[转]如何优雅的设计 Spring Boot API 接口版本号

原文:https://blog.mariojd.cn/how-to-design-spring-boot-api-version-number-elegantly.html

 

  一般来说,系统上线以后,需求仍会发生变动,功能也会迭代更新。可能是接口参数发生变更,也有可能是业务逻辑需要调整,如果直接在原来的接口上进行修改,必然会影响原有服务的正常运行。

   常见的解决方案,是在接口路径中加入版本号用于区分,此外还可以在参数甚至 header 里带上版本号。这里以在请求路径中带上版本号为例,如:http://IP:PORT/api/v1/test ,v1 即代表的是版本号。当然了,可以像这样,直接写死在 @RequestMapping("api/v1/test") 属性中,不过下面提供了更为优雅的解决方案。

1. 自定义版本号标记注解:

@Target({ElementType.METHOD, ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ApiVersion {

    /**
     * 标识版本号,从1开始
     */
    int value() default 1;

}

 

2. 重写相应的 RequestCondition

@Data
@Slf4j
public class ApiVersionCondition implements RequestCondition<ApiVersionCondition> {

    /**
     * 接口路径中的版本号前缀,如: api/v[1-n]/test
     */
    private final static Pattern VERSION_PREFIX_PATTERN = Pattern.compile("/v(\\d+)/");

    private int apiVersion;

    ApiVersionCondition(int apiVersion) {
        this.apiVersion = apiVersion;
    }

    /**
     * 最近优先原则,方法定义的 @ApiVersion > 类定义的 @ApiVersion
     */
    @Override
    public ApiVersionCondition combine(ApiVersionCondition other) {
        return new ApiVersionCondition(other.getApiVersion());
    }

    /**
     * 获得符合匹配条件的ApiVersionCondition
     */
    @Override
    public ApiVersionCondition getMatchingCondition(HttpServletRequest request) {
        Matcher m = VERSION_PREFIX_PATTERN.matcher(request.getRequestURI());
        if (m.find()) {
            int version = Integer.valueOf(m.group(1));
            if (version >= getApiVersion()) {
                return this;
            }
        }
        return null;
    }

    /**
     * 当出现多个符合匹配条件的ApiVersionCondition,优先匹配版本号较大的
     */
    @Override
    public int compareTo(ApiVersionCondition other, HttpServletRequest request) {
        return other.getApiVersion() - getApiVersion();
    }

}

 

3. 重写部分 RequestMappingHandlerMapping 的方法

public class CustomRequestMappingHandlerMapping extends RequestMappingHandlerMapping {

    @Override
    protected RequestCondition<?> getCustomTypeCondition(Class<?> handlerType) {
        // 扫描类上的 @ApiVersion
        ApiVersion apiVersion = AnnotationUtils.findAnnotation(handlerType, ApiVersion.class);
        return createRequestCondition(apiVersion);
    }

    @Override
    protected RequestCondition<?> getCustomMethodCondition(Method method) {
        // 扫描方法上的 @ApiVersion
        ApiVersion apiVersion = AnnotationUtils.findAnnotation(method, ApiVersion.class);
        return createRequestCondition(apiVersion);
    }

    private RequestCondition<ApiVersionCondition> createRequestCondition(ApiVersion apiVersion) {
        if (Objects.isNull(apiVersion)) {
            return null;
        }
        int value = apiVersion.value();
        Assert.isTrue(value >= 1, "Api Version Must be greater than or equal to 1");
        return new ApiVersionCondition(value);
    }

}

 

4. 配置注册自定义的 CustomRequestMappingHandlerMapping

@Slf4j
@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {

    @Override
    public RequestMappingHandlerMapping requestMappingHandlerMapping() {
        return new CustomRequestMappingHandlerMapping();
    }

}

 

5. 编写接口,标记上相应的 @ApiVersion

@Slf4j
@ApiVersion
@RestController
@RequestMapping("api/{version}/test")
public class TestController {

    @GetMapping
    public String test01(@PathVariable String version) {
        return "test01 : " + version;
    }

    @GetMapping
    @ApiVersion(2)
    public String test02(@PathVariable String version) {
        return "test02 : " + version;
    }

}

 

6. 启动 Application,测试及查看结果

posted @ 2019-12-25 15:43  闲人鹤  阅读(2053)  评论(0编辑  收藏  举报