Spring+MyBatis
1.创建数据库表
用户基本信息表
create table t_user(
user_id int primary key auto_increment,
user_name varchar(20),
user_age int,
user_address varchar(30)
);
2.创建项目完善结构
3. 导入依赖
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- spring-jdbc -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- spring_tx -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- MyBatis依赖 -->
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.6</version>
</dependency>
<!-- mybatis-spring 整合包 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.3.1</version>
</dependency>
<!-- mysql数据库驱动 -->
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<!--druid 阿里的连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.7</version>
</dependency>
4. 根据数据库表创建javabean
package com.wangxing.springmybatis.bean;
public class UserBean {
private Integer userId;
private String userName;
private Integer userAge;
private String userAddress;
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName == null ? null : userName.trim();
}
public Integer getUserAge() {
return userAge;
}
public void setUserAge(Integer userAge) {
this.userAge = userAge;
}
public String getUserAddress() {
return userAddress;
}
public void setUserAddress(String userAddress) {
this.userAddress = userAddress == null ? null : userAddress.trim();
}
}
5.创建数据访问接口
package com.wangxing.springmybatis.mapper;
import com.wangxing.springmybatis.bean.UserBean;
import com.wangxing.springmybatis.bean.UserBeanExample;
import java.util.List;
import org.apache.ibatis.annotations.Param;
public interface UserBeanMapper {
long countByExample(UserBeanExample example);
int deleteByExample(UserBeanExample example);
int deleteByPrimaryKey(Integer userId);
int insert(UserBean record);
int insertSelective(UserBean record);
List<UserBean> selectByExample(UserBeanExample example);
UserBean selectByPrimaryKey(Integer userId);
int updateByExampleSelective(@Param("record") UserBean record, @Param("example") UserBeanExample example);
int updateByExample(@Param("record") UserBean record, @Param("example") UserBeanExample example);
int updateByPrimaryKeySelective(UserBean record);
int updateByPrimaryKey(UserBean record);
}
6.在resources创建mapper文件夹统一保存所有映射文件
7.在src/main/resources创建数据库链接字符串的资源文件【xxxxx.properties】
mydata.properties
mydriver = com.mysql.jdbc.Driver
myurl = jdbc:mysql://127.0.0.1:3306/test
myusername = root
mypassword = 123456
8.在src/main/resources配置MyBatis核心配置文件【mybatis-config.xml】中的内容融入Spring配置文件[applicationContext.xml]中
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
<!-- 配置自动扫描service包 -->
<context:component-scan base-package="com.wangxing.springmybatis.service.impl"></context:component-scan>
<!--配置加载mydata.properties-->
<context:property-placeholder location="classpath:mydata.properties"></context:property-placeholder>
<!--配置数据源-->
<!-- com.alibaba.druid.pool.DruidDataSource-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${mydriver}"></property>
<property name="url" value="${myurl}"></property>
<property name="username" value="${myusername}"></property>
<property name="password" value="${mypassword}"></property>
</bean>
<!-- 配置SqlSessionFactory -->
<!-- org.mybatis.spring.SqlSessionFactoryBean-->
<bean class="org.mybatis.spring.SqlSessionFactoryBean">
<!--注入数据源-->
<property name="dataSource" ref="dataSource"></property>
<!--注入sql映射文件路径-->
<property name="mapperLocations" value="classpath:mapper/UserBeanMapper.xml"></property>
</bean>
<!--配置扫描数据库访问接口包,创建数据库访问接口对象-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.wangxing.springmybatis.mapper"></property>
</bean>
</beans>
9. 创建业务访问接口及其实现类
package com.wangxing.springmybatis.service;
import com.wangxing.springmybatis.bean.UserBean;
import java.util.List;
public interface UserService {
public void insertUser(UserBean userBean);
public void updateUser(UserBean userBean);
public void deleteUser(int userid);
public UserBean selectUserById(int userid);
public List<UserBean> selectUser();
}
package com.wangxing.springmybatis.service.impl;
import com.wangxing.springmybatis.bean.UserBean;
import com.wangxing.springmybatis.mapper.UserBeanMapper;
import com.wangxing.springmybatis.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service("userService")
public class UserServiceImpl implements UserService {
@Autowired
private UserBeanMapper userBeanMapper;
@Override
public void insertUser(UserBean userBean) {
userBeanMapper.insert(userBean);
}
@Override
public void updateUser(UserBean userBean) {
userBeanMapper.updateByPrimaryKey(userBean);
}
@Override
public void deleteUser(int userid) {
userBeanMapper.deleteByPrimaryKey(userid);
}
@Override
public UserBean selectUserById(int userid) {
return userBeanMapper.selectByPrimaryKey(userid);
}
@Override
public List<UserBean> selectUser() {
return userBeanMapper.selectByExample(null);
}
}
10. 测试代码
package com.wangxing.springmybatis.test;
import com.wangxing.springmybatis.bean.UserBean;
import com.wangxing.springmybatis.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.util.List;
public class TsetMain {
public static void main(String[] args) {
ApplicationContext ac=new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = (UserService)ac.getBean("userService");
/*
//测试添加
UserBean userBean=new UserBean();
userBean.setUserName("zhangsan");
userBean.setUserAge(23);
userBean.setUserAddress("西安");
userService.insertUser(userBean);
*/
//测试修改
/*
UserBean userBean=new UserBean();
userBean.setUserId(1);
userBean.setUserName("lisi");
userBean.setUserAge(24);
userBean.setUserAddress("北京");
userService.updateUser(userBean);
*/
//测试根据id查询
//UserBean userBean1=userService.selectUserById(1);
//System.out.println(userBean1.getUserName());
/*
//测试查询所有
List<UserBean> userBeanList=userService.selectUser();
for (UserBean userBean:userBeanList){
System.out.println(userBean.getUserName());
}
*/
userService.deleteUser(1);
}
}
1. 什么事务?
对数据库的一系列操作中,保证同时成功或者同时失败。不能出现成部分成功,失败部分的情况。而这一些列操作称为数据库的事务。
2. 事务的特性
数据库的事务有4大特征:
原子性:指事务是一个不可分割的工作单位,事务的操作要么都发生,要么都不发生.
一致性:事务前后数据的完整性必须保持一致。
隔离性:指多个用户并发访问数据库时,一个用户的事务不能被其他用户的事务干扰,多个并发之间的数据要相互隔离。
持久性:指一个事务一旦被提交,它对数据库中数据的改变就是永久性的,接下来即使数据库发生故障也不应该对其又任何影响。简称ACID。其中隔离性最重要。
3. 事务的隔离级别
如果不考虑隔离性,可能会引发如下问题:
脏读:指一个事务读取到了另一个事务未提交的数据。
不可重复读:在一个事务内读取表中某一行数据,多次读取结果不同(一个事务读取到的另外一个事务提交的数据)
虚读(幻读):时指一个事务内读取到了别的事务插入的数据,导致前后读取不一致。
使用Java操作的时候设置隔离级别由高到低分别为:
Serializable:可避免脏读、不可重复读、虚读情况的发生。
Repeatable read:可避免脏读、不可重复读情况发生。(可重复读)
Read committed:可避免脏读情况的发生。(读已提交)
Read uncommitted:最低级别,以上情况均为无法保证。(读未提交)
值得一提的是:大多数数据库默认的事务隔离级别是Read committed,比如Sql Server , Oracle。Mysql的默认隔离级别是Repeatable read。
Java的JDBC对事务的隔离级别操作
在Java中,可以通过Connection对象来设置数据库的隔离级别,以及控制事务。
Connection中支持的设置隔离级别的常量:
设置数据库的隔离级别:
例如:
Connection conn=DBConnection.getConnection();
设置事物的隔离级别
conn.setTransactionIsolation(Connection.TRANSANCTION_READ_COMMITTED);
获取数据库的隔离级别:
Java的JDBC对事务的操作
1、在操作数据库之前,先取消数据库的自动提交:
2、当数据库出现问题的时候,回滚事务
3、当数据库操作一切都正常,提交事务
4.Spring的事务管理器
Spring提供的事务控制的接口:PlatformTransactionManager其中提供了三个方法:
根据dao层(持久层/数据访问层)使用的不同的框架,PlatformTransactionManager 的主要实现类大致如下:
DataSourceTransactionManager:适用于使用JDBC和MyBatis进行数据持久化操作的情况。
HibernateTransactionManager:适用于使用Hibernate进行数据持久化操作的情况。
5.具体事务管理操作【声明式事务管理】
1. 基于xml方式的事物管理操作
1.数据库中创建t_account账户表,模拟转账,演示spring的事务控制。
create table t_account(
account_id int primary key auto_increment,
user_name varchar(20),
money int
);
insert into t_account values(null,'刘能',10000);
insert into t_account values(null,'赵四',10000);
2. 创建项目完成项目结构,导入依赖
<!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- spring-jdbc -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- spring_tx -->
<!-- https://mvnrepository.com/artifact/org.springframework/spring-tx -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>5.1.5.RELEASE</version>
</dependency>
<!-- MyBatis依赖 -->
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.6</version>
</dependency>
<!-- mybatis-spring 整合包 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.3.1</version>
</dependency>
<!-- mysql数据库驱动 -->
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<!--druid 阿里的连接池-->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.1.7</version>
</dependency>
3. 创建数据访问接口
package com.wangxing.spring.mapper;
import java.util.Map;
//数据访问接口
public interface TransferMapper {
// 加钱
public void addMoney(Map param);
// 减钱
public void lessMoney(Map param);
}
4. 创建数据访问接口对应的SQL映射文件
<?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.wangxing.spring.mapper.TransferMapper">
<update id="addMoney" parameterType="hashMap">
update t_account set money = money + #{number} where user_name = #{username}
</update>
<update id="lessMoney" parameterType="hashMap">
update t_account set money = money - #{number} where user_name = #{username}
</update>
</mapper>
5. 创建业务访问类,并提供具体的业务方法
package com.wangxing.spring.service;
import com.wangxing.spring.mapper.TransferMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.HashMap;
import java.util.Map;
@Service("transferService")
public class TransferService {
@Autowired
private TransferMapper transferMapper;
/**
* 转账方法
* @throws Exception
*/
public void transfer()throws Exception{
Map<String,Object> liuneng=new HashMap<String,Object>();
liuneng.put("username","刘能");
liuneng.put("number",1000);
transferMapper.lessMoney(liuneng);
//int a=10/0;
Map<String,Object> zhaosi=new HashMap<String,Object>();
zhaosi.put("username","赵四");
zhaosi.put("number",1000);
transferMapper.addMoney(zhaosi);
}
}
6. 创建数据库连接文件【mydata.properties】
mydriver = com.mysql.jdbc.Driver
myurl = jdbc:mysql://127.0.0.1:3306/test
myusername = root
mypassword = 123456
7. 创建Spring配置文件
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<!-- 配置自动扫描service包 -->
<context:component-scan base-package="com.wangxing.spring.service"></context:component-scan>
<!--配置加载mydata.properties-->
<context:property-placeholder location="classpath:mydata.properties"></context:property-placeholder>
<!--配置数据源-->
<!-- com.alibaba.druid.pool.DruidDataSource-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${mydriver}"></property>
<property name="url" value="${myurl}"></property>
<property name="username" value="${myusername}"></property>
<property name="password" value="${mypassword}"></property>
</bean>
<!-- 配置SqlSessionFactory -->
<!-- org.mybatis.spring.SqlSessionFactoryBean-->
<bean class="org.mybatis.spring.SqlSessionFactoryBean">
<!--注入数据源-->
<property name="dataSource" ref="dataSource"></property>
<!--注入sql映射文件路径-->
<property name="mapperLocations" value="classpath:mapper/TransferMapper.xml"></property>
</bean>
<!--配置扫描数据库访问接口包,创建数据库访问接口对象-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.wangxing.spring.mapper"></property>
</bean>
<!-- 配置事務管理 -->
<!--1.创建事务管理器对象-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!--2.创建事务-->
<tx:advice id="txAdvice1" transaction-manager="transactionManager">
<tx:attributes>
<tx:method name="transfer"/>
</tx:attributes>
</tx:advice>
<!--3.通过aop将上面创建好的事物,作用到指定的业务方法中 -->
<aop:config>
<aop:pointcut id="point1" expression="execution(* com.wangxing.spring.service.TransferService.transfer())"/>
<aop:advisor advice-ref="txAdvice1" pointcut-ref="point1"></aop:advisor>
</aop:config>
</beans>
2.基于注解方式的事物管理操作
1.在需要使用事务的业务类或者业务处理方法上添加@Transactional
业务类上配置@Transactional表示当前业务类中的所有方法全部存在事务处理
业务处理方法上配置@Transactional表示只有当前业务处理方法上存在事务处理
package com.wangxing.spring.service;
import com.wangxing.spring.mapper.TransferMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import java.util.HashMap;
import java.util.Map;
@Service("transferService")
@Transactional
public class TransferService {
@Autowired
private TransferMapper transferMapper;
/**
* 转账方法
* @throws Exception
*/
public void transfer()throws Exception{
Map<String,Object> liuneng=new HashMap<String,Object>();
liuneng.put("username","刘能");
liuneng.put("number",1000);
transferMapper.lessMoney(liuneng);
int a=10/0;
Map<String,Object> zhaosi=new HashMap<String,Object>();
zhaosi.put("username","赵四");
zhaosi.put("number",1000);
transferMapper.addMoney(zhaosi);
}
}
2. Spring配置文件中开启事务注解
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd">
<!-- 配置自动扫描service包 -->
<context:component-scan base-package="com.wangxing.spring.service"></context:component-scan>
<!--配置加载mydata.properties-->
<context:property-placeholder location="classpath:mydata.properties"></context:property-placeholder>
<!--配置数据源-->
<!-- com.alibaba.druid.pool.DruidDataSource-->
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="driverClassName" value="${mydriver}"></property>
<property name="url" value="${myurl}"></property>
<property name="username" value="${myusername}"></property>
<property name="password" value="${mypassword}"></property>
</bean>
<!-- 配置SqlSessionFactory -->
<!-- org.mybatis.spring.SqlSessionFactoryBean-->
<bean class="org.mybatis.spring.SqlSessionFactoryBean">
<!--注入数据源-->
<property name="dataSource" ref="dataSource"></property>
<!--注入sql映射文件路径-->
<property name="mapperLocations" value="classpath:mapper/TransferMapper.xml"></property>
</bean>
<!--配置扫描数据库访问接口包,创建数据库访问接口对象-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="basePackage" value="com.wangxing.spring.mapper"></property>
</bean>
<!-- 配置事務管理 -->
<!--1.创建事务管理器对象-->
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"></property>
</bean>
<!--开启事务管理注解-->
<!--<tx:annotation-driven transaction-manager="transactionManager"></tx:annotation-driven>-->
<!-- 由于tx:annotation-driven的配置事务管理器的属性transaction-manager的默认值是transactionManager,
我们创建的事务管理器对象的名称也是transactionManager,因此在配置tx:annotation-driven元素时
transaction-manager属性是不用写
-->
<tx:annotation-driven></tx:annotation-driven>
</beans>