實現購買股票案例：
一、引入JAR文件：
二、開始搭建分層架構---創建賬戶(Account)和股票(Stock)實體類
Account:
/*
* 賬戶
*/
public class Account {
private int aid;//賬戶編號
private String aname;//賬戶名稱
private double balance;//賬戶金額
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：
/*
* 股票
*/
public class Stock {
private int sid;//股票編號
private String sname;//名稱
private int count;//股數
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、創建Dao層，定義賬戶以及股票的接口，自定義新增和修改的方法，實現類實現該接口，重寫方法
IAccountDao：
public interface IAccountDao {
//添加賬戶
public int addAccount(Account account);
//修改賬戶
public int updateAccount(int aid,int money,boolean isBuyOrNot);
//查詢余額
public int selectMoney(int aid);
}
IStockDao：
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:實現類。繼承自JdbcDaoSupport並實現IAccountDao接口，在這里需要用到JDBC模板的getJdbcTemplate()，通過該方法實現對SQL語句增刪改查。
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：實現類同理
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、業務邏輯層：service
定義接口IStockService,並實現添加賬戶，股票，以及購買股票的方法.購買股票需要傳入賬戶的id,股票的id。以及金額，股數
public interface IStockService {
//添加賬戶
public int addAccount(Account account);
//添加股票
public int addStock(Stock stock);
//購買股票
public void buyStock(int aid,int money,int sid,int num) throws StockException;
}
實現類：StockServiceImpl。重寫方法。並植入Dao。以及自定義StockException異常，用於判定用戶的余額小於0，拋出異常
public class StockServiceImpl implements IStockService{
//植入dao
private IAccountDao accountDao;
private IStockDao stockDao;
//添加賬戶
public int addAccount(Account account) {
return accountDao.addAccount(account);
}
//添加股票
public int addStock(Stock stock) {
return stockDao.addStock(stock);
}
//購買一股票
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("捕獲異常！！！");
}
stockDao.updateStock(aid, num, isBuy);
}
五、Spring配置文件。[重點]
方式一:通過事務代理工廠bean進行配置[XML方式]
①引入一系列的約束頭文件以及標簽
②配置C3P0數據源以及DAO、Service
③配置事務管理器以及事務代理工廠Bean。測試類getBean獲取的是代理工廠id
方式二：注解。測試類getBean獲取的id是原始對象service
<!-- 注解 --> <tx:annotation-driven transaction-manager="mytx"/>
方式三：Aspectj AOP配置事務 。同理 測試類getBean方法id獲取的是原始對象
測試類：
public class Test01 {
@Test
public void addTest() throws StockException{
ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");
IStockService service = (IStockService)ctx.getBean("stockService");
service.buyStock(1, 800, 1, 2);
}