spring基础之五->Spring AOP事务的应用配置

头像
萌妹子_liu
    阅读 35 分钟

    1、Spring JdbcTemplate

    ​ 在spring中为了更加方便的操作JDBC，在JDBC的基础之上定义了一个抽象层，此设计的目的是为不同类型的JDBC操作提供模板方法，每个模板方法都能控制整个过程，并允许覆盖过程中的特定任务，通过这种方式，可以尽可能保留灵活性，将数据库存取的工作量讲到最低。

    1、配置并测试数据源

    pom.xml

    <?xml version="1.0" encoding="UTF-8"?>
<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>4.0.0</modelVersion>

    <groupId>com.mashibing</groupId>
    <artifactId>spring_demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.21</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/cglib/cglib -->
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.3.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.aspectj/aspectjweaver -->
        <dependency>
            <groupId>org.aspectj</groupId>
            <artifactId>aspectjweaver</artifactId>
            <version>1.9.5</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/aopalliance/aopalliance -->
        <dependency>
            <groupId>aopalliance</groupId>
            <artifactId>aopalliance</artifactId>
            <version>1.0</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework/spring-aspects -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>
    </dependencies>

</project>

    dbconfig.properties

    jdbc.username=root123
password=123456
url=jdbc:mysql://localhost:3306/demo
driverClassName=com.mysql.jdbc.Driver

    applicationContext.xml

    <?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: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/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd
">
    <context:property-placeholder location="classpath:dbconfig.properties"></context:property-placeholder>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="driverClassName" value="${jdbc.driverClassName}"></property>
    </bean>
</beans>

    MyTest.java

    import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.sql.SQLException;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        DruidDataSource dataSource = context.getBean("dataSource", DruidDataSource.class);
        System.out.println(dataSource);
        System.out.println(dataSource.getConnection());
    }
}
    2、给spring容器添加JdbcTemplate

    ​ spring容器提供了一个JdbcTemplate类，用来方便操作数据库。

    1、添加pom依赖

    pom.xml

            <!-- https://mvnrepository.com/artifact/org.springframework/spring-orm -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-orm</artifactId>
            <version>5.2.3.RELEASE</version>
        </dependency>

    jdbcTemplate.xml

    <?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: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/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd
">
    <context:property-placeholder location="classpath:dbconfig.properties"></context:property-placeholder>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="driverClassName" value="${jdbc.driverClassName}"></property>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource"></constructor-arg>
    </bean>
</beans>

    MyTest.java

    import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;

import java.sql.SQLException;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        System.out.println(jdbcTemplate);
    }
}
    3、插入数据

    MyTest.java

    import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;

import java.sql.SQLException;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        String sql = "insert into emp(empno,ename) values(?,?)";
        int result = jdbcTemplate.update(sql, 1111, "zhangsan");
        System.out.println(result);
    }
}
    4、批量插入数据

    MyTest.java

    import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        String sql = "insert into emp(empno,ename) values(?,?)";
        List<Object[]> list = new ArrayList<Object[]>();
        list.add(new Object[]{1,"zhangsan1"});
        list.add(new Object[]{2,"zhangsan2"});
        list.add(new Object[]{3,"zhangsan3"});
        int[] result = jdbcTemplate.batchUpdate(sql, list);
        for (int i : result) {
            System.out.println(i);
        }
    }
}
    5、查询某个值，并以对象的方式返回

    MyTest.java

    import com.mashibing.bean.Emp;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.sql.SQLException;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        String sql = "select * from emp where empno = ?";
        Emp emp = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<>(Emp.class), 7369);
        System.out.println(emp);
    }
}
    6、查询返回集合对象

    MyTest.java

    import com.mashibing.bean.Emp;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.sql.SQLException;
import java.util.List;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        String sql = "select * from emp where sal > ?";
        List<Emp> query = jdbcTemplate.query(sql, new BeanPropertyRowMapper<>(Emp.class), 1500);
        for (Emp emp : query) {
            System.out.println(emp);
        }
    }
}
    7、返回组合函数的值

    MyTest.java

    import com.mashibing.bean.Emp;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import java.sql.SQLException;
import java.util.List;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        JdbcTemplate jdbcTemplate = context.getBean("jdbcTemplate", JdbcTemplate.class);
        String sql = "select max(sal) from emp";
        Double aDouble = jdbcTemplate.queryForObject(sql, Double.class);
        System.out.println(aDouble);
    }
}
    8、使用具备具名函数的JdbcTemplate

    jdbcTemplate.xml

    <?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: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/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd
">
    <context:property-placeholder location="classpath:dbconfig.properties"></context:property-placeholder>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="driverClassName" value="${jdbc.driverClassName}"></property>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource"></constructor-arg>
    </bean>
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource"></constructor-arg>
    </bean>
</beans>

    MyTest.java

    import com.mashibing.bean.Emp;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        NamedParameterJdbcTemplate jdbcTemplate = context.getBean("namedParameterJdbcTemplate", NamedParameterJdbcTemplate.class);
        String sql = "insert into emp(empno,ename) values(:empno,:ename)";
        Map<String,Object> map = new HashMap<>();
        map.put("empno",2222);
        map.put("ename","sili");
        int update = jdbcTemplate.update(sql, map);
        System.out.println(update);
    }
}
    9、整合EmpDao

    jdbcTemplate.xml

     <context:component-scan base-package="com.mashibing"></context:component-scan>

    EmpDao.java

    package com.mashibing.dao;

import com.mashibing.bean.Emp;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;

public class EmpDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    public void save(Emp emp){
        String sql = "insert into emp(empno,ename) values(?,?)";
        int update = jdbcTemplate.update(sql, emp.getEmpno(), emp.getEname());
        System.out.println(update);
    }
}

    MyTest.java

    import com.mashibing.bean.Emp;
import com.mashibing.dao.EmpDao;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;

import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        EmpDao empDao = context.getBean("empDao", EmpDao.class);
        empDao.save(new Emp(3333,"wangwu"));
    }
}

    2、声明式事务

    1、环境准备

    tx.sql

    /*
Navicat MySQL Data Transfer

Source Server         : localhost
Source Server Version : 50528
Source Host           : localhost:3306
Source Database       : tx

Target Server Type    : MYSQL
Target Server Version : 50528
File Encoding         : 65001

Date: 2020-02-13 19:19:32
*/

SET FOREIGN_KEY_CHECKS=0;
-- ----------------------------
-- Table structure for `account`
-- ----------------------------
DROP TABLE IF EXISTS `account`;
CREATE TABLE `account` (
  `username` varchar(10) NOT NULL DEFAULT '',
  `balance` double DEFAULT NULL,
  PRIMARY KEY (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of account
-- ----------------------------
INSERT INTO account VALUES ('lisi', '1000');
INSERT INTO account VALUES ('zhangsan', '1000');

-- ----------------------------
-- Table structure for `book`
-- ----------------------------
DROP TABLE IF EXISTS `book`;
CREATE TABLE `book` (
  `id` int(10) NOT NULL,
  `book_name` varchar(10) DEFAULT NULL,
  `price` double DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of book
-- ----------------------------
INSERT INTO book VALUES ('1', '西游记', '100');
INSERT INTO book VALUES ('2', '水浒传', '100');
INSERT INTO book VALUES ('3', '三国演义', '100');
INSERT INTO book VALUES ('4', '红楼梦', '100');

-- ----------------------------
-- Table structure for `book_stock`
-- ----------------------------
DROP TABLE IF EXISTS `book_stock`;
CREATE TABLE `book_stock` (
  `id` int(255) NOT NULL DEFAULT '0',
  `stock` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

-- ----------------------------
-- Records of book_stock
-- ----------------------------
INSERT INTO book_stock VALUES ('1', '1000');
INSERT INTO book_stock VALUES ('2', '1000');
INSERT INTO book_stock VALUES ('3', '1000');
INSERT INTO book_stock VALUES ('4', '1000');

    BookDao.java

    package com.mashibing.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository
public class BookDao {

    @Autowired
    JdbcTemplate jdbcTemplate;

    /**
     * 减去某个用户的余额
     * @param userName
     * @param price
     */
    public void updateBalance(String userName,int price){
        String sql = "update account set balance=balance-? where username=?";
        jdbcTemplate.update(sql,price,userName);
    }

    /**
     * 按照图书的id来获取图书的价格
     * @param id
     * @return
     */
    public int getPrice(int id){
        String sql = "select price from book where id=?";
        return jdbcTemplate.queryForObject(sql,Integer.class,id);
    }

    /**
     * 减库存，减去某本书的库存
     * @param id
     */
    public void updateStock(int id){
        String sql = "update book_stock set stock=stock-1 where id=?";
        jdbcTemplate.update(sql,id);
    }
}

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    public void checkout(String username,int id){

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }
}

    MyTest.java

    import com.mashibing.service.BookService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import java.sql.SQLException;

public class MyTest {
    public static void main(String[] args) throws SQLException {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        BookService bookService = context.getBean("bookService", BookService.class);
        bookService.checkout("zhangsan","1");
    }
}

    总结：在事务控制方面，主要有两个分类：

    编程式事务：在代码中直接加入处理事务的逻辑，可能需要在代码中显式调用beginTransaction()、commit()、rollback()等事务管理相关的方法

    声明式事务：在方法的外部添加注解或者直接在配置文件中定义，将事务管理代码从业务方法中分离出来，以声明的方式来实现事务管理。spring的AOP恰好可以完成此功能：事务管理代码的固定模式作为一种横切关注点，通过AOP方法模块化，进而实现声明式事务。

    2、声明式事务的简单配置

    ​ Spring从不同的事务管理API中抽象出了一整套事务管理机制，让事务管理代码从特定的事务技术中独立出来。开发人员通过配置的方式进行事务管理，而不必了解其底层是如何实现的。

    ​ Spring的核心事务管理抽象是PlatformTransactionManager。它为事务管理封装了一组独立于技术的方法。无论使用Spring的哪种事务管理策略(编程式或声明式)，事务管理器都是必须的。

    ​ 事务管理器可以以普通的bean的形式声明在Spring IOC容器中。下图是spring提供的事务管理器
    image.png

    1、在配置文件中添加事务管理器

    jdbcTemplate.xml

    <?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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       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/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/tx
       https://www.springframework.org/schema/tx/spring-tx.xsd
">
    <context:component-scan base-package="com.mashibing"></context:component-scan>
    <context:property-placeholder location="classpath:dbconfig.properties"></context:property-placeholder>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="driverClassName" value="${jdbc.driverClassName}"></property>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource"></constructor-arg>
    </bean>
    <!--事务控制-->
    <!--配置事务管理器的bean-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!--开启基于注解的事务控制模式，依赖tx名称空间-->
    <tx:annotation-driven transaction-manager="transactionManager"></tx:annotation-driven>
</beans>

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional
    public void checkout(String username,int id){

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }
}
    3、事务配置的属性

    ​ isolation：设置事务的隔离级别

    ​ propagation：事务的传播行为

    ​ noRollbackFor：那些异常事务可以不回滚

    ​ noRollbackForClassName：填写的参数是全类名

    ​ rollbackFor：哪些异常事务需要回滚

    ​ rollbackForClassName：填写的参数是全类名

    ​ readOnly：设置事务是否为只读事务

    ​ timeout：事务超出指定执行时长后自动终止并回滚,单位是秒

    4、测试超时属性

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(timeout = 3)
    public void checkout(String username,int id){

        bookDao.updateStock(id);
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }
}
    5、设置事务只读

    ​ 如果你一次执行单条查询语句，则没有必要启用事务支持，数据库默认支持SQL执行期间的读一致性；

    ​ 如果你一次执行多条查询语句，例如统计查询，报表查询，在这种场景下，多条查询SQL必须保证整体的读一致性，否则，在前条SQL查询之后，后条SQL查询之前，数据被其他用户改变，则该次整体的统计查询将会出现读数据不一致的状态，此时，应该启用事务支持。

    ​ 对于只读查询，可以指定事务类型为readonly，即只读事务。由于只读事务不存在数据的修改，因此数据库将会为只读事务提供一些优化手段

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(timeout = 3,readOnly = true)
    public void checkout(String username,int id){

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }
}
    6、设置哪些异常不回滚

    ​ 注意：运行时异常默认回滚，编译时异常默认不回滚

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(timeout = 3,noRollbackFor = {ArithmeticException.class,NullPointerException.class})
    public void checkout(String username,int id){

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
        int i = 1/0;
    }
    
        @Transactional(timeout = 3,noRollbackForClassName = {"java.lang.ArithmeticException"})
    public void checkout(String username,int id){

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
        int i = 1/0;
    }
}
    7、设置哪些异常回滚

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(timeout = 3,rollbackFor = {FileNotFoundException.class})
    public void checkout(String username,int id) throws FileNotFoundException {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
//        int i = 1/0;
        new FileInputStream("aaa.txt");
    }
}
    8、设置隔离级别

    ​ 隔离级别没有接触的同学可以看我之前的事务视频，里面有详细讲解，此处不再赘述。

    BookService.java

    package com.mashibing.service;

import com.mashibing.dao.BookDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Transactional;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(timeout = 3,isolation = Isolation.READ_COMMITTED)
    public void checkout(String username,int id) throws FileNotFoundException {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
//        int i = 1/0;
        new FileInputStream("aaa.txt");
    }
}
    9、事务的传播特性

    事务的传播特性指的是当一个事务方法被另一个事务方法调用时，这个事务方法应该如何进行？

    spring的事务传播行为一共有7种：

    image.png

    10、测试事务的传播特性

    BookDao.java

    package com.mashibing.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Repository;

@Repository
public class BookDao {

    @Autowired
    JdbcTemplate jdbcTemplate;

    /**
     * 减去某个用户的余额
     * @param userName
     * @param price
     */
    public void updateBalance(String userName,int price){
        String sql = "update account set balance=balance-? where username=?";
        jdbcTemplate.update(sql,price,userName);
    }

    /**
     * 按照图书的id来获取图书的价格
     * @param id
     * @return
     */
    public int getPrice(int id){
        String sql = "select price from book where id=?";
        return jdbcTemplate.queryForObject(sql,Integer.class,id);
    }

    /**
     * 减库存，减去某本书的库存
     * @param id
     */
    public void updateStock(int id){
        String sql = "update book_stock set stock=stock-1 where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改图书价格
     * @param id
     * @param price
     */
    public void updatePrice(int id,int price){
        String sql = "update book set price=? where id =?";
        jdbcTemplate.update(sql,price,id);
    }
}

    BookService.java

    package com.mashibing.service;

        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;
        import org.springframework.transaction.annotation.Isolation;
        import org.springframework.transaction.annotation.Propagation;
        import org.springframework.transaction.annotation.Transactional;

        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(propagation = Propagation.REQUIRED)
    public void checkout(String username,int id) {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }

    @Transactional(propagation = Propagation.REQUIRED)
    public void updatePrice(int id,int price){
        bookDao.updatePrice(id,price);
        int i = 1/0;
    }
}

    MulService.java

    package com.mashibing.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class MulService {

    @Autowired
    private BookService bookService;

    @Transactional
    public void mulTx(){
        bookService.checkout("zhangsan",1);
        bookService.updatePrice(1,1000);
    }
}

    MyTest.java

    import com.mashibing.service.MulService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("jdbcTemplate.xml");
        MulService mulService = context.getBean("mulService", MulService.class);
        mulService.mulTx();
    }
}

    通过上图的结果发现，如果设置的传播特性是Required，那么所有的事务都会统一成一个事务，一旦发生错误，所有的数据都要进行回滚。
    BookService.java

    package com.mashibing.service;

        import com.mashibing.dao.BookDao;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;
        import org.springframework.transaction.annotation.Isolation;
        import org.springframework.transaction.annotation.Propagation;
        import org.springframework.transaction.annotation.Transactional;

        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public void checkout(String username,int id) {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }

    @Transactional(propagation = Propagation.REQUIRED)
    public void updatePrice(int id,int price){
        bookDao.updatePrice(id,price);
        int i = 1/0;
    }
}

    通过修改checkout方法的传播特性为Required_new,发现价格进行了回滚，而其他的数据没有进行回滚。
    BookService.java

    package com.mashibing.service;

        import com.mashibing.dao.BookDao;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;
        import org.springframework.transaction.annotation.Isolation;
        import org.springframework.transaction.annotation.Propagation;
        import org.springframework.transaction.annotation.Transactional;

        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(propagation = Propagation.REQUIRED)
    public void checkout(String username,int id) {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }

    @Transactional(propagation = Propagation.REQUIRED)
    public void updatePrice(int id,int price){
        bookDao.updatePrice(id,price);
    }
}

    MulService.java

    package com.mashibing.service;

import com.mashibing.bean.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class MulService {

    @Autowired
    private BookService bookService;

    @Transactional
    public void mulTx(){
        bookService.checkout("zhangsan",1);
        bookService.updatePrice(1,1000);
        int i = 1/0;
    }
}

    将bookservice方法的传播行为为Required，并且将报错设置在MulService中，发现会都进行回滚。
    BookService.java

    package com.mashibing.service;

        import com.mashibing.dao.BookDao;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;
        import org.springframework.transaction.annotation.Isolation;
        import org.springframework.transaction.annotation.Propagation;
        import org.springframework.transaction.annotation.Transactional;

        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public void checkout(String username,int id) {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }

    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public void updatePrice(int id,int price){
        bookDao.updatePrice(id,price);
    }
}

    MulService.java

    package com.mashibing.service;

import com.mashibing.bean.Book;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

@Service
public class MulService {

    @Autowired
    private BookService bookService;

    @Transactional
    public void mulTx(){
        bookService.checkout("zhangsan",1);
        bookService.updatePrice(1,1000);
        int i = 1/0;
    }
}

    将bookservice方法的传播行为为Requires_new，并且将报错设置在MulService中，发现都不会进行回滚。
    BookService.java

    package com.mashibing.service;

        import com.mashibing.dao.BookDao;
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.stereotype.Service;
        import org.springframework.transaction.annotation.Isolation;
        import org.springframework.transaction.annotation.Propagation;
        import org.springframework.transaction.annotation.Transactional;

        import java.io.File;
        import java.io.FileInputStream;
        import java.io.FileNotFoundException;

@Service
public class BookService {

    @Autowired
    BookDao bookDao;

    /**
     * 结账：传入哪个用户买了哪本书
     * @param username
     * @param id
     */
    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public void checkout(String username,int id) {

        bookDao.updateStock(id);
        int price = bookDao.getPrice(id);
        bookDao.updateBalance(username,price);
    }

    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public void updatePrice(int id,int price){
        bookDao.updatePrice(id,price);
    }

    @Transactional
    public void mulTx(){
        checkout("zhangsan",1);
        updatePrice(1,1000);
        int i = 1/0;
    }
}

    如果在bookservice执行的话，会发现刚刚的效果就没有了，原因是外层调用的时候使用的AOP，但是本类方法自己的调用就是最最普通的调用，就是同一个事务。

    总结：
    1、事务传播级别是REQUIRED，当checkout()被调用时（假定被另一类中commit()调用），如果checkout()中的代码抛出异常，即便被捕获，commit()中的其他代码都会roll back

    2、是REQUIRES_NEW，如果checkout()中的代码抛出异常，并且被捕获，commit()中的其他代码不会roll back；如果commit()中的其他代码抛出异常，而且没有捕获，不会导致checkout()回滚

    3、是NESTED，如果checkout()中的代码抛出异常，并且被捕获，commit()中的其他代码不会roll back；如果commit()中的其他代码抛出异常，而且没有捕获，会导致checkout()回滚

    PROPAGATION_REQUIRES_NEW 启动一个新的, 不依赖于环境的 "内部" 事务. 这个事务将被完全 commited 或 rolled back 而不依赖于外部事务, 它拥有自己的隔离范围, 自己的锁, 等等. 当内部事务开始执行时, 外部事务将被挂起, 内务事务结束时, 外部事务将继续执行. 
另一方面, PROPAGATION_NESTED 开始一个 "嵌套的" 事务,  它是已经存在事务的一个真正的子事务. 嵌套事务开始执行时,  它将取得一个 savepoint. 如果这个嵌套事务失败, 我们将回滚到此 savepoint. 潜套事务是外部事务的一部分, 只有外部事务结束后它才会被提交. 
由此可见, PROPAGATION_REQUIRES_NEW 和 PROPAGATION_NESTED 的最大区别在于, PROPAGATION_REQUIRES_NEW 完全是一个新的事务, 而 PROPAGATION_NESTED 则是外部事务的子事务, 如果外部事务 commit, 嵌套事务也会被 commit, 这个规则同样适用于 roll back. 
### 3、基于xml的事务配置

    jdbcTemplate.xml

    <?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:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx"
       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/aop
       https://www.springframework.org/schema/aop/spring-aop.xsd
       http://www.springframework.org/schema/tx
       https://www.springframework.org/schema/tx/spring-tx.xsd
">
    <context:component-scan base-package="com.mashibing"></context:component-scan>
    <context:property-placeholder location="classpath:dbconfig.properties"></context:property-placeholder>
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="driverClassName" value="${jdbc.driverClassName}"></property>
    </bean>
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource"></constructor-arg>
    </bean>
    <bean id="namedParameterJdbcTemplate" class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg name="dataSource" ref="dataSource"></constructor-arg>
    </bean>
    <!--事务控制-->
    <!--配置事务管理器的bean-->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!--
    基于xml配置的事务：依赖tx名称空间和aop名称空间
        1、spring中提供事务管理器（切面），配置这个事务管理器
        2、配置出事务方法
        3、告诉spring哪些方法是事务方法（事务切面按照我们的切入点表达式去切入事务方法）
    -->
    <bean id="bookService" class="com.mashibing.service.BookService"></bean>
    <aop:config>
        <aop:pointcut id="txPoint" expression="execution(* com.mashibing.service.*.*(..))"/>
        <!--事务建议：advice-ref:指向事务管理器的配置-->
        <aop:advisor advice-ref="myAdvice" pointcut-ref="txPoint"></aop:advisor>
    </aop:config>
    <tx:advice id="myAdvice" transaction-manager="transactionManager">
        <!--事务属性-->
        <tx:attributes>
            <!--指明哪些方法是事务方法-->
            <tx:method name="*"/>
            <tx:method name="checkout" propagation="REQUIRED"/>
            <tx:method name="get*" read-only="true"></tx:method>
        </tx:attributes>
    </tx:advice>
</beans>
    javaspringtransaction
    萌妹子_liu
    28 声望43 粉丝

    萌萌哒，程序猿

    « 上一篇
    spring基础之四->Spring AOP介绍与使用
    下一篇 »
    Spring基础之六->Spring原理讲解

    引用和评论

    推荐阅读
    头像
    mybatis基础之二->Mybatis SQL映射文件详解

    萌妹子_liu赞 1阅读 1.2k

    头像
    在Java程序中监听mysql的binlog

    huan1993赞 7阅读 1k

    头像
    Activiti7实战笔记

    Corwien赞 4阅读 11k

    头像
    Just for fun——迅速写完快速排序

    ufdf赞 3阅读 2.3k

    头像
    Spring和idea为什么不推荐使用@Autowired注入

    kexb赞 7阅读 1.3k评论 1

    头像
    Spring 实现 3 种异步流式接口，干掉接口超时烦恼

    程序员小富赞 3阅读 1k

    头像
    MySQL 亿级数据平滑迁移实战

    vivo互联网技术赞 2阅读 812

    0 条评论
    得票最新