springboot实现WebAPI版本控制

1.定义一个自定义版本注解

@Target({ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) public @interface ApiVersion {     /**      * @return版本号      */     int value( ) default 1; } 

2.自定义URL匹配规则ApiVersionCondition

package com.yangjunbo.helloword.properties;  import org.springframework.web.servlet.mvc.condition.RequestCondition;  import javax.servlet.http.HttpServletRequest; import java.util.regex.Matcher; import java.util.regex.Pattern;  /*接下来定义URL匹配逻辑，创建ApiVersionCondition类并继承RequestCondition接口，         其作用是进行版本号筛选，将提取请求URL中的版本号与注解上定义的版本号进行对比，以此来判断某个请求应落在哪个控制器上。*/ public class ApiVersionCondition implements RequestCondition<ApiVersionCondition> {     private final static Pattern VERSION_PREFIX_PATTERN = Pattern.compile(".*v(\\d+).*");      private int apiVersion;     ApiVersionCondition(int apiVersion) {         this.apiVersion = apiVersion;     }     private int getApiVersion() {         return apiVersion;     }      @Override     public ApiVersionCondition combine(ApiVersionCondition apiVersionCondition) {         return new ApiVersionCondition(apiVersionCondition.getApiVersion());     }     @Override     public ApiVersionCondition getMatchingCondition(HttpServletRequest httpServletRequest) {         Matcher m = VERSION_PREFIX_PATTERN.matcher(httpServletRequest.getRequestURI());         if (m.find()) {             Integer version = Integer.valueOf(m.group(1));             if (version >= this.apiVersion) {                 //apiVersion = version;                 return this;             }         }         return null;     }     @Override     public int compareTo(ApiVersionCondition apiVersionCondition, HttpServletRequest httpServletRequest) {         return apiVersionCondition.getApiVersion() - this.apiVersion;     } } 

3.使用RequestMappingHandlerMapping创建自定义的映射处理程序，根据Request参数匹配符合条件的处理程序

package com.yangjunbo.helloword.properties;  import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.servlet.mvc.condition.RequestCondition; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;  import java.lang.reflect.Method;  public class ApiRequestMappingHandlerMapping extends RequestMappingHandlerMapping {     private static final String VERSION_FLAG = "{version}";      private static RequestCondition<ApiVersionCondition> createCondition(Class<?> clazz) {         RequestMapping classRequestMapping = clazz.getAnnotation(RequestMapping.class);         if (classRequestMapping == null) {             return null;         }         StringBuilder mappingUrlBuilder = new StringBuilder();         if (classRequestMapping.value().length > 0) {             mappingUrlBuilder.append(classRequestMapping.value()[0]);         }         String mappingUrl = mappingUrlBuilder.toString();         if (!mappingUrl.contains(VERSION_FLAG)) {             return null;         }         ApiVersion apiVersion = clazz.getAnnotation(ApiVersion.class);         return apiVersion == null ? new ApiVersionCondition(1) : new ApiVersionCondition(apiVersion.value());     }     @Override     protected RequestCondition<?> getCustomMethodCondition(Method method) {         return createCondition(method.getClass());     }     @Override     protected RequestCondition<?> getCustomTypeCondition(Class<?> handlerType) {         return createCondition(handlerType);     } }  

4.配置注册自定义的RequestMappingHandlerMapping

package com.yangjunbo.helloword.properties;  import org.springframework.boot.autoconfigure.web.servlet.WebMvcRegistrations; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;  @Configuration public class WebMvcRegistrationsConfig implements WebMvcRegistrations {     @Override     public RequestMappingHandlerMapping getRequestMappingHandlerMapping() {         return new ApiRequestMappingHandlerMapping();     } }  

5.创建测试接口

package com.yangjunbo.helloword.controller.v1;  import com.yangjunbo.helloword.common.JSONResult; import com.yangjunbo.helloword.properties.ApiVersion; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController;  // V1 版本的接口定义 @RestController @RequestMapping("api/{version}/order") public class OrderV1Controller {     @GetMapping("/delete/{orderId}")     public JSONResult deleteOrderById(@PathVariable String orderId) {         System.out.println("V1删除订单成功："+orderId);         return JSONResult.ok("V1删除订单成功");     }      @GetMapping("/detail/{orderId}")     public JSONResult queryOrderById(@PathVariable String orderId) {         System.out.println("V1获取订单详情成功："+orderId);         return JSONResult.ok("V1获取订单详情成功");     } }   

package com.yangjunbo.helloword.controller.v2;  import com.yangjunbo.helloword.common.JSONResult; import com.yangjunbo.helloword.properties.ApiVersion; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController;  // V2 版本的接口定义 @ApiVersion(2) @RestController @RequestMapping("api/{version}/order") public class OrderV2Controller {     @GetMapping("/detail/{orderId}")     public JSONResult queryOrdearById(@PathVariable String orderId) {         System.out.println("V2获取订单详情成功："+orderId);         return JSONResult.ok("V2获取订单详情成功");     }      @GetMapping("/list")     public JSONResult list() {         System.out.println("V2,新增list订单列表接口");         return JSONResult.ok(200,"V2,新增list订单列表接口");     } }   

6.访问接口测试

以上验证情况说明Web API的版本控制配置成功，实现了旧版本的稳定和新版本的更新。
1）当请求正确的版本地址时，会自动匹配版本的对应接口。
2）当请求的版本大于当前版本时，默认匹配最新的版本。
3）高版本会默认继承低版本的所有接口。实现版本升级只关注变化的部分，没有变化的部分会自动平滑升级，这就是所谓的版本继承。
4）高版本的接口的新增和修改不会影响低版本。
这些特性使得在升级接口时，原有接口不受影响，只关注变化的部分，没有变化的部分自动平滑升级。这样使得Web API更加简洁，这就是实现Web API版本控制的意义所在。
参考书籍 《springboot从入门到实战-章为忠著》