Programming Tutorials

By: Ashish : 2009年03月28日

Description: Are you getting javax.comm.NoSuchPortException error? If yes, then first check if ur COM port is really been detected by the driver. I'll give you one program that will display all the serial and parallel ports in your system.

By: Emiley J. : 2008年11月24日

Description: A very easy method of authenticating users with Tomcat involves creating usernames, passwords, and roles in the tomcat-users.xml file. This file is stored in /conf.

By: Emiley J. : 2008年11月24日

Description: Tomcat makes it easy to set up a connection pool so that servlets and JSPs can efficiently share database connections. In web sites that have many simultaneous users, a connection pool improves efficiency by sharing existing database connections, rather than creating a new connection and tearing it down every time an application has to use the database.

By: Ramlak : 2008年11月24日

Description: When transferring usernames and passwords over HTTP, you should set up SSL on Tomcat or whichever application server you are using. This protocol ensures that the names and passwords are in encrypted form as they travel across the network, and thus protected from theft and malicious use by hackers and other intruders.

By: MakeItSimple. : 2008年09月02日

Description: As mentioned, a report design represents a template that will be used by the JasperReports engine to deliver dynamic content to the printer, to the screen or to the Web. Data stored in the database is organized according to the report design to obtain ready to print, page oriented documents.

By: MakeItSimple. : 2008年09月02日

Description: JasperReports is a powerful open source reporting tool that has the ability to deliver rich content onto the screen, to the printer or into PDF, HTML, XLS, CSV and XML files. It is entirely written in Java and can be used in a variety of Java enabled applications to generate dynamic content.

By: MakeItSimple. : 2008年09月02日

Description: Parameters are object references that are passed-in to the report filling operations. They are very useful for passing to the report engine data that it can not normally find in its data source.

By: MakeItSimple. : 2008年09月02日

Description: Report fields represent the only way to map data from the data source into the report generating routines. When the data source of the report is a ResultSet, all fields must map to corresponding columns in the ResultSet object. That is, they must have the same name as the columns they map and a compatible type.

By: MakeItSimple. : 2008年09月02日

Description: Expressions are a powerful feature of JasperReports. They can be used for declaring report variables that perform various calculations, for data grouping on the report, to specify report text fields content or to further customize the appearance of objects on the report.

By: MakeItSimple. : 2008年09月02日

Description: A Report variable is a special objects build on top of an expression. Variables can be used to simplify the report design by declaring only once an expression that is heavily used throughout the report design or to perform various calculations on the corresponding expressions.