＜Spring Boot＞开发基于三层架构设计：Dao层、Service层、Controller层及案例一

三层架构设计：基于Spring Boot开发要使用三层架构：

数据访问层（Dao）、业务逻辑层（Service）、控制层（Control-ler）

（1）数据访问层（Dao）：Dao层是最底层的设计，用户操作数据库。通过MyBatis持久化实现接口开发，XML文件。Dao层的设计步骤：1、在数据库中生成数据库表 2通过XML文件实现数据库的映射和操作。

（2）业务逻辑层（Service）：Service层是中间层，在Dao层和Controller层之间进行逻辑处理工作。考虑到程序的耦合度问题，为了降低各个模块的关联，每个接口都封装有各自的业务处理方法。

（3）控制层（Controller）：Controller是第三层，通过调用Service层，与前端页面交互。

CRUD案例如下：

Controller层：


@Slf4j
@RestController
@RequestMapping("/xxxList")
public class XxxListController {@Autowiredprivate XxxListService xxxListService;/*** 查询：配置* 权限-管理员** @param param* @return*/@PostMapping(value = "/selectXxxConfig")@AuthInterceptor("mag:getXxx:selectXxxConfig")public Result selectXxxConfig(@RequestBody String param) {try {Map<String, Object> paramMap = JsonUtils.readValue(param, Map.class);return Result.success().result(xxxListService.selectXxxConfig(paramMap));} catch (Exception e) {log.error("XxxListController selectXxxConfig is error===:" + e.getMessage(), e);return Result.failure("查询失败");}}/*** 新增/修改：配置* 权限-管理员** @param param* @return*/@PostMapping(value = "/addOrModifyXxxConfig")@AuthInterceptor("mag:getXxx:addOrModifyXxxConfig")public Result addOrModifyXxxConfig(@RequestBody String param) {try {Map<String, Object> paramMap = JsonUtils.readValue(param, Map.class);xxxListService.addOrModifyXxxConfig(paramMap);} catch (Exception e) {log.error("XxxListController addOrModifyXxxConfig is error===:" + e.getMessage(), e);return Result.failure("更新失败");}return Result.success().result(null);}/*** 删除：表单数据* 权限-管理员** @param param* @return*/@PostMapping(value = "/deleteData")@AuthInterceptor("mag:getXxx:deleteData")public Result deleteFormData(@RequestBody String param) {try {Map<String, Object> paramMap = JsonUtils.readValue(param, Map.class);xxxListService.deleteData(paramMap);} catch (Exception e) {log.error("XxxListController deleteData is error===:" + e.getMessage(), e);return Result.failure("数据删除失败");}return Result.success().result(null);}}

Servicer层：

	
public interface XxxListService {//查询：配置PageInfo<Map<String, Object>> selectXxxConfig(Map<String, Object> paramMap);//新增/修改：配置Result addOrModifyXxxConfig(Map<String, Object> paramMap);//删除：表单数据void deleteData(Map<String, Object> paramMap);}

ServicerImpl层：

	
@Slf4j
@Service
public class XxxListServiceImpl implements XxxListService {@Autowiredprivate XxxListMapper xxxListMapper;/** 查询：配置**/@Overridepublic PageInfo<Map<String, Object>> selectXxxConfig(Map<String, Object> paramMap) {；CommonUtil.getPageHelper(paramMap);List<Map<String, Object>> list = xxxListMapper.selectXxxConfig(paramMap);PageInfo<Map<String, Object>> result = new PageInfo<>(list);return result;}	/** 新增/修改：配置**/@Overridepublic Result addOrModifyXxxConfig(Map<String, Object> paramMap) {String addOrModify = String.valueOf(paramMap.get("addOrModify"));if(addOrModify.equals("add")){paramMap.remove("addOrModify");List<Map<String,String>> reg = getRegionList();  // 获取地域信息List<Map<String,String>> list = xxxListMapper.selectXxxRegAll();  // 查询本数据库地域信息Iterator<Map<String, String>> iterator = reg.iterator();while (iterator.hasNext()){Map<String, String> next = iterator.next();String name = String.valueOf(next.get("name"));String code = String.valueOf(next.get("code"));next.put("isEnable","1");Iterator<Map<String, String>> iterator2 = list.iterator();while (iterator2.hasNext()){Map<String, String> next2 = iterator2.next();String regionName = String.valueOf(next2.get("name"));String RegionCode = String.valueOf(next2.get("code"));if(name.equals(regionName) && code.equals(RegionCode)){iterator.remove();}}}if(reg.size() > 0){xxxListMapper.addXxxConfig(reg);}}else if(addOrModify.equals("modify")){  // "isEnableVal",1:"使用",2:"停用"String sortId = String.valueOf(paramMap.get("sortId"));String isEnable = String.valueOf(paramMap.get("isEnable"));if(!sortId.equals("null") && !sortId.equals("") || !isEnable.equals("null") && !isEnable.equals("")){xxxListMapper.modifyXxxConfig(paramMap);}}return Result.success().result(null);}/** 删除：表单数据**/@Overridepublic void deleteData(Map<String, Object> paramMap) {xxxListMapper.deleteData(paramMap);}}

Mapper层（又称Dao层）：

	
@Mapper
public interface XxxListMapper {//查询：所有配置(先查所有配置)List<Map<String, String>> selectXxxRegAll();//查询：配置List<Map<String, Object>> selectXxxConfig(Map<String, Object> paramMap);//新增：配置void addXxxConfig(List<Map<String, String>> paramList);//修改：配置void modifyXxxConfig(Map<String, Object> paramMap);//删除：表单数据void deleteData(Map<String, Object> paramMap);}

Mapper.xml层（MyBatis层）：

	
<?xml version="1.0" encoding="UTF-8"?>
<!--约束条件-->
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--命名空间：找到所在的XxxListMapper接口的位置-->
<mapper namespace="com.itheima.service.mapper.XxxListMapper"><!--sql语句代码--><!-- 查询：所有配置(先查所有配置) --><select id="selectXxxRegAll" resultType="map">SELECT *FROM xxx_region_list_dic where 1 = 1</select><!-- 查询：配置 --><select id="selectXxxConfig" parameterType="map" resultType="map">SELECT *FROM xxx_region_list_dic where 1 = 1<!-- 分页字段 --><if test="null != processResult">and processResult = #{processResult}</if><if test="null != name and '' != name">and name = #{name}</if><if test="null != code and '' != code">and code = #{code}</if><if test="null != isEnable and '' != isEnable">and isEnable = #{isEnable}</if>order by sortId</select><!-- 新增：配置 --><insert id="addXxxConfig" parameterType="java.util.List"><foreach collection="list" item="region" index="index" separator=";">INSERT IGNORE INTO xxx_region_list_dic<foreach collection="region.entrySet()" index="key" separator="," open="(" close=")">${key}</foreach>VALUES<foreach collection="region.entrySet()" item="value" separator="," open="(" close=")">#{value}</foreach></foreach></insert><!-- 修改：配置 --><update id="modifyXxxConfig" parameterType="map">update xxx_region_list_dic<set><if test = "null != sortId and '' != sortId">sortId = #{sortId},</if><if test = "null != isEnable and '' != isEnable">isEnable = #{isEnable}</if></set>where<if test = "null != seqId and '' != seqId">seqId = #{seqId}</if></update><!-- 删除：表单数据 --><delete id="deleteData">delete from xxx_form_data_listwhere<if test = "null != No and '' != No">No = #{No}</if></delete></mapper>