2018-05-08

spring

第十章 Spring事务管理

10.1 事务管理器接口

事务管理器是PlatformTransactionManager接口对象。其主要用于完成事务的提交、回滚及获取事务的状态信息。

常用的两个实现类

DataSourceTransactionManager：使用JDBC或iBatis进行持久化数据时使用。
HibernateTransactionManager：使用Hibernate进行持久化数据时使用。

Spring的回滚方式

Spring事务的默认回滚方式是：发生运行异常时回滚，发生受查异常时提交。

运行异常指的是继承自RuntimeException的异常类，受查异常指的是继承自Exception的异常类。

10.2 事务定义接口

TransactionDefinition

隔离级别：

static int ISOLATION_DEFAULT 0
static int ISOLATION_READ_COMMITTED 2
static int ISOLATION_READ_UNCOMMITED 1
static int ISOLATION_REPEATABLE_READ 4
static int ISOLATION_SERIALIZABLE 8

MYSQL默认的是可重复读，ORACLE默认的是读已提交

事务的传播行为

定义了七个事务传播行为。

doSome()方法调用doOther()方法，或doSome()方法存在于事务中，则doOther()方法加入到该事务中执行；若doSome()方法在调用doOther()方法时没有在事务内执行，则doOther()方法会创建一个事务，并在其中执行。

10.3 程序举例

两个实体：银行账户Account与股票账户Stock。当要购买股票时，从Account中扣除相应金额的存款，同时在Stock中增加相应的股票数量。在这个过程中，抛出一个用户自定义的异常，使两个操作回滚。

10.4 定义实体及DB表

Account.java

package com.bjpowernode.beans;

public class Account {
    private Integer aid;
    private String aname;
    private double balance;
    public Account() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Account(String aname, double balance) {
        super();
        this.aname = aname;
        this.balance = balance;
    }
    public Integer getAid() {
        return aid;
    }
    public void setAid(Integer aid) {
        this.aid = aid;
    }
    public String getAname() {
        return aname;
    }
    public void setAname(String aname) {
        this.aname = aname;
    }
    public double getBalance() {
        return balance;
    }
    public void setBalance(double balance) {
        this.balance = balance;
    }
    @Override
    public String toString() {
        return "Account [aid=" + aid + ", aname=" + aname + ", balance=" + balance + "]";
    }

}

Stock.java

package com.bjpowernode.beans;

public class Stock {
    private Integer sid;
    private String sname;
    private int count;

    public Stock() {
        super();
        // TODO Auto-generated constructor stub
    }

    public Stock(String sname, int count) {
        super();
        this.sname = sname;
        this.count = count;
    }

    public Integer getSid() {
        return sid;
    }

    public void setSid(Integer sid) {
        this.sid = sid;
    }

    public String getSname() {
        return sname;
    }

    public void setSname(String sname) {
        this.sname = sname;
    }

    public int getCount() {
        return count;
    }

    public void setCount(int count) {
        this.count = count;
    }

    @Override
    public String toString() {
        return "Stock [sid=" + sid + ", sname=" + sname + ", count=" + count + "]";
    }

}

10.5 定义service

业务接口

package com.bjpowernode.service;

public interface IBuyStockService {
    void openAccount(String aname, double money);
    void openStock(String sname, int amount);
    void buyStock(String aname, double money, String sname, int amount) throws BuyStockException;
}

业务实现类

package com.bjpowernode.service;

import com.bjpowernode.Dao.IAccountDao;
import com.bjpowernode.Dao.IStockDao;

public class BuyStockServiceImpl implements IBuyStockService {
    private IAccountDao adao;
    private IStockDao sdao;

    public void setAdao(IAccountDao adao) {
        this.adao = adao;
    }

    public void setSdao(IStockDao sdao) {
        this.sdao = sdao;
    }

    @Override
    public void openAccount(String aname, double money) {
        adao.insertAccount(aname, money);
    }

    @Override
    public void openStock(String sname, int amount) {
        sdao.insertStock(sname, amount);
    }

    @Override
    public void buyStock(String aname, double money, String sname, int amount) throws BuyStockException {
        boolean isBuy = true;
        adao.updateAccount(aname, money, isBuy);
        if(true) {
            throw new BuyStockException("购买股票异常");
        }
        sdao.updateStock(sname, amount, isBuy);
    }

}

10.6 定义Dao

IAccountDao

package com.bjpowernode.Dao;

public interface IAccountDao {

    void insertAccount(String aname, double money);

    void updateAccount(String aname, double money, boolean isBuy);

}

AccountDaoImpl

package com.bjpowernode.Dao;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao {

    @Override
    public void insertAccount(String aname, double money) {
        String sql = "insert into account(aname, balance) values(?,?)";
        this.getJdbcTemplate().update(sql, aname, money);
    }

    @Override
    public void updateAccount(String aname, double money, boolean isBuy) {
        String sql = "update account set balance = balance + ? where aname=?";
        if(isBuy) {
            sql = "update account set balance = balance - ? where aname=?";
        }
        this.getJdbcTemplate().update(sql, money, aname);
    }

}

IStockDao

package com.bjpowernode.Dao;

public interface IStockDao {

    void insertStock(String sname, int amount);

    void updateStock(String sname, int amount, boolean isBuy);

}

StockDaoImpl

package com.bjpowernode.Dao;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class StockDaoImpl extends JdbcDaoSupport implements IStockDao {

    @Override
    public void insertStock(String sname, int amount) {
        String sql = "insert into stock(sname, count) values(?,?)";
        this.getJdbcTemplate().update(sql, sname, amount);
    }

    @Override
    public void updateStock(String sname, int amount, boolean isBuy) {
        String sql = "update stock set count = count-? where sname=?";
        if(isBuy) {
            sql = "update stock set count = count+? where sname=?";            
        }
        this.getJdbcTemplate().update(sql, amount, sname);
    }

}

10.7 定义测试类

MyTest.java

package com.bjpowernode.test;

import java.nio.channels.AcceptPendingException;
import java.util.List;

import org.junit.Before;
import org.junit.Test;
import org.springframework.cache.support.AbstractCacheManager;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.dao.support.DaoSupport;

import com.bjpowernode.service.BuyStockException;
import com.bjpowernode.service.IBuyStockService;


public class MyTest {

    private IBuyStockService service;

    @Before
    public void before() {
        String source = "applicationContext.xml";
        ApplicationContext ac = new ClassPathXmlApplicationContext(source);
        service = (IBuyStockService) ac.getBean("buyStockService");
    }

    @Test
    public void test01() {
        service.openAccount("张三", 10000);
        service.openStock("动力节点", 0);
    }    

    @Test
    public void test02() {
        try {
            service.buyStock("张三", 2000, "动力节点", 5);
        } catch (BuyStockException e) {
            e.printStackTrace();
        }
    }    

}

10.8 异常类

package com.bjpowernode.service;

public class BuyStockException extends Exception {

    public BuyStockException() {
        super();
    }

    public BuyStockException(String message) {
        super(message);
    }

}

10.9 注册

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"
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
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd">

    <!-- 注册属性文件：从属性文件读取DB连接四要素：方式二 -->
    <context:property-placeholder location="classpath:jdbc.properties"/>

    <!-- 注册数据源:Spring内置的连接池 -->
    <bean id="myDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="${jdbc.driver}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="username" value="${jdbc.user}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean>

    <!-- 注册dao -->
    <bean id="accountDao" class="com.bjpowernode.Dao.AccountDaoImpl">
        <property name="dataSource" ref="myDataSource"></property>
    </bean>

    <bean id="stockDao" class="com.bjpowernode.Dao.StockDaoImpl">
        <property name="dataSource" ref="myDataSource"></property>
    </bean>

    <!-- 注册service -->
    <bean id="buyStockService" class="com.bjpowernode.service.BuyStockServiceImpl">
        <property name="adao" ref="accountDao"></property>
        <property name="sdao" ref="stockDao"></property>
    </bean>

<!-- ============================ AOP ===================================================  -->

    <!-- 注册事务管理器 -->
    <bean id="myTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="myDataSource"></property>
    </bean>

    <!-- 注册事务通知 -->
    <tx:advice id="txAdvice" transaction-manager="myTransactionManager">
        <tx:attributes>
            <!-- 这里指定的是：为每一个连接点指定所要应用的事务属性 -->
            <tx:method name="open*" isolation="DEFAULT" propagation="REQUIRED"/>
            <tx:method name="buyStock" isolation="DEFAULT" propagation="REQUIRED" rollback-for="BuyStockException"/>
        </tx:attributes>
    </tx:advice>

    <aop:config>
        <!-- 这里指定的是切入点 -->
        <aop:pointcut expression="execution(* *..service.*.buyStock(..))" id="myPointcut"/>
        <aop:advisor advice-ref="txAdvice" pointcut-ref="myPointcut"/>    
    </aop:config>

</beans>