1.创建项目

1.创建项目

创建spring initializar项目，引入spring web模块

2.在pom.xml文件中引入依赖

引入spring boot、热部署、MySQL、mybatis、log4j

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  3.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  4.     <modelVersion>4.0.0</modelVersion>
  5.     <parent>
  6.         <groupId>org.springframework.boot</groupId>
  7.         <artifactId>spring-boot-starter-parent</artifactId>
  8.         <version>2.2.5.RELEASE</version>
  9.         <relativePath/> <!-- lookup parent from repository -->
  10.     </parent>
  11.     <groupId>com.huang</groupId>
  12.     <artifactId>parking-lot-server</artifactId>
  13.     <version>0.0.1-SNAPSHOT</version>
  14.     <name>parking-lot-server</name>
  15.     <description>Demo project for Spring Boot</description>
  17.     <properties>
  18.         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  19.         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
  20.         <java.version>1.8</java.version>
  21.     </properties>
  23.     <dependencies>
  24.         <!--spring boot-->
  25.         <dependency>
  26.             <groupId>org.springframework.boot</groupId>
  27.             <artifactId>spring-boot-starter-web</artifactId>
  28.         </dependency>
  29.         <!--热部署-->
  30.         <dependency>
  31.             <groupId>org.springframework.boot</groupId>
  32.             <artifactId>spring-boot-devtools</artifactId>
  33.             <optional>true</optional>
  34.         </dependency>
  35.         <!--test-->
  36.         <dependency>
  37.             <groupId>org.springframework.boot</groupId>
  38.             <artifactId>spring-boot-starter-test</artifactId>
  39.             <scope>test</scope>
  40.             <exclusions>
  41.                 <exclusion>
  42.                     <groupId>org.junit.vintage</groupId>
  43.                     <artifactId>junit-vintage-engine</artifactId>
  44.                 </exclusion>
  45.             </exclusions>
  46.         </dependency>
  48.         <!--mysql-->
  49.         <dependency>
  50.             <groupId>mysql</groupId>
  51.             <artifactId>mysql-connector-java</artifactId>
  52.         </dependency>
  53.         <!--mybatisPlus-->
  54.         <dependency>
  55.             <groupId>com.baomidou</groupId>
  56.             <artifactId>mybatis-plus-boot-starter</artifactId>
  57.             <version>3.5.1</version>
  58.         </dependency>
  59.         <!--druid 数据库连接池-->
  60.         <dependency>
  61.             <groupId>com.alibaba</groupId>
  62.             <artifactId>druid</artifactId>
  63.             <version>1.1.16</version>
  64.         </dependency>
  66.     </dependencies>
  68.     <build>
  69.         <plugins>
  70.             <plugin>
  71.                 <groupId>org.springframework.boot</groupId>
  72.                 <artifactId>spring-boot-maven-plugin</artifactId>
  73.             </plugin>
  74.         </plugins>
  75.     </build>
  76. </project>

3.application.yml配置方式

3.1 静态指定，就是运行项目前指定使用的环境

  1. server:
  2.   port: 9988
  3. spring:
  4.   profiles:
  5.     active: dev
  7. ---
  9. server:
  10.   port: 9981
  11. spring:
  12.   profiles: prod

注意每个环境之间使用—-分隔（注意是三个—-分隔），默认第一个是主环境。可以在默认环境指定使用其他环境。

3.2 动态切换

通过运行参数指定环境

  • Idea : 在application主运行类鼠标右键 -》 Edit 项目名application -》Program arguments -》输入 —spring.profiles.active=环境名，如下图

image.png

  • 通过maven的打jar包形式把项目打包，然后cmd运行，输入 java -jar 项目名.jar spring.profiles.active=环境名

通过vm参数指定环境
vm参数也在上图中，就是上图的VM options ，然后输入：-Dspring.profiles.active=环境名，注意开头是-D。

4..在application-dev.yml下添加配置

  1. spring:
  2.   datasource:
  3.     driver-class-name: com.mysql.cj.jdbc.Driver
  4.     url: "jdbc:mysql://127.0.0.1:3306/parkingLot?serverTimezone=UTC"
  5.     username: "root"
  6.     password: "root"

2.配置MybatisPlus

1.添加依赖

  1. <!--mybatisPlus-->
  2. <dependency>
  3.     <groupId>com.baomidou</groupId>
  4.     <artifactId>mybatis-plus-boot-starter</artifactId>
  5.     <version>3.5.1</version>
  6. </dependency>

2.在application-dev.yml下添加配置

  1. mybatis-plus:
  2.   # 如果是放在src/main/java目录下 classpath:/com/yourpackage/*/mapper/*Mapper.xml
  3.   # 如果是放在resource目录 classpath:/mapper/*Mapper.xml
  4.   mapper-locations: classpath:mybatis/mappers/*Mapper.xml
  5.   #实体扫描，多个package用逗号或者分号分隔
  6.   typeAliasesPackage: cn.saytime.model
  7.   global-config:
  8.     #主键类型  0:"数据库ID自增", 1:"用户输入ID",2:"全局唯一ID (数字类型唯一ID)", 3:"全局唯一ID UUID";
  9.     id-type: 0
  10.     #字段策略 0:"忽略判断",1:"非 NULL 判断"),2:"非空判断"
  11.     field-strategy: 1
  12.     #驼峰下划线转换
  13.     #db-column-underline: true
  14.     #刷新mapper 调试神器
  15.     #refresh-mapper: true
  16.     #数据库大写下划线转换
  17.     #capital-mode: true
  18.     # Sequence序列接口实现类配置
  19.     #key-generator: com.baomidou.mybatisplus.incrementer.OracleKeyGenerator
  20.     #逻辑删除配置（下面3个配置）
  21.     #logic-delete-value: 1
  22.     #logic-not-delete-value: 0
  23.     #sql-injector: com.baomidou.mybatisplus.mapper.LogicSqlInjector
  24.     #自定义填充策略接口实现
  25.     #meta-object-handler: com.baomidou.springboot.MyMetaObjectHandler
  26.   configuration:
  27.     map-underscore-to-camel-case: true
  28.     cache-enabled: false
  29.     #配置JdbcTypeForNull
  30.     jdbc-type-for-null: 'null'

3.配置Druid数据源

1.添加依赖

  1. <!--druid 数据库连接池-->
  2. <dependency>
  3.     <groupId>com.alibaba</groupId>
  4.     <artifactId>druid</artifactId>
  5.     <version>1.1.16</version>
  6. </dependency>

2.在application-dev.yml下添加配置

  1. spring:
  2.   datasource:
  3.     driver-class-name: com.mysql.cj.jdbc.Driver
  4.     url: "jdbc:mysql://127.0.0.1:3306/parkingLot?serverTimezone=UTC"
  5.     username: "root"
  6.     password: "root"
  7.     #指定数据源，不用默认的数据源
  8.     type: com.alibaba.druid.pool.DruidDataSource
  10.     # 数据源其他配置
  11.     initialSize: 5
  12.     minIdle: 5
  13.     maxActive: 20
  14.     maxWait: 60000
  15.     timeBetweenEvictionRunsMillis: 60000
  16.     minEvictableIdleTimeMillis: 300000
  17.     validationQuery: SELECT 1 FROM DUAL
  18.     testWhileIdle: true
  19.     testOnBorrow: false
  20.     testOnReturn: false
  21.     poolPreparedStatements: true
  22.     # 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙
  23.     filters: stat,wall,log4j
  24.     maxPoolPreparedStatementPerConnectionSize: 20
  25.     useGlobalDataSourceStat: true
  26.     connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=500

多数据源配置

  1. spring:
  2.   datasource:
  3.     master:
  4.       jdbc-url: jdbc:mysql://192.168.102.31:3306/test
  5.       username: root
  6.       password: 123456
  7.       driver-class-name: com.mysql.jdbc.Driver
  8.     slave1:
  9.       jdbc-url: jdbc:mysql://192.168.102.56:3306/test
  10.       username: pig   # 只读账户
  11.       password: 123456
  12.       driver-class-name: com.mysql.jdbc.Driver
  13.     slave2:
  14.       jdbc-url: jdbc:mysql://192.168.102.36:3306/test
  15.       username: pig   # 只读账户
  16.       password: 123456
  17.       driver-class-name: com.mysql.jdbc.Driver

3.配置Druid配置文件

  1. package com.example.config;
  3. import com.alibaba.druid.pool.DruidDataSource;
  4. import com.alibaba.druid.support.http.StatViewServlet;
  5. import com.alibaba.druid.support.http.WebStatFilter;
  6. import org.springframework.boot.context.properties.ConfigurationProperties;
  7. import org.springframework.boot.web.servl
  8. et.FilterRegistrationBean;
  9. import org.springframework.boot.web.servlet.ServletRegistrationBean;
  10. import org.springframework.context.annotation.Bean;
  11. import org.springframework.context.annotation.Configuration;
  13. import javax.sql.DataSource;
  14. import java.util.Arrays;
  15. import java.util.HashMap;
  16. import java.util.Map;
  18. @Configuration
  19. public class DruidConfig {
  21.     @ConfigurationProperties(prefix = "spring.datasource")
  22.     @Bean
  23.     public DataSource druid(){
  24.         return new DruidDataSource();
  25.     }
  28.     /**
  29.     * 配置Druid的监控
  30.     * 1.配置一个管理后台的Servlet
  31.     * @return
  32.     */
  33.     @Bean
  34.     public ServletRegistrationBean statViewServlet(){
  35.         ServletRegistrationBean bean = new ServletRegistrationBean(new StatViewServlet(), "/druid/*");
  36.         Map<String,String> initParams = new HashMap<>();
  37.         initParams.put("loginUsername","admin");
  38.         initParams.put("loginPassword","123456");
  39.         //默认就是允许所有访问
  40.         initParams.put("allow","");
  41.         initParams.put("deny","192.168.15.21");
  42.         bean.setInitParameters(initParams);
  43.         return bean;
  44.     }
  47.     /**
  48.     * 2、配置一个web监控的filter
  49.     * @return
  50.     */
  51.     @Bean
  52.     public FilterRegistrationBean webStatFilter(){
  53.         FilterRegistrationBean bean = new FilterRegistrationBean();
  54.         bean.setFilter(new WebStatFilter());
  55.         Map<String,String> initParams = new HashMap<>();
  56.         initParams.put("exclusions","*.js,*.css,/druid/*");
  57.         bean.setInitParameters(initParams);
  58.         bean.setUrlPatterns(Arrays.asList("/*"));
  59.         return  bean;
  60.     }
  62. }

多数据源配置

  1. import com.alibaba.druid.pool.DruidDataSource;
  2. import org.apache.ibatis.session.SqlSessionFactory;
  3. import org.mybatis.spring.SqlSessionFactoryBean;
  4. import org.mybatis.spring.annotation.MapperScan;
  5. import org.springframework.beans.factory.annotation.Qualifier;
  6. import org.springframework.beans.factory.annotation.Value;
  7. import org.springframework.boot.context.properties.ConfigurationProperties;
  8. import org.springframework.context.annotation.Bean;
  9. import org.springframework.context.annotation.Configuration;
  10. import org.springframework.context.annotation.Primary;
  11. import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
  12. import org.springframework.jdbc.datasource.DataSourceTransactionManager;
  14. import javax.sql.DataSource;
  16. @Configuration
  17. // 扫描 Mapper 接口并容器管理
  18. @MapperScan(basePackages = MasterDataSourceConfig.PACKAGE, sqlSessionFactoryRef = "masterSqlSessionFactory")
  19. public class MasterDataSourceConfig {
  21.     // 精确到 master 目录，以便跟其他数据源隔离
  22.     static final String PACKAGE = "org.spring.springboot.dao.master";
  23.     static final String MAPPER_LOCATION = "classpath:mapper/master/*.xml";
  25.     @Value("${master.datasource.url}")
  26.     private String url;
  28.     @Value("${master.datasource.username}")
  29.     private String user;
  31.     @Value("${master.datasource.password}")
  32.     private String password;
  34.     @Value("${master.datasource.driverClassName}")
  35.     private String driverClass;
  37.     @Bean(name = "masterDataSource")
  38.     @Primary
  39.     public DataSource masterDataSource() {
  40.         DruidDataSource dataSource = new DruidDataSource();
  41.         dataSource.setDriverClassName(driverClass);
  42.         dataSource.setUrl(url);
  43.         dataSource.setUsername(user);
  44.         dataSource.setPassword(password);
  45.         return dataSource;
  46.     }
  48.     @Bean(name = "masterTransactionManager")
  49.     @Primary
  50.     public DataSourceTransactionManager masterTransactionManager() {
  51.         return new DataSourceTransactionManager(masterDataSource());
  52.     }
  54.     @Bean(name = "masterSqlSessionFactory")
  55.     @Primary
  56.     public SqlSessionFactory masterSqlSessionFactory(@Qualifier("masterDataSource") DataSource masterDataSource)
  57.             throws Exception {
  58.         final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
  59.         sessionFactory.setDataSource(masterDataSource);
  60.         sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver()
  61.                 .getResources(MasterDataSourceConfig.MAPPER_LOCATION));
  62.         return sessionFactory.getObject();
  63.     }
  64. }
  1. import com.alibaba.druid.pool.DruidDataSource;
  2. import org.apache.ibatis.session.SqlSessionFactory;
  3. import org.mybatis.spring.SqlSessionFactoryBean;
  4. import org.mybatis.spring.annotation.MapperScan;
  5. import org.springframework.beans.factory.annotation.Qualifier;
  6. import org.springframework.beans.factory.annotation.Value;
  7. import org.springframework.context.annotation.Bean;
  8. import org.springframework.context.annotation.Configuration;
  9. import org.springframework.context.annotation.Primary;
  10. import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
  11. import org.springframework.jdbc.datasource.DataSourceTransactionManager;
  13. import javax.sql.DataSource;
  15. @Configuration
  16. // 扫描 Mapper 接口并容器管理
  17. @MapperScan(basePackages = ClusterDataSourceConfig.PACKAGE, sqlSessionFactoryRef = "clusterSqlSessionFactory")
  18. public class ClusterDataSourceConfig {
  20.     // 精确到 cluster 目录，以便跟其他数据源隔离
  21.     static final String PACKAGE = "org.spring.springboot.dao.cluster";
  22.     static final String MAPPER_LOCATION = "classpath:mapper/cluster/*.xml";
  24.     @Value("${cluster.datasource.url}")
  25.     private String url;
  27.     @Value("${cluster.datasource.username}")
  28.     private String user;
  30.     @Value("${cluster.datasource.password}")
  31.     private String password;
  33.     @Value("${cluster.datasource.driverClassName}")
  34.     private String driverClass;
  36.     @Bean(name = "clusterDataSource")
  37.     public DataSource clusterDataSource() {
  38.         DruidDataSource dataSource = new DruidDataSource();
  39.         dataSource.setDriverClassName(driverClass);
  40.         dataSource.setUrl(url);
  41.         dataSource.setUsername(user);
  42.         dataSource.setPassword(password);
  43.         return dataSource;
  44.     }
  46.     @Bean(name = "clusterTransactionManager")
  47.     public DataSourceTransactionManager clusterTransactionManager() {
  48.         return new DataSourceTransactionManager(clusterDataSource());
  49.     }
  51.     @Bean(name = "clusterSqlSessionFactory")
  52.     public SqlSessionFactory clusterSqlSessionFactory(@Qualifier("clusterDataSource") DataSource clusterDataSource)
  53.             throws Exception {
  54.         final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
  55.         sessionFactory.setDataSource(clusterDataSource);
  56.         sessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver()
  57.                 .getResources(ClusterDataSourceConfig.MAPPER_LOCATION));
  58.         return sessionFactory.getObject();
  59.     }
  60. }

4.测试获得的数据源类型

  1. @SpringBootTest
  2. class SpringBoot06DataJdbcApplicationTests {
  4.     @Autowired
  5.     DataSource dataSource;
  7.     @Test
  8.     void contextLoads() throws SQLException {
  9.         System.out.println("获取的数据源===="+dataSource.getClass());
  11.         Connection connection = dataSource.getConnection();
  12.         System.out.println("获取的连接==="+connection);
  13.         connection.close();
  14.     }
  16. }

5.登录

可登录localhost:9988/druid/login.html

可能遇到的问题

在启动时报错

  1. ***************************
  2. APPLICATION FAILED TO START
  3. ***************************
  5. Description:
  7. Failed to bind properties under 'spring.datasource' to javax.sql.DataSource:
  9.     Property: spring.datasource.filters
  10.     Value: stat,wall,log4j
  11.     Origin: class path resource [application.yml]:24:14
  12.     Reason: org.apache.log4j.Logger
  14. Action:
  16. Update your application's configuration

根据报错提示在配置文件的24行，查看配置文件，该行代码是 filters: stat,wall,log4j
看报错原因Reason: org.apache.log4j.Logger，于是猜想少了log4j的相关依赖，在pom中引入相关依赖

  1. <!-- https://mvnrepository.com/artifact/log4j/log4j -->
  2.         <dependency>
  3.             <groupId>log4j</groupId>
  4.             <artifactId>log4j</artifactId>
  5.             <version>1.2.17</version>
  6.         </dependency>

4.构建三层架构

如下图构建
image.png

1.实体类

entity类

  1. package com.huang.parkinglotserver.entity;
  3. import com.baomidou.mybatisplus.annotation.TableField;
  4. import com.baomidou.mybatisplus.annotation.TableId;
  5. import com.baomidou.mybatisplus.annotation.TableName;
  7. @TableName(value = "user")
  8. public class User {
  10.     @TableId(value = "id")
  11.     private String id;
  13.     @TableField(value = "user_name")
  14.     private String userName;
  16.     @TableField(value = "user_password")
  17.     private String userPassword;
  19.     @TableField(value = "user_authority")
  20.     private String userAuthority;
  22.     //get、set方法
  23.     }

前端传输数据，AO接收

  1. package com.huang.parkinglotserver.ao;
  2. public class UserAo {
  4.     private String userName;
  5.     private String userPassword;
  6. //get、set方法
  7. }

后端数据传送，VO传递

  1. package com.huang.parkinglotserver.vo;
  3. public class UserVo {
  4.     private String userName;
  5.     private String userPassword;
  6.     private String userAuthority;
  7. //get、set方法
  8. }

2.controller层

  1. package com.huang.parkinglotserver.controller;
  3. import com.huang.parkinglotserver.ao.UserAo;
  4. import com.huang.parkinglotserver.service.UserService;
  5. import org.springframework.beans.factory.annotation.Autowired;
  6. import org.springframework.web.bind.annotation.PostMapping;
  7. import org.springframework.web.bind.annotation.RequestBody;
  8. import org.springframework.web.bind.annotation.RequestMapping;
  9. import org.springframework.web.bind.annotation.RestController;
  11. @RestController
  12. @RequestMapping("/user")
  13. public class UserController {
  15.     @Autowired
  16.     private UserService userService;
  18.     @PostMapping("/login")
  19.     public boolean login(@RequestBody UserAo userAo) {
  20.         userService.login(userAo);
  21.         return true;
  22.     }
  24.     @POST
  25.     @Path("/login")
  26.     @Consumes({MediaType.TEXT_PLAIN})
  27.     public Response test(@QueryParam("a") Integer a) {
  28.         return Response.ok(true).build();
  29.     }
  31. }

3.业务逻辑层

service层接口

  1. package com.huang.parkinglotserver.service;
  3. import com.baomidou.mybatisplus.extension.service.IService;
  4. import com.huang.parkinglotserver.ao.UserAo;
  5. import com.huang.parkinglotserver.entity.User;
  7. public interface UserService extends IService<User> {
  9.     /**
  10.      * 登录验证
  11.      *
  12.      * @param userAo 账号、密码
  13.      * @return true成功、false失败
  14.      */
  15.     boolean login(UserAo userAo);
  17. }

service层接口实现类

  1. package com.huang.parkinglotserver.service.impl;
  3. import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
  4. import com.huang.parkinglotserver.ao.UserAo;
  5. import com.huang.parkinglotserver.dao.UserDao;
  6. import com.huang.parkinglotserver.entity.User;
  7. import com.huang.parkinglotserver.service.UserService;
  8. import org.springframework.beans.factory.annotation.Autowired;
  9. import org.springframework.stereotype.Service;
  11. @Service
  12. public class UserServiceImpl extends ServiceImpl<UserDao,User> implements UserService {
  14.     @Autowired
  15.     private UserDao userDao;
  17.     @Override
  18.     public boolean login(UserAo userAo) {
  19.         User user = userDao.login(userAo.getUserName());
  20.         if(user.getUserPassword().equals(userAo.getUserPassword())){
  21.             return true;
  22.         }else{
  23.             return false;
  24.         }
  25.     }
  26. }

4.dao层

  1. package com.huang.parkinglotserver.dao;
  3. import com.baomidou.mybatisplus.core.mapper.BaseMapper;
  4. import com.huang.parkinglotserver.entity.User;
  5. import org.apache.ibatis.annotations.Mapper;
  6. import org.apache.ibatis.annotations.Select;
  8. @Mapper
  9. public interface UserDao extends BaseMapper<User> {
  11.     /**
  12.      * 登录验证
  13.      * @param userName 账号
  14.      * @return user账号密码信息
  15.      */
  16.     @Select("select * from user where user_name = '${value}'")
  17.     User login(String userName);
  19. }

mybatisPlus的映射，一般在resource下的mapper

  1. <?xml version="1.0" encoding="UTF-8" ?> 
  2. <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" > 
  3. <mapper namespace="com.huang.parkinglotserver.dao.UserDao">     
  4.   <select id="login" resultType="com.huang.parkinglotserver.entity.User">        
  5.     select u.id,u.user_name,u.user_password,u.user_authority 
  6.     from user u where user_name = "${value}"     
  7.   </select> 
  8. </mapper>

XML形式实现多表查询

https://blog.csdn.net/weixin_42274148/article/details/121973513?utm_medium=distribute.pc_aggpage_search_result.none-task-blog-2~aggregatepage~first_rank_ecpm_v1~rank_v31_ecpm-8-121973513.pc_agg_new_rank&utm_term=mybatisplus+%E6%9F%A5%E8%AF%A2%E8%A1%A8%E4%B8%AD%E6%89%80%E6%9C%89%E6%95%B0%E6%8D%AE&spm=1000.2123.3001.4430
在PriClassMapper中添加方法

  1. public interface PriClassMapper extends BaseMapper<PriClass> {
  2.     ClassDetail getDetailById(Serializable id);
  3. }

在XML文件中写SQL和映射

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
  3. <mapper namespace="com.example.primarySchool.mapper.PriClassMapper">
  5.   <select id="getDetailById" resultMap="detailedClassResultMap">
  6.     SELECT
  7.     p.class_id AS class_id,
  8.     p.nickname AS cname,
  9.     s.student_id AS student_id,
  10.     s.nickname AS sname
  11.     FROM pri_class p JOIN student s
  12.     ON p.class_id = s.class_id
  13.     WHERE p.class_id = #{id}
  14.   </select>
  16.   <resultMap id="detailedClassResultMap" type="com.example.primarySchool.entity.ClassDetail">
  17.     <result property="classId" column="class_id"/>
  18.     <result property="nickname" column="cname"/>
  19.     <collection property="students" ofType="com.example.primarySchool.entity.Student">
  20.       <id property="studentId" column="student_id"/>
  21.       <result property="nickname" column="sname"/>
  22.       <result property="classId" column="class_id"/>
  23.     </collection>
  24.   </resultMap>
  25. </mapper>

再在service层中调用mapper中自定义的方法，通过getBaseMapper()来获取mapper的实例

  1. public interface IPriClassService extends IService<PriClass> {
  2.     ClassDetail getDetailById(Serializable id);
  3. }
  1. @Service
  2. public class PriClassServiceImpl extends ServiceImpl<PriClassMapper, PriClass> implements IPriClassService {
  3.     @Override
  4.     public ClassDetail getDetailById(Serializable id) {
  5.         return getBaseMapper().getDetailById(id);
  6.     }
  7. }