整合Mybatis
整合Mybatis
一、回忆mybatis
建立数据库
CREATE DATABASE `mybatis`
USE `mybatis`
CREATE TABLE `user`(
`id` INT(20) NOT NULL,
`name` VARCHAR(30) DEFAULT NULL,
`password` VARCHAR(30) DEFAULT NULL,
PRIMARY KEY(`id`)
)ENGINE=INNODB DEFAULT CHARSET=utf8;
INSERT INTO `user`(`id`,`name`,`password`)
VALUES (1,'周周','123456'),(2,'莹莹','zxcvbn'),(3,'酱酱','123456');
SELECT * FROM `user`
User实体类
//使用注解需要导入lombok仓库
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private int id;
private String name;
private String password;
}
接口
import java.util.List;
public interface UserMapper {
List<User> getUser();
}
mybatis-config.xml
<configuration>
<typeAliases>
<package name="com.cm.pojo"/>
typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
dataSource>
environment>
environments>
<mappers>
<mapper resource="com/cm/mapper/xml/usermapper.xml"/>
mappers>
configuration>
usermapper.xml
<mapper namespace="com.cm.mapper.UserMapper">
<select id="getUser" resultType="User">
select * from user;
select>
mapper>
测试
public class MyTest {
@Test
public void test1() throws IOException {
SqlSessionFactory sqlSession = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
SqlSession session = sqlSession.openSession();
UserMapper mapper = session.getMapper(UserMapper.class);
List<User> user = mapper.getUser();
for (User user1 : user) {
System.out.println(user1);
}
}
}
运行结果
二、Mybatis-spring
1.导入相关jar包
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<groupId>com.cmgroupId>
<artifactId>mybatis-springartifactId>
<version>1.0-SNAPSHOTversion>
<dependencies>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.8version>
dependency>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>4.12version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatisartifactId>
<version>3.5.2version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>5.1.47version>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webmvcartifactId>
<version>5.1.10.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-jdbcartifactId>
<version>5.1.10.RELEASEversion>
dependency>
<dependency>
<groupId>org.aspectjgroupId>
<artifactId>aspectjweaverartifactId>
<version>1.9.4version>
dependency>
<dependency>
<groupId>org.mybatisgroupId>
<artifactId>mybatis-springartifactId>
<version>2.0.2version>
dependency>
dependencies>
<build>
<resources>
<resource>
<directory>src/main/javadirectory>
<includes>
<include>**/*.propertiesinclude>
<include>**/*.xmlinclude>
includes>
<filtering>truefiltering>
resource>
resources>
build>
project>
User实体类不变
接口
public interface UserMapper {
List<User> getUser();
}
编写applicationContext.xml
查看官网http://mybatis.org/spring/zh/index.html
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<aop:config>
<aop:pointcut id="txPointCut" expression="execution(* com.cm.mapper.*.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
aop:config>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
bean>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="typeAliasesPackage" value="com.cm.pojo"/>
<property name="mapperLocations" value="classpath:com/cm/mapper/xml/usermapper.xml"/>
bean>
<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
<constructor-arg index="0" ref="sqlSessionFactory" />
bean>
<bean id="userMapperImpl" class="com.cm.mapper.impl.UserMapperImpl">
<property name="sqlSession" ref="sqlSession"/>
bean>
beans>
mybatis-config.xml
<configuration>
configuration>
usermapper.xml
<mapper namespace="com.cm.mapper.UserMapper">
<select id="getUser" resultType="User">
select * from user;
select>
mapper>
UserMapperImpl实现类
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;
public class UserMapperImpl implements UserMapper {
private SqlSessionTemplate sqlSession;
public void setSqlSession(SqlSessionTemplate sqlSession) {
this.sqlSession = sqlSession;
}
public List<User> getUser() {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
return mapper.getUser();
}
}
测试
@Test
public void test2() {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserMapper userMapperImpl = (UserMapper) context.getBean("userMapperImpl");
List<User> user = userMapperImpl.getUser();
for (User user1 : user) {
System.out.println(user1);
}
}
运行结果
三、实现Mybatis-spring事务
1.事务ACID原则
-
原子性
-
一致性
-
隔离性
- 多个业务可能操作同一个资源，防止数据损坏
-
持久性
- 事务一旦提交，无论系统发生什么问题，结果都不会再被影响，被持久化的写到存储器中！
事务注意点：
- 把一组业务当成一个业务来做；要么都成功，要么都失败！
- 事务在项目开发中，十分的重要，涉及到数据的一致性问题，不能马虎！
- 确保完整性和一致性！
2、spring中的事务管理
方式一：不采用声明式事务
User实体类不变
接口
import java.util.List;
public interface UserMapper {
List<User> getUser();
int addUser(User user);
int deleteUser(int id);
}
实现类
（注意，这里的添加和删除的操作是在getUser方法中实现的）
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;
public class UserMapperImpl implements UserMapper {
private SqlSessionTemplate sqlSession;
public void setSqlSession(SqlSessionTemplate sqlSession) {
this.sqlSession = sqlSession;
}
public List<User> getUser() {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User user = new User(4, "cm", "333333");
mapper.addUser(user);
mapper.deleteUser(3);
return mapper.getUser();
}
public int addUser(User user) {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
return mapper.addUser(user);
}
public int deleteUser(int id) {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
return mapper.deleteUser(id);
}
}
usermappper.xml
(这里会故意将删除的sql语句写错)
<mapper namespace="com.cm.mapper.UserMapper">
<select id="getUser" resultType="User">
select * from user;
select>
<insert id="addUser" parameterType="User">
insert into user(id, name, password) value (#{id}, #{name}, #{password});
insert>
<delete id="deleteUser" parameterType="int">
deletes from user where id = #{id};
delete>
mapper>
applicationContext.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<aop:config>
<aop:pointcut id="txPointCut" expression="execution(* com.cm.mapper.*.*(..))"/>
aop:config>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
bean>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="typeAliasesPackage" value="com.cm.pojo"/>
<property name="mapperLocations" value="classpath:com/cm/mapper/xml/usermapper.xml"/>
bean>
<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
<constructor-arg index="0" ref="sqlSessionFactory" />
bean>
<bean id="userMapperImpl" class="com.cm.mapper.impl.UserMapperImpl">
<property name="sqlSession" ref="sqlSession"/>
bean>
beans>
测试
@Test
public void test2() {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserMapper userMapperImpl = (UserMapper) context.getBean("userMapperImpl");
List<User> user = userMapperImpl.getUser();
for (User user1 : user) {
System.out.println(user1);
}
}
运行结果
虽然报错了，但是添加的操作确实实现了。
我们应该避免这种情况，满足事务的ACID性，就需要使用声明式事务了。
方式二：使用声明式事务
这里只需要改变applicationContext.xml和实现类即可
applicationContext.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
https://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/tx
https://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
https://www.springframework.org/schema/aop/spring-aop.xsd">
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<constructor-arg ref="dataSource" />
bean>
<tx:advice id="txAdvice" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="*" propagation="REQUIRED"/>
tx:attributes>
tx:advice>
<aop:config>
<aop:pointcut id="txPointCut" expression="execution(* com.cm.mapper.*.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="txPointCut"/>
aop:config>
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
bean>
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="typeAliasesPackage" value="com.cm.pojo"/>
<property name="mapperLocations" value="classpath:com/cm/mapper/xml/usermapper.xml"/>
bean>
<bean id="sqlSession" class="org.mybatis.spring.SqlSessionTemplate">
<constructor-arg index="0" ref="sqlSessionFactory" />
bean>
<bean id="userMapperImpl" class="com.cm.mapper.impl.UserMapperImpl">
<property name="sqlSession" ref="sqlSession"/>
bean>
beans>
实现类（就是换了一下参数数值）
import org.mybatis.spring.SqlSessionTemplate;
import java.util.List;
public class UserMapperImpl implements UserMapper {
private SqlSessionTemplate sqlSession;
public void setSqlSession(SqlSessionTemplate sqlSession) {
this.sqlSession = sqlSession;
}
public List<User> getUser() {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User user = new User(5, "cm", "333333");
mapper.addUser(user);
mapper.deleteUser(4);
return mapper.getUser();
}
public int addUser(User user) {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
return mapper.addUser(user);
}
public int deleteUser(int id) {
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
return mapper.deleteUser(id);
}
}
运行后会报相同的错误，但是添加数据并没有成功。
这就非常符合事务的ACID要求。
只有当我们把usermapper.xml文件中的sql语句修改正确了，事务才会提交成功，我们对数据库的操作才会成功！
以上就是Mybatis-spring的核心内容。