Jakarta Standard Tag Library API Best Practices Guide

Jakarta Standard Tag Library (JSTL) is a label library commonly used in the development of the Java Web application.This article will provide developers with the best practical guide to JSTL API, which aims to help them write high -efficiency and maintainable code when using JSTL. Jstl API Best Practice Guide JSTL is designed to simplify logic logic using Java code on the JSP page.It provides a set of labels and functions to handle various common tasks, such as iteration, conditional judgment, formatting output and internationalization.Here are the best practices when using JSTL API. 1. Import jstl library Before using JSTL, you need to import the JSTL library in the project.You can download the jstl library from the official website (https://jstl.java.net/) and add relevant jar files to the project path. 2. Select the right tag JSTL provides multiple label libraries, each label library is used for different tasks.The correct selection of the label library can improve the readability and performance of the code.For example, using the Core tag library to process basic logic and control flows, the FMT label library is used to formatting and localization, and the SQL tag library is used to perform database operations. 3. Avoid using JSTL expressions in the cycle When using JSTL expressions, try to avoid repeatedly calculating the expression value in the cycle.This will lead to unnecessary performance expenses.The calculation results can be saved into the variable, and these variables are reused in the cycle. Example code: <c:set var="total" value="${0}" /> <c:forEach items="${items}" var="item"> <c:set var="total" value="${total + item}" /> </c:forEach> Total: ${total} In the above example, we use the <C: Set> tag to initialize the variable to 0 to 0, and use the <C: Set> tag to update the value of Total in the cycle.In this way, we can avoid re -calculating the value of Total at each cycle. 4. Use EL expression to replace script language JSTL provides expression language (EL) to handle dynamic content.We should use EL expressions as much as possible instead of using script language, such as Java scripts or script elements.EL expression is more readable and easier to maintain. Example code: <c:forEach items="${users}" var="user"> <c:out value="${user.name}" /> </c:forEach> In the above example, we use EL expression `$ {user.name}` to get the name of the user object and use the <C: OUT> tag output. 5. Packing the logic code into a custom tag When you need to reuse certain logic code frequently, you can encapsulate it as a custom label.Custom labels gather related logic to make the code more maintainable and reused. Example code: <my:formatDate value="${date}" pattern="yyyy-MM-dd" /> In the above example, we use a custom tag `<my: formatdate>` to format the date.The custom label contains the format logic code, which separates it from other code to improve the readability and maintenance of the code. in conclusion By following these best practices, developers can better use the JSTL API and write high -efficiency and maintainable code.Proficient in using the JSTL API can accelerate the development process and improve the performance and readability of the application.I hope this article can help developers using JSTL. I hope these examples can help you.If you have any questions when using JSTL, please ask us at any time.