ch05-SpringBoot 集成 MyBatis
- 1.1 SpringBoot 集成 MyBatis 例子
- 1.1.1 创建数据库表
- 1.1.2 加入 Maven依赖
- 1.1.3 加入 resources 插件
- 1.1.4 配置数据源
- 1.1.5 创建 Student 实体类
- 1.1.6 创建 StudentDao 接口
- 1.1.7 创建 StudentDao.xml
- 1.1.8 创建StudentService 接口
- 1.1.9 创建StudentServiceImpl 实现类
- 1.1.10 创建 StudentController 类
- 1.2 使用@MapperScan
- 1.3 Mapper文件和Dao接口分开管理
- 1.4 事务
- 1.4.1 SpringBoot 实现事务
- 1)pom.xml
- 2)配置 application.properties
- 3)创建 Student 实体类
- 4)创建 StudentDao 接口与 mapper 文件
- 5)创建 service 接口及实现类
- 6)创建 Controller
- 7)修改主启动类
使用MyBatis框架操作数据, 在SpringBoot框架集成MyBatis
使用步骤:
1.mybatis起步依赖 : 完成mybatis对象自动配置, 对象放在容器中
2.pom.xml 指定把 src/main/java 目录中的 xml 文件包含到 classpath 中
3.创建实体类 Student
4.创建 Dao 接口 StudentDao , 创建一个查询学生的方法
5.创建 Dao 接口对应的 Mapper 文件, xml 文件, 写sql语句
6.创建Service层对象,创建StudentService接口和他的实现类。 去dao对象的方法。完成数据库的操作
7.创建Controller对象,访问Service。
8.写application.properties文件,配置数据库的连接信息。
1.1 SpringBoot 集成 MyBatis 例子
1.1.1 创建数据库表
1.1.2 加入 Maven依赖
<dependencies>
<!--web的起步依赖-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--mybatis的起步依赖-->
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.1</version>
</dependency>
<!--mysql驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<!--测试-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
1.1.3 加入 resources 插件
<build>
<!--加入 resource 插件-->
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>
</build>
1.1.4 配置数据源
server.port=9001
server.servlet.context-path=/orm
#连接数据库
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=123456
1.1.5 创建 Student 实体类
package com.suyv.model;
public class Student {
private Integer id;
private String name;
private Integer age;
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
'}';
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
1.1.6 创建 StudentDao 接口
package com.suyv.dao;
import com.suyv.model.Student;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
/**
* @mapper 告诉mybatis这是dao接口,创建此接口的代理对象
*/
@Mapper
public interface StudentDao {
Student selectById(@Param("stuId") Integer id);
}
1.1.7 创建 StudentDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.suyv.dao.StudentDao">
<select id="selectById" resultType="com.suyv.model.Student">
select * from student where id=#{stuId}
</select>
</mapper>
1.1.8 创建StudentService 接口
package com.suyv.service;
import com.suyv.model.Student;
public interface StudentService {
Student queryStudent(Integer id);
}
1.1.9 创建StudentServiceImpl 实现类
package com.suyv.service.impl;
import com.suyv.dao.StudentDao;
import com.suyv.model.Student;
import com.suyv.service.StudentService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class StudentServiceImpl implements StudentService {
@Resource
private StudentDao studentDao;
@Override
public Student queryStudent(Integer id) {
Student student = studentDao.selectById(id);
return student;
}
}
1.1.10 创建 StudentController 类
package com.suyv.controller;
import com.suyv.model.Student;
import com.suyv.service.StudentService;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.annotation.Resource;
@Controller
public class StudentController {
@Resource
private StudentService studentService;
@RequestMapping("/student/query")
@ResponseBody
public String queryStudent(Integer id){
Student student = studentService.queryStudent(id);
return student.toString();
}
}
1.2 使用@MapperScan
在 Dao 接口上面加入@Mapper,需要在每个接口都加入注解。 当 Dao 接口多的时候不方便。可以使用如下的方式解决。
主类上添加注解包扫描:@MapperScan(“com.suyv.dao”)
package com.suyv;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
/**
* @MapperScan : 扫描所有的 mybatis 的 dao 接口
* 位置:在主类的上面
* 属性:basePackages:指定 dao 接口的所在的包名。
* dao 接口和 mapper 文件依然在同一目录
*/
@SpringBootApplication
@MapperScan(basePackages = "com.suyv.dao")
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
1.3 Mapper文件和Dao接口分开管理
现在把Mapper文件放在resources目录下
1)在resources目录中创建子目录(自定义的), 例如mapper
2)把mapper文件放到 mapper目录中
3)在application.properties文件中,指定mapper文件的目录
#指定mapper文件位置
mybatis.mapper-locations=classpath:mapper/*.xml
#mybatis日志
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
4)在pom.xml中指定 把resources目录中的文件 , 编译到目标目录中
<!--resources插件-->
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>
1.4 事务
Spring框架中的事务:
1)管理事务的对象: 事务管理器(接口, 接口有很多的实现类)
例如:使用Jdbc或mybatis访问数据库,使用的事务管理器:DataSourceTransactionManager
2)声明式事务: 在xml配置文件或者使用注解说明事务控制的内容
控制事务: 隔离级别,传播行为, 超时时间
3)事务处理方式:
1.Spring框架中的@Transactional
2.aspectj框架可以在xml配置文件中,声明事务控制的内容
SpringBoot中使用事务: 上面的两种方式都可以,底层依然采用的是 Spring 本身提供的事务管理。
➢ 在入口类中使用注解 @EnableTransactionManagement 开启事务支持
➢ 在访问数据库的 Service 方法上添加注解 @Transactional 即可
1.4.1 SpringBoot 实现事务
1)pom.xml
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
<!--加入 resource 插件-->
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.*</include>
</includes>
</resource>
</resources>
</build>
2)配置 application.properties
server.port=9001
server.servlet.context-path=/orm
#连接数据库
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=123456
#指定mapper文件位置
mybatis.mapper-locations=classpath:mapper/*.xml
#mybatis日志
mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
3)创建 Student 实体类
package com.suyv.model;
public class Student {
private Integer id;
private String name;
private Integer age;
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", age=" + age +
'}';
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
4)创建 StudentDao 接口与 mapper 文件
StudentDao.java
package com.suyv.dao;
import com.suyv.model.Student;
public interface StudentDao {
int addStudent(Student student);
}
StudentDao.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.suyv.dao/StudentDao">
<insert id="addStudent">
insert into student(name,age) value (#{name},#{age})
</insert>
</mapper>
5)创建 service 接口及实现类
StudentService.java
package com.suyv.service;
import com.suyv.model.Student;
public interface StudentService {
int addStudent(Student student);
}
StudentServiceImpl.java
package com.suyv.service.impl;
import com.suyv.dao.StudentDao;
import com.suyv.model.Student;
import com.suyv.service.StudentService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import javax.annotation.Resource;
@Service
public class StudentServiceImpl implements StudentService {
@Resource
private StudentDao studentDao;
@Transactional
@Override
public int addStudent(Student student) {
System.out.println("业务方法addStudent");
int rows = studentDao.addStudent(student);
// 抛出运行时异常
int m = 10/0;
System.out.println("执行sql语句");
return rows;
}
}
6)创建 Controller
package com.suyv.controller;
import com.suyv.model.Student;
import com.suyv.service.StudentService;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.annotation.Resource;
@Controller
public class StudentController {
@Resource
private StudentService studentService;
@RequestMapping("/addStudent")
@ResponseBody
public String addStudent(String name,Integer age){
Student student = new Student();
student.setName(name);
student.setAge(age);
int rows = studentService.addStudent(student);
return "添加学生:" + rows;
}
}
7)修改主启动类
package com.suyv;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.transaction.annotation.EnableTransactionManagement;
@EnableTransactionManagement
@SpringBootApplication
@MapperScan(basePackages = "com.suyv.dao")
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}