这篇文章主要讲解了“springmvc实现restful api版本控制并兼容swagger的方法”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“springmvc实现restful api版本控制并兼容swagger的方法”吧！
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开发的时候经常会出现接口的变更，而接口的变更又常需兼容老的客户端版本，此时便需要做接口的版本控制，比较好的方案是在header带上version参数，但是不排除有些在url上做控制的，类似/v1/xxx/xxx，/v2_0/xxx/xxx，此文为第二种，使用如下：
[@RestController](https://my.oschina.net/u/4486326)
@Api(value = "测试", tags = {"测试"})
@RequestMapping("/{version}/test/")
public class TestController {
@Autowired
private TestService testService;
@ApiOperation(value = "测试接口", notes = "测试")
@PostMapping(value = "test")
@ApiVersion("1_0")
public Object region(@RequestBody TestReq model) {
return testService.test(model);
}
}首先是@ApiVersion的使用，定义如下
import org.springframework.web.bind.annotation.Mapping; import java.lang.annotation.*; /** \* ClassName: ApiVersion
\* Function: url版本注解
\* Reason: value书写格式 n\_n，匹配规则为小于等于n\_n最近的一个版本，示例如下： \* 现有接口 v1\_0,v1\_1,v2\_0,v2\_3 \* 访问 v1\_1/xxx 执行： v1\_1 \* 访问 v1\_2/xxx 执行： v1\_1 \* 访问 v2\_1/xxx 执行： v2\_0 \* 访问 v4\_0/xxx 执行： v2\_3 \*
\* Date: 2017-10-31 14:33
* \* @author zoro */ @Target({ElementType.METHOD, ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) @Documented @Mapping public @interface ApiVersion { // 版本号 String value(); }
接下来是自定义条件选择器，当请求进来可以正确匹对需要调用的方法
import org.springframework.web.servlet.mvc.condition.RequestCondition; import javax.servlet.http.HttpServletRequest; import java.util.regex.Matcher; import java.util.regex.Pattern; /** \* ClassName: ApiVesrsionCondition
\* Function: API版本条件筛选器
\* Reason: TODO ADD REASON(可选)
\* Date: 2017-10-31 14:35
* \* @author zoro */ public class ApiVesrsionCondition implements RequestCondition{ private String apiVersion; public ApiVesrsionCondition(String apiVersion){ this.apiVersion = apiVersion; } public ApiVesrsionCondition combine(ApiVesrsionCondition other) { // 采用最后定义优先原则，则方法上的定义覆盖类上面的定义 return new ApiVesrsionCondition(other.getApiVersion()); } public ApiVesrsionCondition getMatchingCondition(HttpServletRequest request) { if (compare(getPathInfo(request)) >= 0) { return this; } return null; } public int compareTo(ApiVesrsionCondition other, HttpServletRequest request) { // 优先匹配最新的版本号 return compare("v" + other.getApiVersion() + "/"); } public String getApiVersion() { return apiVersion; } private String getPathInfo(HttpServletRequest request) { String uri = request.getRequestURI(); String contextPath = request.getContextPath(); if (contextPath != null && contextPath.length() > 0) { uri = uri.substring(contextPath.length()); } return uri; } /** \* Description: 这里是版本的控制规则，不是很优雅，时间有限，写死了只识别vn_n的格式.
\* Date: 2017/11/10.
\* @param version \* @return \* @throws */ private int compare(String version) { // 路径中版本的前缀， 这里用 /v\[0-9\]_\[0-9\]/的形式 Pattern req\_patten = Pattern.compile("v(\\\d+)\_(\\\d+)/"); // api版本的前缀， 这里用 \[0-9\]_\[0-9\]的形式 Pattern api\_patten = Pattern.compile("(\\\d+)\_(\\\d+)"); Matcher req\_m = req\_patten.matcher(version); Matcher api\_m = api\_patten.matcher(this.apiVersion); if (req\_m.find() && api\_m.find()) { Integer first\_version = Integer.valueOf(req\_m.group(1)); Integer first\_apiVersion = Integer.valueOf(api\_m.group(1)); // 如果请求的版本号大于配置版本号， 则满足 if(first\_version > first\_apiVersion) { return 1; } else if (first\_version == first\_apiVersion) { Integer last\_version = Integer.valueOf(req\_m.group(2)); Integer last\_apiVersion = Integer.valueOf(api\_m.group(2)); if(last\_version > last\_apiVersion) { return 1; } else if (last\_version == last\_apiVersion) { return 0; } } } return -1; } }
我们知道springmvc默认是用RequestMappingInfoHandlerMapping根据RequestMappingInfo来匹配条件的，所以我们自定义一个Handler来修改RequestMappingInfoHandlerMapping原有的匹配规则
import org.springframework.core.annotation.AnnotationUtils; import org.springframework.web.servlet.mvc.condition.RequestCondition; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping; import java.lang.reflect.Method; /** \* ClassName: CustomRequestMappingHandlerMapping
\* Function: TODO ADD FUNCTION(可选)
\* Reason: TODO ADD REASON(可选)
\* Date: 2017-10-31 15:13
* \* @author zoro */ public class CustomRequestMappingHandlerMapping extends RequestMappingHandlerMapping { @Override protected RequestConditiongetCustomTypeCondition(Class handlerType) { ApiVersion apiVersion = AnnotationUtils.findAnnotation(handlerType, ApiVersion.class); return createCondition(apiVersion); } @Override protected RequestCondition getCustomMethodCondition(Method method) { ApiVersion apiVersion = AnnotationUtils.findAnnotation(method, ApiVersion.class); return createCondition(apiVersion); } private RequestCondition createCondition(ApiVersion apiVersion) { return apiVersion == null ? null : new ApiVesrsionCondition(apiVersion.value()); } }
最后，只需要重新装配一下自定义的HandlerMapping即可
import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping; /** \* ClassName: WebConfig
\* Function: TODO ADD FUNCTION(可选)
\* Reason: TODO ADD REASON(可选)
\* Date: 2017-10-31 15:15
* \* @author zoro */ @Configuration public class WebConfig extends WebMvcConfigurationSupport { @Override @Bean public RequestMappingHandlerMapping requestMappingHandlerMapping() { RequestMappingHandlerMapping handlerMapping = new CustomRequestMappingHandlerMapping(); handlerMapping.setOrder(0); handlerMapping.setInterceptors(getInterceptors()); return handlerMapping; } }
至此，便可以正常的使用了，但是如果项目引入了swagger的，会发现一个问题，项目启动后，swagger页面无法打开，这是因为继承WebMvcConfigurationSupport后，静态文件的映射出现了问题，需要重新指定一下，WebConfig修改如下：
import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer; import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry; import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping; /** \* ClassName: WebConfig
\* Function: TODO ADD FUNCTION(可选)
\* Reason: TODO ADD REASON(可选)
\* Date: 2017-10-31 15:15
* \* @author zoro */ @Configuration public class WebConfig extends WebMvcConfigurationSupport { @Override @Bean public RequestMappingHandlerMapping requestMappingHandlerMapping() { RequestMappingHandlerMapping handlerMapping = new CustomRequestMappingHandlerMapping(); handlerMapping.setOrder(0); handlerMapping.setInterceptors(getInterceptors()); return handlerMapping; } /** \* 发现如果继承了WebMvcConfigurationSupport，则在yml中配置的相关内容会失效。 \* 需要重新指定静态资源 \* @param registry */ @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry.addResourceHandler("/**").addResourceLocations("classpath:/static/"); registry.addResourceHandler("swagger-ui.html") .addResourceLocations("classpath:/META-INF/resources/"); registry.addResourceHandler("/webjars/**") .addResourceLocations("classpath:/META-INF/resources/webjars/"); super.addResourceHandlers(registry); } /** \* 配置servlet处理 */ @Override public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) { configurer.enable(); } }
此时，swagger也能正常打开了，却发现swagger生成的api文档是{version}/xxx/xxx的，这就非常恶心了，我们知道，springmvc的映射信息是放在RequestMappingInfo里的，先来看一段RequestMappingHandlerMapping的源码
public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMapping implements MatchableHandlerMapping, EmbeddedValueResolverAware {
.......上面的代码省略......
protected RequestMappingInfo getMappingForMethod(Method method, Class handlerType) {
RequestMappingInfo info = this.createRequestMappingInfo(method);
if (info != null) {
RequestMappingInfo typeInfo = this.createRequestMappingInfo(handlerType);
if (typeInfo != null) {
info = typeInfo.combine(info);
}
}
return info;
}
private RequestMappingInfo createRequestMappingInfo(AnnotatedElement element) {
RequestMapping requestMapping = (RequestMapping)AnnotatedElementUtils.findMergedAnnotation(element, RequestMapping.class);
RequestCondition condition = element instanceof Class ? this.getCustomTypeCondition((Class)element) : this.getCustomMethodCondition((Method)element);
return requestMapping != null ? this.createRequestMappingInfo(requestMapping, condition) : null;
}
protected RequestCondition getCustomTypeCondition(Class handlerType) {
return null;
}
protected RequestCondition getCustomMethodCondition(Method method) {
return null;
}
protected RequestMappingInfo createRequestMappingInfo(RequestMapping requestMapping, RequestCondition customCondition) {
return RequestMappingInfo.paths(this.resolveEmbeddedValuesInPatterns(requestMapping.path())).methods(requestMapping.method()).params(requestMapping.params()).headers(requestMapping.headers()).consumes(requestMapping.consumes()).produces(requestMapping.produces()).mappingName(requestMapping.name()).customCondition(customCondition).options(this.config).build();
}
.......下面的代码省略......
}从getMappingForMethod方法可以知道，springmvc是先读取方法上的@RequestMapping上的value，再读类上@RequestMapping上的value，然后两个值拼接在一起，理论上是可以在生成RequestMappingInfo后通过反射修改RequestMappingInfo里的值来达到目的的，这里想折腾一下，从createRequestMappingInfo的时候入手，通过改变注解上的value来达到效果，修改CustomRequestMappingHandlerMapping类如下
import org.springframework.core.annotation.AnnotatedElementUtils; import org.springframework.core.annotation.AnnotationUtils; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.mvc.condition.RequestCondition; import org.springframework.web.servlet.mvc.method.RequestMappingInfo; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping; import java.lang.reflect.*; import java.util.Map; /** \* ClassName: CustomRequestMappingHandlerMapping
\* Function: TODO ADD FUNCTION(可选)
\* Reason: TODO ADD REASON(可选)
\* Date: 2017-10-31 15:13
* \* @author zoro */ public class CustomRequestMappingHandlerMapping extends RequestMappingHandlerMapping { @Override protected RequestConditiongetCustomTypeCondition(Class handlerType) { ApiVersion apiVersion = AnnotationUtils.findAnnotation(handlerType, ApiVersion.class); return createCondition(apiVersion); } @Override protected RequestCondition getCustomMethodCondition(Method method) { ApiVersion apiVersion = AnnotationUtils.findAnnotation(method, ApiVersion.class); return createCondition(apiVersion); } private RequestCondition createCondition(ApiVersion apiVersion) { return apiVersion == null ? null : new ApiVesrsionCondition(apiVersion.value()); } @Override protected RequestMappingInfo getMappingForMethod(Method method, Class handlerType) { RequestMappingInfo info = this.createRequestMappingInfo(method, null); if (info != null) { ApiVersion apiVersion = (ApiVersion) AnnotatedElementUtils.findMergedAnnotation(method, ApiVersion.class); RequestMappingInfo typeInfo = this.createRequestMappingInfo(handlerType, apiVersion); if (typeInfo != null) { info = typeInfo.combine(info); } } return info; } private RequestMappingInfo createRequestMappingInfo(AnnotatedElement element, ApiVersion apiVersion) { RequestMapping requestMapping = (RequestMapping) AnnotatedElementUtils.findMergedAnnotation(element, RequestMapping.class); RequestCondition condition = element instanceof Class ? this.getCustomTypeCondition((Class)element) : this.getCustomMethodCondition((Method)element); if (element instanceof Class && null != apiVersion) { try { // 动态修改RequestMapping注解的属性 InvocationHandler invocationHandler = Proxy.getInvocationHandler(requestMapping); Field field = invocationHandler.getClass().getDeclaredField("valueCache"); // SynthesizedAnnotationInvocationHandler的valueCache是私有变量，需要打开权限 field.setAccessible(true); Map map = (Map) field.get(invocationHandler); String\[\] paths = new String\[requestMapping.path().length\]; for (int i = 0; i< requestMapping.path().length; i++) { paths\[i\] = requestMapping.path()\[i\].replace("{version}", "v".concat(apiVersion.value())); } map.put("path", paths); String\[\] values = new String\[requestMapping.value().length\]; for (int i = 0; i< requestMapping.value().length; i++) { values\[i\] = requestMapping.value()\[i\].replace("{version}", "v".concat(apiVersion.value())); } map.put("value", values); // 上面改了value和path是因为注解里@AliasFor，两者互为，不晓得其它地方有没有用到，所以都改了，以免其它问题 } catch (Exception e) { e.printStackTrace(); } } return requestMapping != null ? this.createRequestMappingInfo(requestMapping, condition) : null; } }
感谢各位的阅读，以上就是“springmvc实现restful api版本控制并兼容swagger的方法”的内容了，经过本文的学习后，相信大家对springmvc实现restful api版本控制并兼容swagger的方法这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是创新互联，小编将为大家推送更多相关知识点的文章，欢迎关注！
