Spring之TransactionTemplate

「爱情、让人受尽委屈。」 2022-03-16 08:10 149阅读 0赞

## Spring 官方文档 ##

*  [Spring Framework Documentation【Version 5.1.4.RELEASE】][Spring Framework Documentation_Version 5.1.4.RELEASE]
 *  [TransactionTemplate API Doc][]

## 介绍 ##

*  Spring可以支持编程式事务和声明式事务。
 *  Spring提供的最原始的事务管理方式是基于TransactionDefinition、PlatformTransactionManager、TransactionStatus 编程式事务。
 *  而TransactionTemplate的编程式事务管理是使用模板方法设计模式对原始事务管理方式的封装。

## 源码 ##

@SuppressWarnings("serial")
    public class TransactionTemplate extends DefaultTransactionDefinition
    		implements TransactionOperations, InitializingBean { 
    
    	/** Logger available to subclasses */
    	protected final Log logger = LogFactory.getLog(getClass());
    
    	private PlatformTransactionManager transactionManager;
    
    	public TransactionTemplate() { 
    	}
    
    	/** * Construct a new TransactionTemplate using the given transaction manager. * @param transactionManager the transaction management strategy to be used */
    	public TransactionTemplate(PlatformTransactionManager transactionManager) { 
    		this.transactionManager = transactionManager;
    	}
    
    	/** * Construct a new TransactionTemplate using the given transaction manager, * taking its default settings from the given transaction definition. * @param transactionManager the transaction management strategy to be used * @param transactionDefinition the transaction definition to copy the * default settings from. Local properties can still be set to change values. */
    	public TransactionTemplate(PlatformTransactionManager transactionManager, TransactionDefinition transactionDefinition) { 
    		super(transactionDefinition);
    		this.transactionManager = transactionManager;
    	}
    
    
    	/** * Set the transaction management strategy to be used. */
    	public void setTransactionManager(PlatformTransactionManager transactionManager) { 
    		this.transactionManager = transactionManager;
    	}
    
    	/** * Return the transaction management strategy to be used. */
    	public PlatformTransactionManager getTransactionManager() { 
    		return this.transactionManager;
    	}
    
    	@Override
    	public void afterPropertiesSet() { 
    		if (this.transactionManager == null) { 
    			throw new IllegalArgumentException("Property 'transactionManager' is required");
    		}
    	}
    
    
    	@Override
    	public <T> T execute(TransactionCallback<T> action) throws TransactionException { 
    		if (this.transactionManager instanceof CallbackPreferringPlatformTransactionManager) { 
    			return ((CallbackPreferringPlatformTransactionManager) this.transactionManager).execute(this, action);
    		}
    		else { 
    			TransactionStatus status = this.transactionManager.getTransaction(this);
    			T result;
    			try { 
    				result = action.doInTransaction(status);
    			}
    			catch (RuntimeException ex) { 
    				// Transactional code threw application exception -> rollback
    				rollbackOnException(status, ex);
    				throw ex;
    			}
    			catch (Error err) { 
    				// Transactional code threw error -> rollback
    				rollbackOnException(status, err);
    				throw err;
    			}
    			catch (Throwable ex) { 
    				// Transactional code threw unexpected exception -> rollback
    				rollbackOnException(status, ex);
    				throw new UndeclaredThrowableException(ex, "TransactionCallback threw undeclared checked exception");
    			}
    			this.transactionManager.commit(status);
    			return result;
    		}
    	}
    
    	/** * Perform a rollback, handling rollback exceptions properly. * @param status object representing the transaction * @param ex the thrown application exception or error * @throws TransactionException in case of a rollback error */
    	private void rollbackOnException(TransactionStatus status, Throwable ex) throws TransactionException { 
    		logger.debug("Initiating transaction rollback on application exception", ex);
    		try { 
    			this.transactionManager.rollback(status);
    		}
    		catch (TransactionSystemException ex2) { 
    			logger.error("Application exception overridden by rollback exception", ex);
    			ex2.initApplicationException(ex);
    			throw ex2;
    		}
    		catch (RuntimeException ex2) { 
    			logger.error("Application exception overridden by rollback exception", ex);
    			throw ex2;
    		}
    		catch (Error err) { 
    			logger.error("Application exception overridden by rollback error", ex);
    			throw err;
    		}
    	}
    
    }

--------------------

相关文档：  
1.[https://blog.csdn.net/qq\_33404395/article/details/83377382][https_blog.csdn.net_qq_33404395_article_details_83377382]

[Spring Framework Documentation_Version 5.1.4.RELEASE]: https://docs.spring.io/spring/docs/5.1.4.RELEASE/spring-framework-reference
[TransactionTemplate API Doc]: https://docs.spring.io/spring-framework/docs/5.1.4.RELEASE/javadoc-api/org/springframework/transaction/support/TransactionTemplate.html
[https_blog.csdn.net_qq_33404395_article_details_83377382]: https://blog.csdn.net/qq_33404395/article/details/83377382