2.1.2 URLs in General Use

When an application uses the DriverManager to create a Connection object, it must supply a URL to the DriverManager.getConnection method. Since URLs often cause some confusion, we will first give a brief explanation of URLs in general and then go on to a discussion of JDBC URLs.
A URL (Uniform Resource Locator) gives information for locating a resource on the Internet. It can be thought of as an address.
The first part of a URL specifies the protocol used to access information, and it is always followed by a colon. Some common protocols are ftp, which specifies "file transfer protocol," and http, which specifies "hypertext transfer protocol." If the protocol is file, it indicates that the resource is in a local file system rather than on the Internet.

ftp://javasoft.com/docs/JDK-1_apidocs.zip
http://java.sun.com/products/JDK/CurrentRelease
file:/home/haroldw/docs/tutorial.html

The rest of a URL, everything after the first colon, gives information about where the data source is located. If the protocol is file, the rest of the URL is the path for the file. For the protocols ftp and http, the rest of the URL identifies the host and may optionally give a path to a more specific site. For example, here is the URL for the Java Software home page. This URL identifies only the host: