Spring Learning-DAY13

Demand:

Users purchase books, purchase success, inventory updates, account balance updates, if the balance or inventory is not enough, can not buy success, resulting in abnormal

Data sheet:

Account: List of accounts (including user name and balance)
Book: Books table (ID, title, book price)
Book_stock: Inventory table (ID, book inventory)

Code implementation:

1. Interface for book purchase

package com.atguigu.spring.tx;public interface BookShopDao {    //根据书号获取书的单价    public int findBookPriceByIsbn(String isbn);    //更新书的库存, 使书号对应的库存 - 1    public void updateBookStock(String isbn);    //更新用户的账户余额: 使 username 的 balance - price    public void updateUserAccount(String username, int price);}

Package Com.atguigu.spring.tx;import Org.springframework.beans.factory.annotation.autowired;import Org.springframework.jdbc.core.jdbctemplate;import org.springframework.stereotype.Repository; @Repository ("    Bookshopdao ") public class Bookshopdaoimpl implements Bookshopdao {@Autowired private jdbctemplate jdbctemplate;        @Override public int Findbookpricebyisbn (string ISBN) {String sql = "Select Price from book where ISBN =?";    return jdbctemplate.queryforobject (SQL, Integer.class, ISBN); } @Override public void Updatebookstock (string ISBN) {//Check the inventory is sufficient, if not enough, throws an exception String sql2 = "Select        Stock from Book_stock where ISBN =? ";        int stock = Jdbctemplate.queryforobject (Sql2, Integer.class, ISBN); if (stock = = 0) {throw new bookstockexception ("Insufficient stock!        ");        } String sql = "Update book_stock set stock = stock-1 where ISBN =?";    Jdbctemplate.update (sql, ISBN); } @Override public void UPDATEUSERACCOunt (string username, int price) {//verifies that the balance is sufficient, if insufficient, throws an exception String sql2 = "Select balance from account where u        Sername =? ";        int balance = Jdbctemplate.queryforobject (SQL2, Integer.class, username);        if (balance < price) {throw new useraccountexception ("Insufficient balance!"); } String sql = "Update account set balance = Balance-?"        where username =? ";    Jdbctemplate.update (SQL, price, username); }}

package com.atguigu.spring.tx;public interface BookShopService {    public void purchase(String username, String isbn);}

package com.atguigu.spring.tx;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Service("bookShopService")public class BookShopServiceImpl implements BookShopService {    @Autowired    private BookShopDao bookShopDao;    //添加事务注解    @Transactional    @Override    public void purchase(String username, String isbn) {        //1. 获取书的单价        int price = bookShopDao.findBookPriceByIsbn(isbn);        //2. 更新书的库存        bookShopDao.updateBookStock(isbn);        //3. 更新用户余额        bookShopDao.updateUserAccount(username, price);    }}

2. Test method

Package Com.atguigu.spring.tx;import Org.junit.test;import Org.springframework.context.applicationcontext;import Org.springframework.context.support.classpathxmlapplicationcontext;public class Springtransactiontest {private    ApplicationContext CTX = null;    Private Bookshopdao Bookshopdao = null;    Private Bookshopservice bookshopservice = null;        {CTX = new Classpathxmlapplicationcontext ("Applicationcontext.xml");        Bookshopdao = Ctx.getbean (Bookshopdao.class);    Bookshopservice = Ctx.getbean (Bookshopservice.class);    } @Test public void Testbookshopservice () {bookshopservice.purchase ("AA", "1001");    } @Test public void Testbookshopdaoupdateuseraccount () {Bookshopdao.updateuseraccount ("AA", 100);    } @Test public void Testbookshopdaoupdatebookstock () {Bookshopdao.updatebookstock ("1001"); } @Test public void Testbookshopdaofindpricebyisbn () {System.out.println (BOOKSHOPDAO.FINDBOOKPRICEBYISBN ("10 01 "));    }} 

3. Error throws exception

package com.atguigu.spring.tx;public class BookStockException extends RuntimeException{    /**     *      */    private static final long serialVersionUID = 1L;    public BookStockException() {        super();        // TODO Auto-generated constructor stub    }    public BookStockException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {        super(message, cause, enableSuppression, writableStackTrace);        // TODO Auto-generated constructor stub    }    public BookStockException(String message, Throwable cause) {        super(message, cause);        // TODO Auto-generated constructor stub    }    public BookStockException(String message) {        super(message);        // TODO Auto-generated constructor stub    }    public BookStockException(Throwable cause) {        super(cause);        // TODO Auto-generated constructor stub    }}

  Package Com.atguigu.spring.tx;public class Useraccountexception extends runtimeexception{/** * */    Private static final long serialversionuid = 1L;        Public Useraccountexception () {super (); TODO auto-generated Constructor stub} public useraccountexception (String message, Throwable cause, Boolean enabl Esuppression, Boolean writablestacktrace) {super (message, cause, enablesuppression, writablestacktrace)        ; TODO auto-generated Constructor stub} public useraccountexception (String message, throwable cause) {Supe        R (message, cause);        TODO auto-generated Constructor stub} public useraccountexception (String message) {super (message);        TODO auto-generated Constructor stub} public useraccountexception (Throwable cause) {super (cause); TODO auto-generated constructor stub}}  

<?xml version= "1.0" encoding= "UTF-8"? ><beans xmlns= "Http://www.springframework.org/schema/beans" xmlns:    Xsi= "Http://www.w3.org/2001/XMLSchema-instance" xmlns:context= "Http://www.springframework.org/schema/context" xmlns:tx= "Http://www.springframework.org/schema/tx" xsi:schemalocation= "http://www.springframework.org/schema/ Beans Http://www.springframework.org/schema/beans/spring-beans.xsd Http://www.springframework.org/schema/context Http://www.springframework.org/schema/context/spring-context-4.0.xsd HTTP://WWW.SPRINGFRAMEWORK.ORG/SCHEMA/TX Http://www.springframework.org/schema/tx/spring-tx-4.0.xsd "> <context:component-scan base-package=" Com.atguigu.spring "></context:component-scan> <!--import resource Files--<context:property-placeholder Locat ion= "Classpath:db.properties"/> <!--configuration c3p0 database--<bean id= "DataSource" class= "com.mchange.v2. C3p0. Combopooleddatasource "> <property name=" User "ValuE= "${jdbc.user}" ></property> <property name= "password" value= "${jdbc.password}" ></property> <property name= "Jdbcurl" value= "${jdbc.jdbcurl}" ></property> <property name= "Driverclass" value = "${jdbc.driverclass}" ></property> <property name= "initialpoolsize" value= "${jdbc.initpoolsize}" >&    lt;/property> <property name= "maxpoolsize" value= "${jdbc.maxpoolsize}" ></property> </bean> <!--configuring Spring JdbcTemplate--<bean id= "JdbcTemplate" class= "Org.springframework.jdbc.core.Jdbc Template "> <property name=" dataSource "ref=" DataSource "></property> </bean> <!--configuration transactions Manager--<bean id= "TransactionManager" class= "Org.springframework.jdbc.datasource.DataSourceTransactionMan Ager "> <property name=" dataSource "ref=" DataSource "></property> </bean> <!--enable transaction--&    Gt <tx:annotation-dRiven transaction-manager= "TransactionManager"/></beans> 

Spring Learning-DAY13