通用查询的抽象

有一批查询接口，只有参数，返回值，接口地址不通，如何抽象出通用的调用方式呢？

分析一下，每个接口返回类型不一样，我想到了泛型，参数，接口地址不一样，可以通过参数区分。于是先定义一个带泛型的接口

public interface CommonQueryService<T> {    /**     * 通用查询     * @param requestDto 请求dto     * @param apiUrl  请求地址     * @param msg 日志消息表示     * @return 查询返回对象     * @throws InvalidCipherTextException     */    GenericReturnObject<List<T>> commonQuery(Object requestDto,String apiUrl, String msg)  throws InvalidCipherTextException;}

谁来实现它呢？我定义一个实现类吧

@Slf4jpublic abstract class CommonQueryServiceImpl<T> implements CommonQueryService<T> {    @Autowired    private BusinessCenterTokenHelper businessCenterTokenHelper;    @Autowired    private EpServiceConfig epServiceConfig;    protected String returnJson;    public GenericReturnObject<List<T>> commonQuery(Object requestDto,String apiUrl,String msg) throws InvalidCipherTextException {        String jsonBody = com.alibaba.fastjson.JSON.toJSONString(requestDto);        long date = System.currentTimeMillis();        log.info("esServiceConfig:{}", com.alibaba.fastjson.JSON.toJSONString(epServiceConfig));        String appPubKey = epServiceConfig.getApp().getPubkey() ;        log.info("appPubKey:{}",appPubKey);        String  token = businessCenterTokenHelper.getToken();        log.info("token:{}",token);        String signature = EncryptUtil.sign("POST" + '\n' + date + '\n'+ token + '\n' + appPubKey +'\n'+ jsonBody);        log.info("signature:{}",signature);        String dateX = String.valueOf(date);        log.info("dataX:{}",dateX);        EPRequestCaller caller = null;        try {            caller = EPRequestCaller.newBuilder(apiUrl)                    .token(token)                    .apiVersion(epServiceConfig.getApp().getVersion())                    .clientId(epServiceConfig.getClient().getId())                    .putHeadParamsMap("x-date", dateX)                    .putHeadParamsMap("x-token",token)                    .putHeadParamsMap("x-signature",signature)                    .appPubKey(appPubKey);            caller.setContentBody(jsonBody);            this.returnJson = caller.doPost();            GenericReturnObject<List<T>> returnObject = convertJson(returnJson);            log.info(">>>>>>>>>>>>>>>>>>>>>>>>>{}，返回:{}>>>>>>>>>>>>>>>>>>>>>",msg, com.alibaba.fastjson.JSON.toJSONString(returnObject));            return returnObject;        } catch (HttpCallerException e) {            log.error("msg:{} 失败：{}",msg,e);            GenericReturnObject genericReturnObject = new GenericReturnObject();            genericReturnObject.setErrors(e.getMessage());            return genericReturnObject;        } catch (Exception e) {            log.error("msg:{}.e:{}",msg,e);            GenericReturnObject genericReturnObject = new GenericReturnObject();            genericReturnObject.setErrors(e.getMessage());            return genericReturnObject;        }    }    /**     * 中台返回的json转换为json对象,由子类实现     * @param json     * @return 返回对象     */    public abstract GenericReturnObject<List<T>> convertJson(String json);

大家看到这是一个抽象类，本来不打算用抽象类的，奈何JSON转对象的时候，不支持泛型的转换，于是定义为抽象类，再定义一个抽象方法 convertJson，把转换的工作交给子类来实现，这样就不涉及JSON转泛型对象的问题了。

对于不同的查询，再定义不用的实现类继承上述抽象类，并实现通用查询接口。下面举2个例子。

@Service("commonQueryServiceFire")public class CommonQueryServiceFireImpl<FireInfoDto> extends CommonQueryServiceImpl<FireInfoDto> implements CommonQueryService<FireInfoDto> {    @Override    public GenericReturnObject<List<FireInfoDto>> commonQuery(Object requestDto, String apiUrl,String msg) throws InvalidCipherTextException {        GenericReturnObject<List<FireInfoDto>> listGenericReturnObject = super.commonQuery(requestDto, apiUrl,msg);        return listGenericReturnObject;    }    @Override    public GenericReturnObject<List<FireInfoDto>> convertJson(String json) {            GenericReturnObject<List<FireInfoDto>> returnObject = com.alibaba.fastjson.JSON.parseObject(returnJson,                new TypeReference<GenericReturnObject<List<FireInfoDto>>>(){});        return returnObject;    }}

@Service("commonQueryServiceFireReport")public class CommonQueryServiceFireReport<ForecastReportDto> extends CommonQueryServiceImpl<ForecastReportDto> implements CommonQueryService<ForecastReportDto> {    @Override    public GenericReturnObject<List<ForecastReportDto>> commonQuery(Object requestDto, String apiUrl,String msg) throws InvalidCipherTextException {        GenericReturnObject<List<ForecastReportDto>> listGenericReturnObject = super.commonQuery(requestDto, apiUrl,msg);        return listGenericReturnObject;    }    @Override    public GenericReturnObject<List<ForecastReportDto>> convertJson(String json) {            GenericReturnObject<List<ForecastReportDto>> returnObject = com.alibaba.fastjson.JSON.parseObject(returnJson,                new TypeReference<GenericReturnObject<List<ForecastReportDto>>>(){});        return returnObject;    }}

controller调用端

@Resource(name = "commonQueryServiceFire")private CommonQueryService commonQueryServiceFire;@Resource(name = "commonQueryServiceFireReport")private CommonQueryService commonQueryServiceFireReport;

 
@PostMapping("/environCenter/fire/fireRealData")
public GenericReturnObject fireRealData(String date,
                                           String  fireCode ) throws Exception { 
    FireRealDataReqDto fireRealDataReqDto = new FireRealDataReqDto();
    fireRealDataReqDto.setFireCode(fireCode);
    fireRealDataReqDto.setDate(date);
    GenericReturnObject<List<FireInfoDto>> listGenericReturnObject = commonQueryServiceFire.commonQuery(fireRealDataReqDto,
            "/environCenter/fire/fireRealData",
            "查询xxx信息"); 
    return listGenericReturnObject;
}
 
@PostMapping("/environCenter/fire/fireReport")
public GenericReturnObject fireReport(String date  ) throws Exception { 
            date );
    FireReportReqDto fireReportReqDto = new FireReportReqDto();
    fireReportReqDto.setDate(date);
    GenericReturnObject<List<ForecastReportDto>> listGenericReturnObject = commonQueryServiceFireReport.commonQuery(fireReportReqDto,
            "/environCenter/fire/fireReport",
            "yyy查询"); 
    return listGenericReturnObject;
}

 新增不用的查询，需要增加新的实现类，参数dto，返回dto，调用方注入实现类，调用commonQuery方法即可。隐藏了调用细节，不必拷贝重复的代码。（代码删除了注释部分，避免不必要的隐私泄露）。