DAO跨事物调用---转账

第一步创建实体类：Entity

 package com.beiwo.epet.entity;

 public class Account {
     private int id;

     private String name;

     private int money;

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getMoney() {
         return money;
     }

     public void setMoney(int money) {
         this.money = money;
     }

 }

第二步：基类接口和实现基类接口：Account AccountDaoImpl

 package com.beiwo.epet.dao;

 import com.beiwo.epet.entity.Account;

 public interface  AccountDao {

     public void updateAccount(String fromName,String toName,int money)throws Exception;

     public void updateAccount(Account account)throws Exception;

     public Account findAccountByName(String name)throws Exception;
 }

 package com.beiwo.epet.dao.impl;

 import org.apache.commons.dbutils.QueryRunner;
 import org.apache.commons.dbutils.handlers.BeanHandler;

 import com.beiwo.epet.dao.AccountDao;
 import com.beiwo.epet.entity.Account;
 import com.beiwo.epet.util.C3P0Util;
 import com.beiwo.epet.util.TransactionManager;

 public class AccountDaoImpl implements AccountDao{

     @Override
     public void updateAccount(String fromName, String toName, int money) throws Exception{
         QueryRunner qr=new QueryRunner(C3P0Util.getDataSource());

         qr.update("UPDATE account SET money=money-? WHERE name=?",money,fromName);
         qr.update("UPDATE account SET money=money+? WHERE name=?",money,toName);
     }

     @Override
     public void updateAccount(Account account) throws Exception{
         QueryRunner qr=new QueryRunner();
         qr.update(TransactionManager.getConnection(),"UPDATE account SET money=? WHERE name=?", account.getMoney(),account.getName());
     }

     @Override
     public Account findAccountByName(String name) throws Exception{
         QueryRunner qr=new QueryRunner();
         return qr.query(TransactionManager.getConnection(),"SELECT * FROM account WHERE name=?",new BeanHandler<Account>(Account.class),name);

     }

 }

第三步：业务逻辑接口和业务逻辑的实现：AccountService  AccountServiceImply

 package com.beiwo.epet.service;

 public interface AccountService {

     public void transfer(String formName,String toName,int money);

 }

 package com.beiwo.epet.service.impl;

 import com.beiwo.epet.dao.AccountDao;
 import com.beiwo.epet.dao.impl.AccountDaoImpl;
 import com.beiwo.epet.entity.Account;
 import com.beiwo.epet.service.AccountService;
 import com.beiwo.epet.util.TransactionManager;

 public class AccountServiceImpl implements AccountService{

     @Override
     public void transfer(String formName, String toName, int money) {
         AccountDao accountDao=new AccountDaoImpl(); 

         try {
             ///开始一个事务,start transaction;
             //获取转入和转出的账户对象
             TransactionManager.startTransaction();

             Account fromAccount=accountDao.findAccountByName(formName);
             Account toAccount=accountDao.findAccountByName(toName);

             //修改账户的各自金额
             fromAccount.setMoney(fromAccount.getMoney()-money);
             toAccount.setMoney(toAccount.getMoney()+money);

             //完成转账的操作
             accountDao.updateAccount(fromAccount);

             int i=2/0;

             accountDao.updateAccount(toAccount);

             TransactionManager.commitTransaction();

         } catch (Exception e) {
             try {
                 TransactionManager.rollbackTransaction();;//事务的回滚
             } catch (Exception e2) {
                 e2.printStackTrace();
             }

         }finally{
             try {
                 TransactionManager.close();
             } catch (Exception e2) {
                 e2.printStackTrace();
             }
         }

     }

 }

第四步：测试类 TesTransfer

 package com.beiwo.epet.test;

 import org.junit.Test;

 import com.beiwo.epet.service.AccountService;
 import com.beiwo.epet.service.impl.AccountServiceImpl;

 public class TestTransfer {

     @Test
     public void test(){
         AccountService accountService=new AccountServiceImpl();

         accountService.transfer("aaa", "bbb", 100);

     }
 }

数据库的建立：