获取连接的工具类
连接的工具类，它用于从数据源中获取一个连接，并且实现和线程的绑定和解绑：ThreadLocal
- 有多个连接时无法控制事务
代码：
package cn.luis.utils;
import javax.sql.DataSource;
import java.sql.Connection;
/**
*
*/
public class ConnectionUtils {
private ThreadLocal<Connection> tl = new ThreadLocal<Connection>();
private DataSource dataSource;
public void setDataSource(DataSource dataSource) {
this.dataSource = dataSource;
}
/**
* 获取当前线程上的连接
* @return
*/
public Connection getThreadConnection() {
try{
//1.先从ThreadLocal上获取
Connection conn = tl.get();
//2.判断当前线程上是否有连接
if (conn == null) {
//3.从数据源中获取一个连接，并且存入ThreadLocal中
conn = dataSource.getConnection();
tl.set(conn);
}
//4.返回当前线程上的连接
return conn;
}catch (Exception e){
throw new RuntimeException(e);
}
}
/**
* 把连接和线程解绑
*/
public void removeConnection(){
tl.remove();
}
}
事务管理工具类
和事务管理相关的工具类，它包含了，开启事务，提交事务，回滚事务和释放连接
代码：
package cn.luis.utils;
public class TransactionManager {
private ConnectionUtils connectionUtils;
public void setConnectionUtils(ConnectionUtils connectionUtils) {
this.connectionUtils = connectionUtils;
}
/**
* 开启事务
*/
public void beginTransaction(){
try {
connectionUtils.getThreadConnection().setAutoCommit(false);
}catch (Exception e){
e.printStackTrace();
}
}
/**
* 提交事务
*/
public void commit(){
try {
connectionUtils.getThreadConnection().commit();
}catch (Exception e){
e.printStackTrace();
}
}
/**
* 回滚事务
*/
public void rollback(){
try {
connectionUtils.getThreadConnection().rollback();
}catch (Exception e){
e.printStackTrace();
}
}
/**
* 释放连接
*/
public void release(){
try {
connectionUtils.getThreadConnection().close();//还回连接池中
connectionUtils.removeConnection();
}catch (Exception e){
e.printStackTrace();
}
}
}
编写业务层和持久层事务控制代码
业务层
package cn.luis.service.impl;
import cn.luis.dao.IAccountDao;
import cn.luis.domain.Account;
import cn.luis.service.IAccountService;
import cn.luis.utils.TransactionManager;
import java.util.List;
/**
* 账户的业务层实现类
*
* 事务控制应该都是在业务层
*/
public class AccountServiceImpl_OLD implements IAccountService {
private IAccountDao accountDao;
private TransactionManager txManager;
public void setTxManager(TransactionManager txManager) {
this.txManager = txManager;
}
public void setAccountDao(IAccountDao accountDao) {
this.accountDao = accountDao;
}
@Override
public List<Account> findAllAccount() {
try {
//1.开启事务
txManager.beginTransaction();
//2.执行操作
List<Account> accounts = accountDao.findAllAccount();
//3.提交事务
txManager.commit();
//4.返回结果
return accounts;
}catch (Exception e){
//5.回滚操作
txManager.rollback();
throw new RuntimeException(e);
}finally {
//6.释放连接
txManager.release();
}
}
@Override
public Account findAccountById(Integer accountId) {
try {
//1.开启事务
txManager.beginTransaction();
//2.执行操作
Account account = accountDao.findAccountById(accountId);
//3.提交事务
txManager.commit();
//4.返回结果
return account;
}catch (Exception e){
//5.回滚操作
txManager.rollback();
throw new RuntimeException(e);
}finally {
//6.释放连接
txManager.release();
}
}
@Override
public void saveAccount(Account account) {
try {
//1.开启事务
txManager.beginTransaction();
//2.执行操作
accountDao.saveAccount(account);
//3.提交事务
txManager.commit();
}catch (Exception e){
//4.回滚操作
txManager.rollback();
}finally {
//5.释放连接
txManager.release();
}
}
@Override
public void updateAccount(Account account) {
try {
//1.开启事务
txManager.beginTransaction();
//2.执行操作
accountDao.updateAccount(account);
//3.提交事务
txManager.commit();
}catch (Exception e){
//4.回滚操作
txManager.rollback();
}finally {
//5.释放连接
txManager.release();
}
}
@Override
public void deleteAccount(Integer acccountId) {
try {
//1.开启事务
txManager.beginTransaction();
//2.执行操作
accountDao.deleteAccount(acccountId);
//3.提交事务
txManager.commit();
}catch (Exception e){
//4.回滚操作
txManager.rollback();
}finally {
//5.释放连接
txManager.release();
}
}
@Override
public void transfer(String sourceName, String targetName, Float money) {
try {
//1.开启事务
txManager.beginTransaction();
//2.执行操作
//2.1根据名称查询转出账户
Account source = accountDao.findAccountByName(sourceName);
//2.2根据名称查询转入账户
Account target = accountDao.findAccountByName(targetName);
//2.3转出账户减钱
source.setMoney(source.getMoney()-money);
//2.4转入账户加钱
target.setMoney(target.getMoney()+money);
//2.5更新转出账户
accountDao.updateAccount(source);
int i=1/0;
//2.6更新转入账户
accountDao.updateAccount(target);
//3.提交事务
txManager.commit();
}catch (Exception e){
//4.回滚操作
txManager.rollback();
e.printStackTrace();
}finally {
//5.释放连接
txManager.release();
}
}
}
持久层实现类
不要在QueryRunner中直接注入连接，改为在runner方法中传入和线程绑定过的"连接"。
代码：
package cn.luis.dao.impl;
import cn.luis.dao.IAccountDao;
import cn.luis.domain.Account;
import cn.luis.utils.ConnectionUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import java.util.List;
/**
* 账户的持久层实现类
*/
public class AccountDaoImpl implements IAccountDao {
private QueryRunner runner;
private ConnectionUtils connectionUtils;
public void setRunner(QueryRunner runner) {
this.runner = runner;
}
public void setConnectionUtils(ConnectionUtils connectionUtils) {
this.connectionUtils = connectionUtils;
}
@Override
public List<Account> findAllAccount() {
try{
return runner.query(connectionUtils.getThreadConnection(),"select * from account",new BeanListHandler<Account>(Account.class));
}catch (Exception e) {
throw new RuntimeException(e);
}
}
@Override
public Account findAccountById(Integer accountId) {
try{
return runner.query(connectionUtils.getThreadConnection(),"select * from account where id = ? ",new BeanHandler<Account>(Account.class),accountId);
}catch (Exception e) {
throw new RuntimeException(e);
}
}
@Override
public void saveAccount(Account account) {
try{
runner.update(connectionUtils.getThreadConnection(),"insert into account(name,money)values(?,?)",account.getName(),account.getMoney());
}catch (Exception e) {
throw new RuntimeException(e);
}
}
@Override
public void updateAccount(Account account) {
try{
runner.update(connectionUtils.getThreadConnection(),"update account set name=?,money=? where id=?",account.getName(),account.getMoney(),account.getId());
}catch (Exception e) {
throw new RuntimeException(e);
}
}
@Override
public void deleteAccount(Integer accountId) {
try{
runner.update(connectionUtils.getThreadConnection(),"delete from account where id=?",accountId);
}catch (Exception e) {
throw new RuntimeException(e);
}
}
@Override
public Account findAccountByName(String accountName) {
try{
List<Account> accounts = runner.query(connectionUtils.getThreadConnection(),"select * from account where name = ? ",new BeanListHandler<Account>(Account.class),accountName);
if(accounts == null || accounts.size() == 0){
return null;
}
if(accounts.size() > 1){
throw new RuntimeException("结果集不唯一，数据有问题");
}
return accounts.get(0);
}catch (Exception e) {
throw new RuntimeException(e);
}
}
}
配置spring的IOC
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<!-- 配置Service -->
<bean id="accountService" class="cn.luis.service.impl.AccountServiceImpl">
<!-- 注入dao -->
<property name="accountDao" ref="accountDao"></property>
<!--注入事务管理器-->
<property name="txManager" ref="txManager"></property>
</bean>
<!--配置Dao对象-->
<bean id="accountDao" class="cn.luis.dao.impl.AccountDaoImpl">
<!-- 注入QueryRunner -->
<property name="runner" ref="runner"></property>
<!-- 注入ConnectionUtils -->
<property name="connectionUtils" ref="connectionUtils"></property>
</bean>
<!--配置QueryRunner-->
<bean id="runner" class="org.apache.commons.dbutils.QueryRunner" scope="prototype"></bean>
<!-- 配置数据源 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<!--连接数据库的必备信息-->
<property name="driverClass" value="com.mysql.jdbc.Driver"></property>
<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/eesy"></property>
<property name="user" value="root"></property>
<property name="password" value="root"></property>
</bean>
<!-- 配置Connection的工具类 ConnectionUtils -->
<bean id="connectionUtils" class="cn.luis.utils.ConnectionUtils">
<!-- 注入数据源-->
<property name="dataSource" ref="dataSource"></property>
</bean>
<!-- 配置事务管理器-->
<bean id="txManager" class="cn.luis.utils.TransactionManager">
<!-- 注入ConnectionUtils -->
<property name="connectionUtils" ref="connectionUtils"></property>
</bean>
</beans>
