实现购买股票案例：
一、引入JAR文件：
二、开始搭建分层架构---创建账户(Account)和股票(Stock)实体类
Account:
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/* * 账户 */public class Account { private int aid;//账户编号 private String aname;//账户名称 private double balance;//账户金额 public int getAid() { return aid; } public void setAid(int 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; } |
Stock：
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/* * 股票 */public class Stock {private int sid;//股票编号private String sname;//名称private int count;//股数public int getSid() { return sid;}public void setSid(int 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;}} |
三、创建Dao层，定义账户以及股票的接口，自定义新增和修改的方法，实现类实现该接口，重写方法
IAccountDao：
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public interface IAccountDao { //添加账户 public int addAccount(Account account); //修改账户 public int updateAccount(int aid,int money,boolean isBuyOrNot);<br> |
//查询余额
public int selectMoney(int aid);
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} |
IStockDao：
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public interface IStockDao { //添加股票 public int addStock(Stock stock); //修改股票 public int updateStock(int aid,int num,boolean isBuyOrNot);} |
AccountDaoImpl:实现类。继承自JdbcDaoSupport并实现IAccountDao接口，在这里需要用到JDBC模板的getJdbcTemplate()，通过该方法实现对SQL语句增删改查。
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public class AccountDaoImpl extends JdbcDaoSupport implements IAccountDao{ //添加 public int addAccount(Account account) { String sql="insert into account(aid,aname,balance) values(?,?,?)"; int count=this.getJdbcTemplate().update(sql, account.getAid(),account.getAname(),account.getBalance()); return count; } //修改 public int updateAccount(int aid, int money, boolean isBuyOrNot) { String sql=null; if(isBuyOrNot){ sql="update account set balance=balance-? where aid=?"; } else{ sql="update account set balance=balance+? where aid=?"; } int count=this.getJdbcTemplate().update(sql, money,aid); return count; } |
StockDaoImpl：实现类同理
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public class StockDaoImpl extends JdbcDaoSupport implements IStockDao{ //添加股票 public int addStock(Stock stock) { String sql="insert into stock(sid,sname,count) values(?,?,?)"; int count=this.getJdbcTemplate().update(sql, stock.getSid(),stock.getSname(),stock.getCount()); return count; } //修改 public int updateStock(int aid, int num, boolean isBuyOrNot) { String sql=null; if(isBuyOrNot){ sql="update stock set count=count+? where sid=?"; } else{ sql="update stock set count=count-? where sid=?"; } int count=this.getJdbcTemplate().update(sql, num,aid); return count; } |
四、业务逻辑层：service
定义接口IStockService,并实现添加账户，股票，以及购买股票的方法.购买股票需要传入账户的id,股票的id。以及金额，股数
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public interface IStockService { //添加账户 public int addAccount(Account account); //添加股票 public int addStock(Stock stock); //购买股票 public void buyStock(int aid,int money,int sid,int num) throws StockException;} |
实现类：StockServiceImpl。重写方法。并植入Dao。以及自定义StockException异常，用于判定用户的余额小于0，抛出异常
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public class StockServiceImpl implements IStockService{ //植入dao private IAccountDao accountDao; private IStockDao stockDao; //添加账户 public int addAccount(Account account) { return accountDao.addAccount(account); } //添加股票 public int addStock(Stock stock) { return stockDao.addStock(stock); } //购买一股票 public void buyStock(int aid, int money, int sid, int num) throws StockException { boolean isBuy=true; accountDao.updateAccount(aid, money, isBuy); if(accountDao.selectMoney(aid)<=0){ throw new StockException("捕获异常！！！"); } stockDao.updateStock(aid, num, isBuy); } |
五、Spring配置文件。[重点]
方式一:通过事务代理工厂bean进行配置[XML方式]
①引入一系列的约束头文件以及标签
②配置C3P0数据源以及DAO、Service
③配置事务管理器以及事务代理工厂Bean。测试类getBean获取的是代理工厂id
方式二：注解。测试类getBean获取的id是原始对象service
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<!-- 注解 --> <tx:annotation-driven transaction-manager="mytx"/> |
方式三：Aspectj AOP配置事务 。同理 测试类getBean方法id获取的是原始对象
测试类：
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public class Test01 {@Testpublic void addTest() throws StockException{ ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml"); IStockService service = (IStockService)ctx.getBean("stockService"); service.buyStock(1, 800, 1, 2);} |