SpringBoot implements SSMP integration

1. Integrate JUnit

1. Spring integrates JUnit

There are two core annotations:

1. @RunWith(SpringJUnit4ClassRunner.class) is to set up Spring’s class runner specifically for testing (Spring program executor has its own independent way of running the program, and cannot use the class running method provided by JUnit)
2. @ContextConfiguration(classes = SpringConfig.class) is used to set the Spring core configuration file or configuration class (that is, the specific environment configuration required to load the Spring environment)

//Load the spring-integrated junit-specific class runner
@RunWith(SpringJUnit4ClassRunner.class)
//Specify the corresponding configuration information
@ContextConfiguration(classes = SpringConfig.class)
public class DemoServiceTestCase {<!-- -->
    //Inject the object you want to test
    @Autowired
    private DemoService demoService;
    @Test
    public void testGetById(){<!-- -->
        //Execute the method corresponding to the object to be tested
        System.out.println(accountService.findById(2));
    }
}

2. SpringBoot integrates JUnit

SpringBoot directly simplifies the two almost fixed annotations @RunWith(SpringJUnit4ClassRunner.class) and @ContextConfiguration(classes = SpringConfig.class).

package com.ty;

import com.ty.service.DemoService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class SpringbootDemoApplicationTests {<!-- -->

    @Autowired
    private DemoService demoService;
    
    @Test
    public void getByIdTest(){<!-- -->
        demoService.getById();
    }
}

Note:

Of course, if the package directory where the test class SpringbootDemoApplicationTests is located is different from the SpringBoot startup class SpringbootDemoApplication, JUnit will not be able to find the SpringBoot startup class at startup. Error java.lang.IllegalStateException: Unable to find a @SpringBootConfiguration, you need to use @ContextConfiguration or @SpringBootTest(classes=...) with your test.

Solution: Adjust the package directory where the test class SpringbootDemoApplicationTests is located to be consistent with the SpringBoot startup class SpringbootDemoApplication, or pass @SpringBootTest(classes = SpringbootDemoApplication.class) Specifies the SpringBoot startup class.

2. Integrate MyBatis

1. Spring integration MyBatis

1. The first choice is to introduce a series of Jars to MyBatis

   <dependencies>
       <dependency>
           <groupId>com.alibaba</groupId>
           <artifactId>druid</artifactId>
           <version>1.1.16</version>
       </dependency>
       <dependency>
           <groupId>org.mybatis</groupId>
           <artifactId>mybatis</artifactId>
           <version>3.5.6</version>
       </dependency>
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
           <version>5.1.47</version>
       </dependency>
       <!--1. Import the jar package integrating mybatis and spring-->
       <dependency>
           <groupId>org.mybatis</groupId>
           <artifactId>mybatis-spring</artifactId>
           <version>1.3.0</version>
       </dependency>
       <!--Required package for importing spring operation database-->
       <dependency>
           <groupId>org.springframework</groupId>
           <artifactId>spring-jdbc</artifactId>
           <version>5.2.10.RELEASE</version>
       </dependency>
   </dependencies>
   

2. Database connection information configuration

   jdbc.driver=com.mysql.jdbc.Driver
   jdbc.url=jdbc:mysql://localhost:3306/spring_db?useSSL=false
   jdbc.username=root
   jdbc.password=root
   

3. Define mybatis-specific configuration classes

   //Define mybatis-specific configuration class
   @Configuration
   public class MyBatisConfig {<!-- -->
   //Define and create the bean corresponding to SqlSessionFactory
       @Bean
       public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){<!-- -->
           //SqlSessionFactoryBean is provided by the mybatis-spring package and is an object dedicated to integration.
           SqlSessionFactoryBean sfb = new SqlSessionFactoryBean();
           //Set the data source to replace the environment configuration in the original configuration
           sfb.setDataSource(dataSource);
           //Set type aliases to replace the configuration of typeAliases in the original configuration
           sfb.setTypeAliasesPackage("com.itheima.domain");
           return sfb;
       }
   // Define loading all mapping configurations
       @Bean
       public MapperScannerConfigurer mapperScannerConfigurer(){<!-- -->
           MapperScannerConfigurer msc = new MapperScannerConfigurer();
           msc.setBasePackage("com.itheima.dao");
           return msc;
       }
   
   }
   

4. Spring core configuration

   @Configuration
   @ComponentScan("com.itheima")
   @PropertySource("jdbc.properties")
   public class SpringConfig {<!-- -->
   }
   

5. Configure beans

   @Configuration
   public class JdbcConfig {<!-- -->
       @Value("${jdbc.driver}")
       private String driver;
       @Value("${jdbc.url}")
       private String url;
       @Value("${jdbc.username}")
       private String userName;
       @Value("${jdbc.password}")
       private String password;
   
       @Bean("dataSource")
       public DataSource dataSource(){<!-- -->
           DruidDataSource ds = new DruidDataSource();
           ds.setDriverClassName(driver);
           ds.setUrl(url);
           ds.setUsername(userName);
           ds.setPassword(password);
           return ds;
       }
   }
   

2. SpringBoot integrates MyBatis

Compared with the above, SpringBoot is much simpler.

1. First import the starter mybatis-spring-boot-starter and database driver mysql-connector-java corresponding to MyBatis

    <dependency>
               <groupId>org.mybatis.spring.boot</groupId>
               <artifactId>mybatis-spring-boot-starter</artifactId>
               <version>2.2.0</version>
           </dependency>
   
           <dependency>
               <groupId>mysql</groupId>
               <artifactId>mysql-connector-java</artifactId>
               <version>8.0.27</version>
               <scope>runtime</scope>
           </dependency>
   

2. Configure data source related information

   spring:
     datasource:
       driver-class-name: com.mysql.jdbc.Driver
       url: jdbc:mysql://localhost:3306/ty
       username: root
       password: 123
   

   The driver class is outdated, please replace it with com.mysql.cj.jdbc.Driver

3. Configure Entity and Dao, database SQL mapping needs to add @Mapper to be recognized by the container

   package com.ty.entity;
   
   import lombok.Data;
   
   @Data
   public class TyUser {<!-- -->
   
       private Integer id;
   
       private String name;
   
       private Integer age;
   
   }
   
   

    package com.ty.dao;
   \t
   import com.ty.entity.TyUser;
   import org.apache.ibatis.annotations.Mapper;
   import org.apache.ibatis.annotations.Select;
   \t
   @Mapper
   public interface DemoDao {<!-- -->
   \t
   @Select("select * from ty_user where id = #{id}")
   public TyUser getById(Integer id);
   \t
   }
   

4. Through the test class, it can be called by injecting DemoService.

   package com.ty;
   
   import com.ty.dao.DemoDao;
   import com.ty.entity.TyUser;
   import org.junit.jupiter.api.Test;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.boot.test.context.SpringBootTest;
   
   @SpringBootTest
   class SpringbootDemoApplicationTests {<!-- -->
       @Autowired
       private DemoDao demoDao;
   
       @Test
       public void getByIdTestDao(){<!-- -->
           TyUser byId = demoDao.getById(1);
           System.out.println(byId);
       }
   
   }
   

3. Integrate MyBatis-Plus

MyBaitsPlus (MP for short), a technology developed by Chinese people, is in line with Chinese development habits

1. Import mybatis_plus starter mybatis-plus-boot-starter

   <dependency>
       <groupId>com.baomidou</groupId>
       <artifactId>mybatis-plus-boot-starter</artifactId>
       <version>3.4.3</version>
   </dependency>
   

2. Configure data source related information

    spring:
   datasource:
   driver-class-name: com.mysql.jdbc.Driver
   url: jdbc:mysql://localhost:3306/ty
   username: root
   password: 123
   

3. Dao mapping interface and entity class

   package com.example.springboot_mybatisplus_demo.dao;
   
   import com.baomidou.mybatisplus.core.mapper.BaseMapper;
   import com.example.springboot_mybatisplus_demo.entity.User;
   import org.apache.ibatis.annotations.Mapper;
   
   @Mapper
   public interface DemoDao extends BaseMapper<User> {<!-- -->
   }
   
   

   The entity class name is consistent with the table name and can be automatically mapped. When the table name has a prefix, the common prefix of the table can be configured in application.yml.

   package com.example.springboot_mybatisplus_demo.entity;
   
   import lombok.Data;
   
   @Data
   public class User {<!-- -->
   
       private Integer id;
   
       private String name;
   
       private Integer age;
   }
   
   

   mybatis-plus:
     global-config:
       db-config:
         table-prefix: ty_ #Set the common prefix name of all tables to tbl_
   

4. Write a test class and inject DemoDao to call a series of methods provided by mybatis_plus. The inherited BaseMapper interface helps developers reserve several commonly used API interfaces, simplifying the development of common API interfaces.

   package com.example.springboot_mybatisplus_demo;
   
   import com.example.springboot_mybatisplus_demo.dao.DemoDao;
   import com.example.springboot_mybatisplus_demo.entity.User;
   import org.junit.jupiter.api.Test;
   import org.springframework.beans.factory.annotation.Autowired;
   import org.springframework.boot.test.context.SpringBootTest;
   
   @SpringBootTest
   class SpringbootMybatisplusDemoApplicationTests {<!-- -->
   
       @Autowired
       private DemoDao demoDao;
   
       @Test
       public void getByIdTestDao(){<!-- -->
           User byId = demoDao.selectById(1);
           System.out.println(byId);
       }
   
   }