Lesson 11 Scripts Hello. One of the things THAT I’ve realized in the last couple of years is that there’s a great feature in Java that a lot of people don’t notice, but you need to build larger systems or more scalable systems, and that’s script technology.
Before you learn the technology, look at the scene.
In the application systems we do, we often need to set up some business rules. For example, whether it is the firewall at the network layer or the data permission at the application layer, common users want to set a rule for network permission, such as IP between 192.168.2.101 and 192.168.2.149. Port =80 or port=8080 or port=21, level>3 and department in (‘ ‘IT,’ ADMIN ‘), etc. Don’t want to write some calculation method, and die in the code, but pulled allow users to configure, such as insurance premiums, is likely to be based on a pile of conditions and the formula calculated, crucially each year may have changes, natural can modify the source code, but if the formula designed to configuration, system is more flexible and extensible.
One of the most frustrating aspects of being an application programmer is the constant, sometimes overwhelming, daily change in requirements. Domestic enterprise is used to make the system into a package, no matter how much labor is paid the price of this package, the user adds content ceaselessly, modify ceaselessly, feel today is but yesterday is not, and the sales department feels not to be such a bit of change, still wrong person a bit better? So programmers had to keep revising, tired, not good. One of my former company leaders once joked to me, “You programmers grind your teeth day in and day out and don’t produce anything. What are you all doing?”
From that point on, I wondered if I could externalize all these permission rules, calculation formulas, flows, and so on into configuration files and let users define Y themselves