背景

由于项目的规范需要，需要统一的api接口形式，由于接口可能存在不同的api版本，所以一般是在api接口url上会跟上版本号，例如:

• /api/1.0/user/info
• /api/1.2/user/info
  如果针对这种url，不加以规范，可能存在很多问题，比如说api前缀的长度，命名规范等问题。
  所以可以针对SpringCloud微服务进行一些url规范。通过结合@RequestMapping 注解，可能新增一个@ApiVersion注解，在映射Url之前，根据规范添加前缀。

直接上代码：

WebMvcConfig:

package com.scio.core.config.web;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

@Configuration
public class WebMvcConfig extends WebMvcConfigurationSupport {

    @Override
    protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
        return new ApiVersionHandlerMapping();
    }
}

ApiVersion:

package com.scio.core.config.web;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

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

    String value();
}

ApiVersionHandlerMapping:

package com.scio.core.config.web;

import java.lang.reflect.Method;

import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.web.servlet.mvc.condition.PatternsRequestCondition;
import org.springframework.web.servlet.mvc.method.RequestMappingInfo;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class ApiVersionHandlerMapping extends RequestMappingHandlerMapping {

    @Override
    protected RequestMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
        RequestMappingInfo requestMapping = super.getMappingForMethod(method, handlerType);
        ApiVersion version = AnnotationUtils.findAnnotation(method, ApiVersion.class);
        if (version != null) {
            PatternsRequestCondition prc = requestMapping.getPatternsCondition();
            final String v = version.value();
            PatternsRequestCondition prefix = new PatternsRequestCondition(String.format("/api/%s", v));
            if (log.isDebugEnabled()) {
                log.debug("add api prefix for {}", prc.getPatterns());
            }
            prefix = prefix.combine(prc);
            requestMapping = new RequestMappingInfo(prefix, requestMapping.getMethodsCondition(),
                requestMapping.getParamsCondition(), requestMapping.getHeadersCondition(),
                requestMapping.getConsumesCondition(), requestMapping.getProducesCondition(),
                requestMapping.getCustomCondition());
        }
        return requestMapping;
    }
}

TestController:

package com.scio.core.config.web;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {
    @RequestMapping("/test")
    @ApiVersion("1.0")
    public void test() {
        System.out.println("test");
    }
}