOnMethod方法的代码，从swagger注解中获得{version}的值：
public class CharlesSpringMvcContract extends Contract.BaseContract
implements ResourceLoaderAware {
@Override
protected void processAnnotationOnMethod(MethodMetadata data,
Annotation methodAnnotation, Method method) {
if (!RequestMapping.class.isInstance(methodAnnotation) && !methodAnnotation
.annotationType().isAnnotationPresent(RequestMapping.class)) {
return;
}
RequestMapping methodMapping = AnnotatedElementUtils.findMergedAnnotation(method, RequestMapping.class);
// HTTP Method
RequestMethod[] methods = methodMapping.method();
if (methods.length == 0) {
methods = new RequestMethod[]{RequestMethod.GET};
}
checkOne(method, methods, "method");
data.template().method(methods[0].name());
// path
checkAtMostOne(method, methodMapping.value(), "value");
if (methodMapping.value().length > 0) {
String pathValue = Util.emptyToNull(methodMapping.value()[0]);
if (pathValue != null) {
pathValue = resolve(pathValue);
// Append path from @RequestMapping if value is present on method
if (!pathValue.startsWith("/")
&& !data.template().toString().endsWith("/")) {
pathValue = "/" + pathValue;
}
// 处理version
if (pathValue.contains("/{version}/")) {
Set<ApiImplicitParam> apiImplicitParams = AnnotatedElementUtils.findAllMergedAnnotations(method, ApiImplicitParam.class);
for (ApiImplicitParam apiImplicitParam : apiImplicitParams) {
if ("version".equals(apiImplicitParam.name())) {
String version = apiImplicitParam.allowableValues().split(",")[0].trim();
pathValue = pathValue.replaceFirst("\\{version\\}", version);
}
}
}
data.template().append(pathValue);
}
}
// produces
parseProduces(data, method, methodMapping);
// consumes
parseConsumes(data, method, methodMapping);
// headers
parseHeaders(data, method, methodMapping);
data.indexToExpander(new LinkedHashMap<Integer, Param.Expander>());
}
}
然后在自己的AutoConfig中声明成spring的bean
@Configuration
@ConditionalOnClass(Feign.class)
public class FeignAutoConfig {
@Bean
public Contract charlesSpringMvcContract(ConversionService conversionService) {
return new CharlesSpringMvcContract(Collections.emptyList(), conversionService);
}
@Bean
public CharlesRequestInterceptor charlesRequestInterceptor(){
return new CharlesRequestInterceptor();
}
}
