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1 分层思维
计算机范畴有一句话:计算机中任何问题都可经过添加一个虚拟层解决。这句体现了分层思维重要性,分层思维同样适用于Java工程架构。
分层长处是每层只专注本层作业,能够类比规划形式单一责任准则,或许经济学比较优势原理,每层只做本层最擅长的工作。
分层缺点是层之间通讯时,需求经过适配器,翻译本钱层或许基层能够了解的信息,通讯本钱有所添加。
我认为工程分层需求从五个维度思考:
(1) 单一
每层只处理一类工作,满意单一责任准则
(2) 降噪
信息在每一层进行传输,满意最小常识准则,只向基层传输必要信息
(3) 适配
每层都需求一个适配器,翻译信息为本层或许基层能够了解的信息
(4) 事务
事务目标能够整合事务逻辑,例如运用充血模型整合事务
(5) 数据
数据目标尽量纯洁,尽量不要聚合事务
1.2 九层结构
综上所述SpringBoot工程能够分为九层:
- 东西层:util
- 整合层:integration
- 根底层:infrastructure
- 服务层:service
- 范畴层:domain
- 门面层:facade
- 操控层:controller
- 客户端:client
- 发动层:boot
2 分层详解
创立测验项目user-demo-service:
user-demo-service
-user-demo-service-boot
-user-demo-service-client
-user-demo-service-controller
-user-demo-service-domain
-user-demo-service-facade
-user-demo-service-infrastructure
-user-demo-service-integration
-user-demo-service-service
-user-demo-service-util
2.1 util
东西层承载东西代码
不依靠本项目其它模块
只依靠一些通用东西包
user-demo-service-util
-/src/main/java
-date
-DateUtil.java
-json
-JSONUtil.java
-validate
-BizValidator.java
2.2 infrastructure
根底层中心是承载数据访问,entity实体目标承载在本层。
2.2.1 项目结构
代码层分为两个范畴:
- player:运动员
- game:竞赛
每个范畴具有两个子包:
- entity
- mapper
user-demo-service-infrastructure
-/src/main/java
-player
-entity
-PlayerEntity.java
-mapper
-PlayerEntityMapper.java
-game
-entity
-GameEntity.java
-mapper
-GameEntityMapper.java
-/src/main/resources
-mybatis
-sqlmappers
-gameEntityMappler.xml
-playerEntityMapper.xml
2.2.2 本项目间依靠联系
infrastructure只依靠东西模块
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-util</artifactId>
</dependency>
2.2.3 中心代码
创立运动员数据表:
CREATE TABLE `player` (
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键',
`player_id` varchar(256) NOT NULL COMMENT '运动员编号',
`player_name` varchar(256) NOT NULL COMMENT '运动员名称',
`height` int(11) NOT NULL COMMENT '身高',
`weight` int(11) NOT NULL COMMENT '体重',
`game_performance` text COMMENT '最近一场竞赛体现',
`creator` varchar(256) NOT NULL COMMENT '创立人',
`updator` varchar(256) NOT NULL COMMENT '修正人',
`create_time` datetime NOT NULL COMMENT '创立时刻',
`update_time` datetime NOT NULL COMMENT '修正时刻',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8
运动员实体目标,gamePerformance字段作为string保存在数据库,这体现了数据层尽量纯洁,不要整合过多事务,解析使命应该放在事务层:
public class PlayerEntity {
private Long id;
private String playerId;
private String playerName;
private Integer height;
private Integer weight;
private String creator;
private String updator;
private Date createTime;
private Date updateTime;
private String gamePerformance;
}
运动员Mapper目标:
@Repository
public interface PlayerEntityMapper {
int insert(PlayerEntity record);
int updateById(PlayerEntity record);
PlayerEntity selectById(@Param("playerId") String playerId);
}
2.3 domain
2.3.1 概念阐明
范畴层是DDD流行鼓起之概念
能够经过三组对比了解范畴层
- 范畴目标 VS 数据目标
- 范畴目标 VS 事务目标
- 范畴层 VS 事务层
(1) 范畴目标 VS 数据目标
数据目标字段尽量纯洁,运用基本类型
public class PlayerEntity {
private Long id;
private String playerId;
private String playerName;
private Integer height;
private Integer weight;
private String creator;
private String updator;
private Date createTime;
private Date updateTime;
private String gamePerformance;
}
以查询成果范畴目标为例
范畴目标需求体现事务意义
public class PlayerQueryResultDomain {
private String playerId;
private String playerName;
private Integer height;
private Integer weight;
private GamePerformanceVO gamePerformance;
}
public class GamePerformanceVO {
// 跑动间隔
private Double runDistance;
// 传球成功率
private Double passSuccess;
// 进球数
private Integer scoreNum;
}
(2) 范畴目标 VS 事务目标
事务目标同样会体现事务,范畴目标和事务目标有什么不同呢?其中一个最大不同是范畴目标采用充血模型聚合事务。
运动员新增事务目标:
public class PlayerCreateBO {
private String playerName;
private Integer height;
private Integer weight;
private GamePerformanceVO gamePerformance;
private MaintainCreateVO maintainInfo;
}
运动员新增范畴目标:
public class PlayerCreateDomain implements BizValidator {
private String playerName;
private Integer height;
private Integer weight;
private GamePerformanceVO gamePerformance;
private MaintainCreateVO maintainInfo;
@Override
public void validate() {
if (StringUtils.isEmpty(playerName)) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == height) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (height > 300) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == weight) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null != gamePerformance) {
gamePerformance.validate();
}
if (null == maintainInfo) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
maintainInfo.validate();
}
}
(3) 范畴层 VS 事务层
范畴层和事务层都包括事务,二者不是代替联系,而是互补联系。事务层能够愈加灵活组合不同范畴事务,并且能够添加流控、监控、日志、权限,分布式锁等操控,相较于范畴层功用更为丰厚。
2.3.2 项目结构
代码层分为两个范畴:
- player:运动员
- game:竞赛
每个范畴具有三个子包:
- domain:范畴目标
- event:范畴工作
- vo:值目标
user-demo-service-domain
-/src/main/java
-base
-domain
-BaseDomain.java
-event
-BaseEvent.java
-vo
-BaseVO.java
-MaintainCreateVO.java
-MaintainUpdateVO.java
-player
-domain
-PlayerCreateDomain.java
-PlayerUpdateDomain.java
-PlayerQueryResultDomain.java
-event
-PlayerUpdateEvent.java
-vo
-GamePerformanceVO.java
-game
-domain
-GameCreateDomain.java
-GameUpdateDomain.java
-GameQueryResultDomain.java
-event
-GameUpdateEvent.java
-vo
-GameSubstitutionVO.java
2.3.3 本项目间依靠联系
domain依靠本项目两个模块:
- util
- client
之所以依靠client模块是由于范畴目标聚合了事务校验,以下信息需求露出至外部:
- BizException
- ErrorCodeBizEnum
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-util</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-client</artifactId>
</dependency>
2.3.4 中心代码
以运动员修正范畴目标为例:
// 运动员修正范畴目标
public class PlayerUpdateDomain extends BaseDomain implements BizValidator {
private String playerId;
private String playerName;
private Integer height;
private Integer weight;
private String updator;
private Date updatetime;
private GamePerformanceVO gamePerformance;
private MaintainUpdateVO maintainInfo;
@Override
public void validate() {
if (StringUtils.isEmpty(playerId)) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (StringUtils.isEmpty(playerName)) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == height) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (height > 300) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == weight) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null != gamePerformance) {
gamePerformance.validate();
}
if (null == maintainInfo) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
maintainInfo.validate();
}
}
// 竞赛体现值目标
public class GamePerformanceVO implements BizValidator {
// 跑动间隔
private Double runDistance;
// 传球成功率
private Double passSuccess;
// 进球数
private Integer scoreNum;
@Override
public void validate() {
if (null == runDistance) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == passSuccess) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (Double.compare(passSuccess, 100) > 0) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == runDistance) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == scoreNum) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
}
}
// 修正人值目标
public class MaintainUpdateVO implements BizValidator {
// 修正人
private String updator;
// 修正时刻
private Date updateTime;
@Override
public void validate() {
if (null == updator) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
if (null == updateTime) {
throw new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT);
}
}
}
2.4 service
2.4.1 项目结构
user-demo-service-service
-/src/main/java
-player
-adapter
-PlayerServiceAdapter.java
-event
-PlayerMessageSender.java
-service
-PlayerService.java
-game
-adapter
-GameServiceAdapter.java
-event
-GameMessageSender.java
-service
-GameService.java
2.4.2 本项目间依靠联系
service依靠本项目四个模块:
- util
- domain
- integration
- infrastructure
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-domain</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-infrastructure</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-util</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-integration</artifactId>
</dependency>
2.4.3 中心代码
以运动员修正服务为例:
// 运动员服务
public class PlayerService {
@Resource
private PlayerEntityMapper playerEntityMapper;
@Resource
private PlayerMessageSender playerMessageSender;
@Resource
private PlayerServiceAdapter playerServiceAdapter;
public boolean updatePlayer(PlayerUpdateDomain player) {
AssertUtil.notNull(player, new BizException(ErrorCodeBizEnum.ILLEGAL_ARGUMENT));
player.validate();
PlayerEntity entity = playerServiceAdapter.convertUpdate(player);
playerEntityMapper.updateById(entity);
playerMessageSender.sendPlayerUpdatemessage(player);
return true;
}
}
// 运动员音讯服务
public class PlayerMessageSender {
@Resource
private PlayerServiceAdapter playerServiceAdapter;
public boolean sendPlayerUpdatemessage(PlayerUpdateDomain domain) {
PlayerUpdateEvent event = playerServiceAdapter.convertUpdateEvent(domain);
log.info("sendPlayerUpdatemessage event={}", event);
return true;
}
}
// 服务适配器
public class PlayerServiceAdapter {
// domain -> entity
public PlayerEntity convertUpdate(PlayerUpdateDomain domain) {
PlayerEntity player = new PlayerEntity();
player.setPlayerId(domain.getPlayerId());
player.setPlayerName(domain.getPlayerName());
player.setWeight(domain.getWeight());
player.setHeight(domain.getHeight());
if (null != domain.getGamePerformance()) {
player.setGamePerformance(JacksonUtil.bean2Json(domain.getGamePerformance()));
}
String updator = domain.getMaintainInfo().getUpdator();
Date updateTime = domain.getMaintainInfo().getUpdateTime();
player.setUpdator(updator);
player.setUpdateTime(updateTime);
return player;
}
// domain -> event
public PlayerUpdateEvent convertUpdateEvent(PlayerUpdateDomain domain) {
PlayerUpdateEvent event = new PlayerUpdateEvent();
event.setPlayerUpdateDomain(domain);
event.setMessageId(UUID.randomUUID().toString());
event.setMessageId(PlayerMessageType.UPDATE.getMsg());
return event;
}
}
2.5 intergration
本项目可能会依靠外部服务,那么将外部DTO转换为本项目能够了解的目标,需求在本层处理。
2.5.1 项目结构
假定本项目调用了用户中心服务:
user-demo-service-intergration
-/src/main/java
-user
-adapter
-UserClientAdapter.java
-proxy
-UserClientProxy.java
2.5.2 本项目间依靠联系
intergration依靠本项目两个模块:
- util
- domain
之所以依靠domain模块,是由于本层需求将外部DTO转换为本项目能够了解的目标,这些目标就放在domain模块。
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-domain</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-util</artifactId>
</dependency>
2.5.3 中心代码
现在咱们将外部目标UserClientDTO
转换为本项目范畴目标UserInfoDomain
(1) 外部服务
// 外部目标
public class UserInfoClientDTO implements Serializable {
private String id;
private String name;
private Date createTime;
private Date updateTime;
private String mobile;
private String cityCode;
private String addressDetail;
}
// 外部服务
public class UserClientService {
// RPC模拟
public UserInfoClientDTO getUserInfo(String userId) {
UserInfoClientDTO userInfo = new UserInfoClientDTO();
userInfo.setId(userId);
userInfo.setName(userId);
userInfo.setCreateTime(DateUtil.now());
userInfo.setUpdateTime(DateUtil.now());
userInfo.setMobile("test-mobile");
userInfo.setCityCode("test-city-code");
userInfo.setAddressDetail("test-address-detail");
return userInfo;
}
}
(2) 本项目范畴目标
domain模块新增user范畴:
user-demo-service-domain
-/src/main/java
-user
-domain
-UserDomain.java
-vo
-UserAddressVO.java
-UserContactVO.java
user范畴目标代码:
// 用户范畴
public class UserInfoDomain extends BaseDomain {
private UserContactVO contactInfo;
private UserAddressVO addressInfo;
}
// 地址值目标
public class UserAddressVO extends BaseVO {
private String cityCode;
private String addressDetail;
}
// 联系方式值目标
public class UserContactVO extends BaseVO {
private String mobile;
}
(3) 适配器
public class UserClientAdapter {
// third dto -> domain
public UserInfoDomain convertUserDomain(UserInfoClientDTO userInfo) {
UserInfoDomain userDomain = new UserInfoDomain();
UserContactVO contactVO = new UserContactVO();
contactVO.setMobile(userInfo.getMobile());
userDomain.setContactInfo(contactVO);
UserAddressVO addressVO = new UserAddressVO();
addressVO.setCityCode(userInfo.getCityCode());
addressVO.setAddressDetail(userInfo.getAddressDetail());
userDomain.setAddressInfo(addressVO);
return userDomain;
}
}
(4) 调用外部服务
public class UserClientProxy {
@Resource
private UserClientService userClientService;
@Resource
private UserClientAdapter userClientAdapter;
public UserInfoDomain getUserInfo(String userId) {
UserInfoClientDTO user = userClientService.getUserInfo(userId);
UserInfoDomain result = userClientAdapter.convertUserDomain(user);
return result;
}
}
2.6 facade + client
规划形式中有一种Facade形式,称为门面形式或许外观形式。这种形式供给一个简练对外语义,屏蔽内部体系复杂性。
client承载数据对外传输目标DTO,facade承载对外服务,这两层有必要满意最小常识准则,无关信息不必对外透出。
这样做有两个长处:
- 简练性:对外服务语义明确简练
- 安全性:敏感字段不能对外透出
2.6.1 项目结构
(1) client
user-demo-service-client
-/src/main/java
-base
-dto
-BaseDTO.java
-error
-BizException.java
-BizErrorCode.java
-event
-BaseEventDTO.java
-result
-ResultDTO.java
-player
-dto
-PlayerCreateDTO.java
-PlayerQueryResultDTO.java
-PlayerUpdateDTO.java
-enums
-PlayerMessageTypeEnum.java
-event
-PlayerUpdateEventDTO.java
-service
-PlayerClientService.java
(2) facade
user-demo-service-facade
-/src/main/java
-player
-adapter
-PlayerFacadeAdapter.java
-impl
-PlayerClientServiceImpl.java
-game
-adapter
-GameFacadeAdapter.java
-impl
-GameClientServiceImpl.java
2.6.2 本项目间依靠联系
client不依靠本项目其它模块,这一点非常重要,由于client会被外部引证,有必要确保这一层简练和安全。
facade依靠本项目三个模块:
- domain
- client
- service
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-domain</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-client</artifactId>
</dependency>
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-service</artifactId>
</dependency>
2.6.3 中心代码
(1) DTO
以查询运动员信息为例,查询成果DTO只封装最要害字段,例如运动员ID、创立时刻、修正时刻等事务不强字段就无须透出:
public class PlayerQueryResultDTO implements Serializable {
private String playerName;
private Integer height;
private Integer weight;
private GamePerformanceDTO gamePerformanceDTO;
}
(2) 客户端服务
public interface PlayerClientService {
public ResultDTO<PlayerQueryResultDTO> queryById(String playerId);
}
(3) 适配器
public class PlayerFacadeAdapter {
// domain -> dto
public PlayerQueryResultDTO convertQuery(PlayerQueryResultDomain domain) {
if (null == domain) {
return null;
}
PlayerQueryResultDTO result = new PlayerQueryResultDTO();
result.setPlayerId(domain.getPlayerId());
result.setPlayerName(domain.getPlayerName());
result.setHeight(domain.getHeight());
result.setWeight(domain.getWeight());
if (null != domain.getGamePerformance()) {
GamePerformanceDTO performance = convertGamePerformance(domain.getGamePerformance());
result.setGamePerformanceDTO(performance);
}
return result;
}
}
(4) 服务完成
public class PlayerClientServiceImpl implements PlayerClientService {
@Resource
private PlayerService playerService;
@Resource
private PlayerFacadeAdapter playerFacadeAdapter;
@Override
public ResultDTO<PlayerQueryResultDTO> queryById(String playerId) {
PlayerQueryResultDomain resultDomain = playerService.queryPlayerById(playerId);
if (null == resultDomain) {
return ResultCommonDTO.success();
}
PlayerQueryResultDTO result = playerFacadeAdapter.convertQuery(resultDomain);
return ResultCommonDTO.success(result);
}
}
2.7 controller
facade服务完成能够作为RPC供给服务,controller则作为本项目HTTP接口供给服务,供前端调用。
controller需求注意HTTP相关特性,敏感信息例如登陆用户ID不能依靠前端传递,登陆后前端会在恳求头带一个登陆用户信息,服务端需求从恳求头中获取并解析。
2.7.1 项目结构
user-demo-service-controller
-/src/main/java
-config
-CharsetConfig.java
-controller
-player
-PlayerController.java
-game
-GameController.java
2.7.2 本项目依靠联系
controller依靠本项目一个模块:
- facade
根据依靠传递原理一起依靠以下模块:
- domain
- client
- service
<dependency>
<groupId>com.test.javafront</groupId>
<artifactId>user-demo-service-facade</artifactId>
</dependency>
2.7.3 中心代码
@RestController
@RequestMapping("/player")
public class PlayerController {
@Resource
private PlayerClientService playerClientService;
@PostMapping("/add")
public ResultDTO<Boolean> add(@RequestHeader("test-login-info") String loginUserId, @RequestBody PlayerCreateDTO dto) {
dto.setCreator(loginUserId);
ResultCommonDTO<Boolean> resultDTO = playerClientService.addPlayer(dto);
return resultDTO;
}
@PostMapping("/update")
public ResultDTO<Boolean> update(@RequestHeader("test-login-info") String loginUserId, @RequestBody PlayerUpdateDTO dto) {
dto.setUpdator(loginUserId);
ResultCommonDTO<Boolean> resultDTO = playerClientService.updatePlayer(dto);
return resultDTO;
}
@GetMapping("/{playerId}/query")
public ResultDTO<PlayerQueryResultDTO> queryById(@RequestHeader("test-login-info") String loginUserId, @PathVariable("playerId") String playerId) {
ResultCommonDTO<PlayerQueryResultDTO> resultDTO = playerClientService.queryById(playerId);
return resultDTO;
}
}
2.8 boot
boot作为发动层,只要发动进口代码
2.8.1 项目结构
一切模块代码均有必要属于com.user.demo.service子途径
user-demo-service-boot
-/src/main/java
-com.user.demo.service
-MainApplication.java
2.8.2 本项目间依靠
boot引证本项目一切模块
- util
- integration
- infrastructure
- service
- domain
- facade
- controller
- client
2.8.3 中心代码
@MapperScan("com.user.demo.service.infrastructure.*.mapper")
@SpringBootApplication
public class MainApplication {
public static void main(final String[] args) {
SpringApplication.run(MainApplication.class, args);
}
}
3 文章总结
咱们再次回顾分层五个思考维度:
(1) 单一
每层只处理一类工作,例如util只承载东西目标,integration只处理外部服务,每层责任单一且明晰
(2) 降噪
如无必要无增实体,例如查询成果DTO只透出最要害字段,例如运动员ID、创立时刻、修正时刻等事务不强字段无须透出
(3) 适配
service、facade、intergration层都存在适配器,翻译信息为本层或许基层能够了解的信息
(4) 事务
事务目标能够经过充血模型聚合事务,例如在事务目标中聚合事务校验逻辑
(5) 数据
数据目标要纯洁,例如经过string类型保存竞赛体现,数据层无需解析
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