关于JDBC

脑补一下JDBC基础知识，原文链接：http://docs.oracle.com/javase/tutorial/jdbc/basics/gettingstarted.html

If you are using Java DB, it already comes with a JDBC driver. If you are using MySQL, install the latest version of Connector/J.
 
Contact the vendor of your database to obtain a JDBC driver for your DBMS.
 
There are many possible implementations of JDBC drivers. These implementations are categorized as follows:
 
Type : Drivers that implement the JDBC API as a mapping to another data access API, such as ODBC (Open Database Connectivity). Drivers of this type are generally dependent on a native library, which limits their portability. The JDBC-ODBC Bridge is an example of a Type  driver.
 
Note: The JDBC-ODBC Bridge should be considered a transitional solution. It is not supported by Oracle. Consider using this only if your DBMS does not offer a Java-only JDBC driver.
 
Type : Drivers that are written partly in the Java programming language and partly in native code. These drivers use a native client library specific to the data source to which they connect. Again, because of the native code, their portability is limited. Oracle's OCI (Oracle Call Interface) client-side driver is an example of a Type 2 driver.
 
Type : Drivers that use a pure Java client and communicate with a middleware server using a database-independent protocol. The middleware server then communicates the client's requests to the data source.
 
Type : Drivers that are pure Java and implement the network protocol for a specific data source. The client connects directly to the data source.
 
Check which driver types comes with your DBMS. Java DB comes with two Type 4 drivers, an Embedded driver and a Network Client Driver. MySQL Connector/J is a Type 4 driver.
 
Installing a JDBC driver generally consists of copying the driver to your computer, then adding the location of it to your class path. In addition, many JDBC drivers other than Type  drivers require you to install a client-side API. No other special configuration is usually needed.

PS：天天群里吵吵什么JDBC多少种类型，这里给脑补一下，谁看到就好好看看那。另外原文中有标红的部分请注意一下。