Programmer Group

Preface There is a requirement in the project to export the contract content to pdf. IText is an open source Java library for generating PDF documents. It can dynamically generate PDF from XML or database. It can also encrypt documents, control privileges, and support Java/C# etc. But the HTML parser provided by iText itself is not strong enoug ...

Asynchronous servlet is introduced in Servlet 3. This is a good way to deal with thread starvation when running threads for long periods of time. Async Servlet Before we understand what an asynchronous Servlet is, let's try to understand why we need it. Suppose we have a Servlet that takes a lot of time, like the fol ...

Log4net introduction Log4net, Apache's next open source project, is a clone of Log4j. We can control the destination of log information output. Log4net defines a variety of log information output modes. It can output logs to console, text files, windows log event viewer, including database, mail and other locations, so that we can quickly trac ...

1.Validate 1.1 Rewriting validate Method For example, do the login page on the front desk action: 1.2 checkout framework 1. Write a checking rule file It is a typical XML file in the format of ActionName-validation.xml The validation file needs to add a dtd constraint description The dtd description is in xwork-core <!DOCTYPE va ...

Persistent Ephemeral Node / Persistent Node A persistent node that can be maintained when a link or session is interrupted. 1. key API org.apache.curator.framework.recipes.nodes.PersistentEphemeralNode 2. mechanism description Actually, it's org.apache.curator.framework.recipes.nodes.PersistentNode. Considering a lot of abnormal situations, it ...