自動支持事務的類

自動支持事務的類

package aaa;

import java.util.Properties;

import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.interceptor.TransactionAttributeSourceAdvisor;
import org.springframework.transaction.interceptor.TransactionInterceptor;
import org.springframework.util.Assert;

/**
 * <p>解析JDBC事務配置</p> 
 *<meta key="tx" value="save*:PROPAGATION_REQUIRED; "/>
 *<table border="1" width="788">
  <tbody>
    <tr>
      <td width="274" align="center">隔離等級</td>
      <td width="399" align="center">描述</td>
    </tr>
    <tr>
      <td>ISOLATION_DEFAULT</td>
      <td align="center">默認隔離等級<br />
      </td>
    </tr>
    <tr>
      <td>ISOLATION_READ_UNCOMMITTED<br />
      </td>
      <td>最低隔離等級，僅僅保證了讀取過程中不會讀取到非法數據</td>
    </tr>
    <tr>
      <td>ISOLATION_READ_COMMITTED<br />
      </td>
      <td>某些數據庫的默認隔離等級；保證了一個事務不會讀到另外一個並行事務已修改但未提交的數據</td>
    </tr>
    <tr>
      <td>ISOLATION_REPEATABLE_READ<br />
      </td>
      <td>比上一個更加嚴格的隔離等級。保證了一個事務不會修改已經由另一個事務讀取但未提交（回滾）的數據</td>
    </tr>
    <tr>
      <td>ISOLATION_SERIALIZABLE</td>
      <td>性能代價最爲昂貴，最可靠的隔離等級。所有事務都嚴格隔離，可視爲各事務順序執行</td>
    </tr>
  </tbody>
</table>
<p> </p>
<p align="left">傳播途徑(Propagation Behavior)</p>
<p> </p>
<table border="1" width="791">
  <tbody>
    <tr>
      <td width="253" align="center">Propagation Behavior<br />
      </td>
      <td width="522" align="center">描述<br />
      </td>
    </tr>
    <tr>
      <td>PROPAGATION_REQUIRED </td>
      <td>支持現有事務。如果沒有則創建一個事務</td>
    </tr>
    <tr>
      <td> PROPAGATION_SUPPORTS </td>
      <td>支持現有事務。如果沒有則以非事務狀態運行。</td>
    </tr>
    <tr>
      <td> PROPAGATION_MANDATORY </td>
      <td>支持現有事務。如果沒有則拋出異常。</td>
    </tr>
    <tr>
      <td> PROPAGATION_REQUIRES_NEW </td>
      <td>總是發起一個新事務。如果當前已存在一個事務，則將其掛起。</td>
    </tr>
    <tr>
      <td>PROPAGATION_NOT_SUPPORTED </td>
      <td>不支持事務，總是以非事務狀態運行，如果當前存在一個事務，則將其掛起。</td>
    </tr>
    <tr>
      <td> PROPAGATION_NEVER </td>
      <td> 不支持事務，總是以非事務狀態運行，如果當前存在一個事務，則拋出異常。</td>
    </tr>
    <tr>
      <td> PROPAGATION_NESTED </td>
      <td>如果當前已經存在一個事務，則以嵌套事務的方式運行，如果當前沒有事務，則以默認方式(第一個)執行</td>
    </tr>
  </tbody>
</table>
 *
 */
public class TransactionManager implements BeanPostProcessor,
		BeanFactoryPostProcessor {

	private ConfigurableListableBeanFactory beanFactory;
	private DataSourceTransactionManager transactionManager;
	private static final String META_TRANSACTION_METHODS_NAME = "tx";

	public Object postProcessAfterInitialization(Object bean, String beanName)
			throws BeansException {
		if (beanFactory.containsBean(beanName)) {
			BeanDefinition beanDefinition = beanFactory
					.getBeanDefinition(beanName);

			String transactionAttributeValue = beanDefinition
					.getAttribute(META_TRANSACTION_METHODS_NAME) != null ? beanDefinition
					.getAttribute(META_TRANSACTION_METHODS_NAME).toString()
					: null;
			if (transactionAttributeValue == null) {
				return bean;
			}
			Assert.hasText(transactionAttributeValue,
					"if 'tx' meta is setted , 'tx' meta can't be empty! [ bean id:"
							+ beanName + "]");

			TransactionInterceptor transactionInterceptor = new TransactionInterceptor();
			transactionInterceptor.setTransactionManager(transactionManager);

			Properties transactionAttributes = new Properties();

			parseAttributes(transactionAttributes,transactionAttributeValue);

			transactionInterceptor
					.setTransactionAttributes(transactionAttributes);

			TransactionAttributeSourceAdvisor advisor = new TransactionAttributeSourceAdvisor(
					transactionInterceptor);

			ProxyFactory proxyFactory = new ProxyFactory();
			proxyFactory.addAdvisor(advisor);
			proxyFactory.setTarget(beanFactory.getBean(beanName));

			return proxyFactory.getProxy();
		}
		return bean;
	}

	private void parseAttributes(Properties transactionAttributes, String transactionAttributeValue) {
		String[] split = transactionAttributeValue.split(";");

		for (int i = 0; i < split.length; i++) {
			String[] splitcolon = split[i].split(":");

			if (splitcolon.length < 2) {
				break;
			}

			Assert.hasText(splitcolon[0]," can't  filled with empty string ");
			Assert.hasText(splitcolon[1]," can't  filled with empty string ");

			transactionAttributes.setProperty(splitcolon[0], splitcolon[1]);
		}
	}

	public Object postProcessBeforeInitialization(Object bean, String beanName)
			throws BeansException {
		return bean;
	}

	public void postProcessBeanFactory(
			ConfigurableListableBeanFactory beanFactory) throws BeansException {
		this.beanFactory = beanFactory;
	}

	public void setTransactionManager(
			DataSourceTransactionManager transactionManager) {
		this.transactionManager = transactionManager;
	}

}