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This article mainly introduces the SpringBoot to achieve ORM operation MySQL method of what related knowledge, the content is detailed and easy to understand, the operation is simple and fast, has a certain reference value, I believe you will have something to gain after reading this SpringBoot ORM operation MySQL method, let's take a look at it.

Use mybatis framework to manipulate data and integrate mybatis in springboot framework

Steps to use:

The mybatis startup depends on completing the automatic configuration of mybatis objects, which are placed in containers.

Org.springframework.boot spring-boot-starter-web org.mybatis.spring.boot mybatis-spring-boot-starter 2.2.2 mysql mysql-connector-java runtime org.springframework.boot spring-boot-starter-test test

Pom.xml specifies that the xml file in the src/main/java directory is included in the classpath.

Src/main/java * * / .xml org.springframework.boot spring-boot-maven-plugin

Create the entity class Studnet

Create the Dao interface StudentDao and create a method to query the students.

/ * * @ Mapper: tell MyBatis that this is the dao interface, and create a proxy object for this interface, * location: above the class. * * / @ Mapperpublic interface StudentDao {Student selectById (@ Param ("stuId") Integer id);}

Create the Mapper file and xml file corresponding to the Dao interface, and write sql statements.

/ * * @ Mapper: tell MyBatis that this is the dao interface, and create a proxy object for this interface, * location: above the class. * * / @ Mapperpublic interface StudentDao {Student selectById (@ Param ("stuId") Integer id);} select id,name,age from student where id=# {stuId}

Create the servlet layer object, create the StudentService interface and its implementation class. To call the method of the dao object to complete the operation of the database.

Package com.firewolf.service;public interface StudentService {Student queryStudent (Integer id);} package com.firewolf.service.impl;@Servicepublic class StudentServiceImpl implements StudentService {@ Resource private StudentDao studentDao; @ Override public Student queryStudent (Integer id) {Student student=studentDao.selectById (id); return student;}}

Create a Controller object and access Service.

Controllerpublic class StudentController {@ Resource private StudentService studentService; @ RequestMapping ("/ student/query") @ ResponseBody public String queryStudent (Integer id) {Student student = studentService.queryStudent (id); return student.toString ();}}

Write the application.properties file.

Configure connection information for the database

Server.port=9001server.servlet.context-path=/orm# connects to the database spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driverspring.datasource.url=jdbc:mysql://localhost:3306/springdb?useUnicode=true&characterEncoding=UTF-8&serverTimezone=GMT%2B8spring.datasource.username=rootspring.datasource.password=991231gao1. The first way: @ Mapper

Mapper: put it on top of the dao interface, which is required for each interface.

/ * * @ Mapper: tell MyBatis that this is the dao interface, and create a proxy object for this interface, * location: above the class. * * / @ Mapperpublic interface StudentDao {Student selectById (@ Param ("stuId") Integer id);} 2 The second way @ MapperScan/** * @ MapperScan: find the Dao interface and the Mapper file. * the package name of the basePackages:dao API * * / @ SpringBootApplication@MapperScan (basePackages = {"com.firewolf.dao", "com.firewolf.mapper"}) public class Application {public static void main (String [] args) {SpringApplication.run (Application.class, args);}} 3. The third way: Mapper files and Dao interfaces are managed separately.

Now put the Mapper file in resources

Create a subdirectory in the resources directory, such as mapper

Put the mapper file in the mapper directory.

In the application.properties file, specify the directory of the mapper file.

# specify the location of the mapper file, the log mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl of mybatis.mapper-locations=classpath:mapper/*.xml# mybaitis

Specify the directory in pom.xml and compile the files in the resources directory into the target directory.

Src/main/resources * / *. * 4. Business

Transactions in the spring framework

Objects that manage transactions: transaction managers (interfaces, interfaces have many implementation classes).

For example: access the database using jdbc or mybatis, and use the transaction manager: DataSourceTransactionManager

Declarative transactions: specify the content of transaction control in the xml configuration file or using annotations.

Control transactions: isolation level, propagation behavior, timeout.

Transaction processing mode

@ Transactional in the spring framework

The aspectj framework can declare the contents of transaction control in the xml configuration file.

Using transactions in springboot: both of the above are fine.

Add @ Transactional to the top of the business method, and after adding annotations, the method has transactional functionality.

Explicitly on top of the main startup class, add @ EnableTransactionManager.

SpringBootApplication@EnableTransactionManagement@MapperScan (value= "com.firewolf.dao") public class Application {public static void main (String [] args) {SpringApplication.run (Application.class, args);}}

Example:

/ * * @ Transactional: indicates that the method has transaction support * default: use the isolation level of the library, REQUIRED propagation behavior Timeout-1 * throws a runtime exception and rolls back the transaction * / @ Transactional@Overridepublic int addStudent (Student student) {System.out.println ("business method addStudent"); int rows = studentDao.insert (student); System.out.println ("execute sql statement"); / / throws a runtime exception to roll back the transaction / / int m = 10 / 0; return rows } this is the end of the article on "what are the ways for SpringBoot to implement ORM and operate MySQL?" Thank you for reading! I believe that everyone has a certain understanding of the knowledge of "what are the methods of SpringBoot to achieve ORM and operate MySQL". If you want to learn more knowledge, you are welcome to follow the industry information channel.

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