缺點：Service層面把Dao層面的開啟事務操作完成了

1.自行創建C3P0Uti，account數據庫，導入Jar包

2.Dao層面

?接口：

package com.learning.dao;import com.learning.domain.Account;public interface AccountDao {/*** 轉賬* @param fromname 轉出用戶* @param toname 轉入用戶* @param money 轉賬金額*/@Deprecatedpublic void updateAccount(String fromname,String toname,double money)throws Exception;/*** 根據賬戶信息修改金額* @param accout*/public void updateAccout(Account accout) throws Exception;/*** 根據用戶名查找賬戶信息* @param name* @return* @throws Exception*/public Account findAccountByName(String name)throws Exception; }

實現類：

package com.learning.dao.impl;import java.sql.Connection; import java.sql.SQLException;import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler;import com.learning.dao.AccountDao; import com.learning.domain.Account; import com.learning.util.C3P0Util;public class AccountDaoImpl implements AccountDao {private Connection conn;public AccountDaoImpl(Connection conn) {this.conn = conn;}public void updateAccount(String fromname, String toname, double money) throws Exception {//創建一個QueryRunner對象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);}public void updateAccout(Account account) throws Exception {QueryRunner qr = new QueryRunner();qr.update(conn,"update account set money=? where name=?",account.getMoney(),account.getName());}public Account findAccountByName(String name) throws Exception {QueryRunner qr = new QueryRunner();return qr.query(conn,"select * from account where name=?", new BeanHandler<Account>(Account.class),name);}}

3.Service層面

接口：

package com.learning.service;public interface AccountService {/*** 轉賬* @param fromname 轉出用戶* @param toname 轉入用戶* @param money 轉賬金額*/public void transfer(String fromname,String toname,double money); }

實現類：

package com.learning.service.impl;import java.sql.Connection; import java.sql.SQLException;import com.learning.dao.AccountDao; import com.learning.dao.impl.AccountDaoImpl; import com.learning.domain.Account; import com.learning.service.AccountService; import com.learning.util.C3P0Util;public class AccountServiceImpl implements AccountService {public void transfer(String fromname, String toname, double money) {// ad.updateAccount(fromname, toname, money);Connection conn = C3P0Util.getConnection();AccountDao ad = new AccountDaoImpl(conn);try {conn.setAutoCommit(false);//begin//分別得到轉出和轉入賬戶對象Account fromAccount = ad.findAccountByName(fromname);Account toAccount = ad.findAccountByName(toname);//修改賬戶各自的金額fromAccount.setMoney(fromAccount.getMoney()-money);toAccount.setMoney(toAccount.getMoney()+money);//完成轉賬操作 ad.updateAccout(fromAccount); // int i = 10/0; ad.updateAccout(toAccount);conn.commit();//提交事務} catch (Exception e) {try {conn.rollback();//回滾事務} catch (SQLException e1) {e1.printStackTrace();} }finally{try {conn.close();} catch (SQLException e) {e.printStackTrace();}//關閉 }}}

?

轉載于:https://www.cnblogs.com/youwillsee/p/6664848.html

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