Spring_使用XML文件的方式配置事務


步驟:

  1. 正常配置jdbctemplate
  2. 正常配置bean
  3. 配置事物管理器
  4. 配置事物管理器
  5. 配置aop切入點,通過切入點把事物鏈接起來

思路:

接着上一個買書的例子吧,直接拷到新包下,把注解都干掉,需要自動引入的直接set方法

package com.spring.bean;

public interface BookShopDao {

    //根據書號獲取書的單價
    public int findBookPriceByIsbn(String isbn);
    
    //更新數的庫存. 使書號對應的庫存 - 1
    public void updateBookStock(String isbn);
    
    //更新用戶的賬戶余額: 使 username 的 balance - price
    public void updateUserAccount(String username, int price);
}
package com.spring.bean;

import org.springframework.jdbc.core.JdbcTemplate;

public class BookShopDaoImpl implements BookShopDao {

    private JdbcTemplate jdbcTemplate;
    
    public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }
    
    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) {
        //檢查書的庫存是否足夠, 若不夠, 則拋出異常
        String sql2 = "SELECT stock FROM book_stock WHERE isbn = ?";
        int stock = jdbcTemplate.queryForObject(sql2, Integer.class, isbn);
        if(stock == 0){
            throw new BookStockException("庫存不足!");
        }
        
        String sql = "UPDATE book_stock SET stock = stock -1 WHERE isbn = ?";
        jdbcTemplate.update(sql, isbn);
    }

    @Override
    public void updateUserAccount(String username, int price) {
        //驗證余額是否足夠, 若不足, 則拋出異常
        String sql2 = "SELECT balance FROM account WHERE username = ?";
        int balance = jdbcTemplate.queryForObject(sql2, Integer.class, username);
        if(balance < price){
            throw new UserAccountException("余額不足!");
        }
        
        String sql = "UPDATE account SET balance = balance - ? WHERE username = ?";
        jdbcTemplate.update(sql, price, username);
    }

}
package com.spring.bean;

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

public class BookShopServiceImpl implements BookShopService {

    private BookShopDao bookShopDao;
    public void setBookShopDao(BookShopDao bookShopDao) {
        this.bookShopDao = bookShopDao;
    }
    @Override
    public void purchase(String username, String isbn) {
        
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {}
        
        //1. 獲取書的單價
        int price = bookShopDao.findBookPriceByIsbn(isbn);
        
        //2. 更新數的庫存
        bookShopDao.updateBookStock(isbn);
        
        //3. 更新用戶余額
        bookShopDao.updateUserAccount(username, price);
    }

}
package com.spring.bean;

import java.util.List;

public interface Cashier {

    public void checkout(String username, List<String> isbns);
    
}
package com.spring.bean;

import java.util.List;

public class CashierImpl implements Cashier {

    private BookShopService bookShopService;
    public void setBookShopService(BookShopService bookShopService) {
        this.bookShopService = bookShopService;
    }
    @Override
    public void checkout(String username, List<String> isbns) {
        for(String isbn: isbns){
            bookShopService.purchase(username, isbn);
        }
    }

}

自定義異常不貼了,和上節代碼一樣

bean配置文件

<?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"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">
    
    
    <!-- 導入資源文件 -->
    <context:property-placeholder location="classpath:db.properties"/>
    
    <!-- 配置 mysql 數據源 -->
    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="username" value="${jdbc.user}"></property>
        <property name="password" value="${jdbc.password}"></property>
        <property name="url" value="${jdbc.jdbcUrl}"></property>
        <property name="driverClassName" value="${jdbc.driverClass}"></property>
    </bean>
    
    <!-- 配置 Spirng 的 JdbcTemplate -->
    <bean id="jdbcTemplate" 
        class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    
    <!-- 配置 NamedParameterJdbcTemplate, 該對象可以使用具名參數, 其沒有無參數的構造器, 所以必須為其構造器指定參數 -->
    <bean id="namedParameterJdbcTemplate"
        class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>    
    </bean>
    <!-- 配置bean -->
    <bean id="bookShopDao" class="com.spring.bean.BookShopDaoImpl">
        <property name="jdbcTemplate" ref="jdbcTemplate"></property>
    </bean>
    <bean id="bookShopService" class="com.spring.bean.BookShopServiceImpl">
        <property name="bookShopDao" ref="bookShopDao"></property>
    </bean>
    <bean id="cashier" class="com.spring.bean.CashierImpl">
        <property name="bookShopService" ref="bookShopService"></property>
    </bean>
    <!-- 配置事務管理器 -->
    <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
    <!-- 配置事物屬性 -->
    <tx:advice id="txadvice" transaction-manager="transactionManager">
        <tx:attributes>
            <tx:method name="purchase" propagation="REQUIRES_NEW"/>
            <tx:method name="find*" read-only="true"/>
        </tx:attributes>
    </tx:advice>
    <!-- 配置事物切入點,把事物通過切入點連接起來 -->
    <aop:config>
        <aop:pointcut expression="execution(* com.spring.bean.*.*(..))" 
            id="txPointCut"/>
        <aop:advisor advice-ref="txadvice" pointcut-ref="txPointCut"/>    
    </aop:config>
<!--     <aop:config>
        <aop:pointcut expression=" execution(* com.spring.bean.* . *(..))" id="pointcut"/>
        <aop:advisor advice-ref="txadvice" pointcut-ref="pointcut"/>
    </aop:config> -->
    
</beans>

注意,

如果配置文件正確,報錯空指針異常,一般是@Autowired的實體,,沒用set方法創建實體

報錯信息如下:

org.springframework.beans.factory.xml.XmlBeanDefinitionStoreException: Line 15 in XML document from class path resource [beans.xml] is invalid; nested exception is org.xml.sax.SAXParseException; lineNumber: 15; columnNumber: 15; cvc-complex-type.2.4.c: 通配符的匹配很全面, 但無法找到元素 'aop:config' 的聲明。

一般是配置文件的頂部沒有導入相應的aop schema命名空間,把命名空間加上即可。

 


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