商户系统和微信支付系统主要交互：

商户后台收到来自微信开放平台的支付成功回调通知，标志该笔订单支付成功。

The CascadeType.REMOVE is automatically inherited when using CascadeType.ALL, but the entity removal is not only applied to the link table, but to the other side of the association as well.

MERGE

The Post entity plays the Parent role and the PostDetails is the Child.

PostDetails

you may want to add a mappedBy="addressOwner" attribute to your User to signal to the persistence provider that the join column should be in the ADDRESS table.

used to interact with the persistence context.

3个标准Annotation类型

在Java中元数据以标签的形式存在于Java代码中，元数据标签的存在并不影响程序代码的编译和执行，它只是被用来生成其它的文件或针在运行时知道被运行代码的描述信息。

Internal Repositories

plugins can contain information that indicates which lifecycle phase to bind a goal to.

Installing a JDBC driver

the DataSource object that is implemented to interact with xads and other XADataSource objects is deployed.

has deployed a ConnectionPoolDataSource object and a DataSource object properly

bought its DataSource class, com.applogic.PooledDataSource, from its EJB server vendor, Application Logic, Inc.

bought a JDBC driver from DB Access, Inc. that includes the class com.dbaccess.ConnectionPoolDS, which implements the ConnectionPoolDataSource interface.

com.dbaccess.ConnectionPoolDS cpds = new com.dbaccess.ConnectionPoolDS(); cpds.setServerName("creamer"); cpds.setDatabaseName("COFFEEBREAK"); cpds.setPortNumber(9040); cpds.setDescription("Connection pooling for " + "COFFEEBREAK DBMS");

After the ConnectionPoolDataSource object has been registered with a JNDI naming service, the DataSource object is deployed.

Deploying

Context ctx = new InitialContext(); DataSource ds = (DataSource)ctx.lookup("jdbc/billingDB");

the method returns the DataSource object that the system administrator bound to jdbc/billingDB at deployment time.

First, the system administrator creates the BasicDataSource object ds using the default constructor.

A DataSource object represents a particular DBMS or some other data source, such as a file.

When we are working with Spring MVC and are also using Spring in the services layer, we provide two application-contexts. The first one is configured using ContextLoaderListener and the other with DispatcherServlet.

// An ApplicationContext is just a BeanFactory

Like generic application contexts, web application contexts are hierarchical. There is a single root context per application, while each servlet in the application (including a dispatcher servlet in the MVC framework) has its own child context.