spring-cloud-feign在使用中遇到的一些问题

1. feign的接口继承特性

1.1 暴露的接口

package service.sys.common.api;

import com.ymu.spcselling.infrastructure.constants.SpcsConstants;
import com.ymu.spcselling.infrastructure.idgenerator.ID;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;
import service.sys.common.vo.req.VIdGenReq;

/**
 * 分布式id生成服务。
 */
@RequestMapping(SpcsConstants.API_VERSION + "/id")
public interface IdGenerateApi {

    /**
     * 生成分布式id
     * @param vIdGenReq 请求对象。body体
     * @return 生成的系统全局唯一id
     *
     * @api {post} /v1/id/gen 生成分布式id
     * @apiVersion 1.0.0
     * @apiName genId
     * @apiGroup ID
     * @apiPermission admin
     *
     * @apiDescription 通过数据中心id，机器id生成long型唯一id
     *
     * @apiParam {long} dataCenterId 数据中心id,0-31。
     * @apiParam {long} workerId 机器id，0-31。
     *
     * @apiParamExample {json} Request-Example:
     *     Request Headers
     *         Content-Type:application/json
     *     body:
     *     {
     *       "dataCenterId": 0,
     *       "workerId:" 0
     *     }
     *
     * @apiExample 请求例子:
     * curl -i http://localhost/user/4711
     *
     * @apiSuccess {long}   id      生成的id
     *
     * @apiError NoAccessRight 认证不通过
     * @apiError UserNotFound   The <code>id</code> of the User was not found.
     *
     * @apiErrorExample 响应例子:
     *     HTTP/1.1 401 Not Authenticated
     *     {
     *       "error": "NoAccessRight"
     *     }
     *
     * @apiSampleRequest url
     *
     */
    @PostMapping("/gen")
    long genId(@RequestBody @Validated VIdGenReq vIdGenReq);

    /**
     *
     * 解析分布式id
     * @param id
     * @return
     *
     * @api {post} /v1/id/expId  解析分布式id
     * @apiVersion 1.0.0
     * @apiName expId
     * @apiGroup ID
     * @apiPermission admin
     *
     * @apiDescription 把id解析成ID对象
     *
     * @apiParam {long} id 接口生成的id，必传。
     *
     * @apiExample 请求例子:
     *  http://localhost/v1/id/expId?id=352608540609069079
     *
     * @apiSuccess {long}   timeStamp     时间戳。41位的时间序列
     * @apiSuccess {long}   dataCenterId     数据中心id
     * @apiSuccess {long}   workerId     节点机器id
     * @apiSuccess {long}   sequence     序列号
     *
     * @apiError NoAccessRight 认证不通过
     *  //@apiError UserNotFound   The <code>id</code> of the User was not found.
     *
     * @apiErrorExample 响应例子:
     *     HTTP/1.1 401 Not Authenticated
     *     {
     *       "error": "NoAccessRight"
     *     }
     *
     * @apiSampleRequest http://localhost/v1/id/expId
     *
     */
    @GetMapping("/expId")
    ID expId(@RequestParam(value = "id") long id);
}

1.2 接口的实现

package service.sys.common.controller;

import com.ymu.spcselling.infrastructure.base.AbstractBaseController;
import com.ymu.spcselling.infrastructure.idgenerator.ID;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import service.sys.common.api.IdGenerateApi;
import service.sys.common.service.local.IdService;
import service.sys.common.vo.req.VIdGenReq;
import service.sys.common.vo.req.VIdGenReqValidator;

@RefreshScope
@RestController
public class IdGenerateController extends AbstractBaseController implements IdGenerateApi {

    private static final Logger LOGGER = LogManager.getLogger(SendEmailController.class);

    @Override
    protected void initBinder(WebDataBinder binder) {
        binder.addValidators(new VIdGenReqValidator());
    }


    @Autowired
    private IdService idService;

    @Override
    public long genId(@RequestBody VIdGenReq vIdGenReq) {
        long id = idService.genId(vIdGenReq.getDataCenterId(), vIdGenReq.getWorkerId());
        LOGGER.debug("genId:" + id);
        return id;
    }

    @Override
    public ID expId(long id) {
        ID ID = idService.expId(id);
        LOGGER.debug("ID=", ID.toString());
        return ID;
    }


}

注意：在gen()接口方法中，虽然加了mvn的参数注解@RequestBody @Validated，但是在其实现中也要加上，否则这些注解功能将失效。
类似的，还有一些其他的注解也要加上。

常见的在实现中要加上的注解有：

• @RequestBody
• @Validated
• @RequestHeader
• @RequestParam