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Created by Fang on August 23, 2010 22:55:58    Last update: August 24, 2010 15:45:04
The tags XML flow control tags are exactly the same as their Core flow control equivalents, except that the test condition with a boolean EL expression is replaced by the select condition with an XPath expression. In the case of the forEach tag, the items attribute is replaced with the select attribute. In a test condition, the XPath expression is evaluated to a boolean value by the rules of the XPath boolean() function, which converts its argument to a boolean as follows: a number is true if and only if it is neither positive or negative zero nor NaN. a node-set is true if and only if it is non-empty. a string is true if and only if its length is non-zero. an object of...
Created by Fang on July 26, 2010 19:18:28    Last update: August 18, 2010 19:13:02
The tags <c:import> The <c:import> tag imports the contents of a URL and expose that in one of three ways: Import contents from a URL and write it out to the page (url may be relative or absolute): <c:import url="theUrl" /> Import contents from a URL and save it to a scoped variable string named by the var attribute. Use the scope attribute to define the scope of the exported variable. <c:import url="theUrl" var="importTest" scope="ses... Import a URL and expose to a Reader object named by the varReader attribute. The scope attribute does not apply. The varReader scoped variable can only be accessed within the body of <c:import> . <c:import url="theUrl" varReader="theReader"/> <c:url> The <c:url> tag constructs a URL and writes it out to the...
Created by Fang on August 17, 2010 21:08:13    Last update: August 17, 2010 21:08:13
JSTL string manipulation functions String manipulation functions are simple and self-evident. You just need to know that they exist. Test it Make these additions to the expanded test application : Create a new Java class StringManipulation : package jstl.demo.handler; import java.... Create a new JSP ( stringmanipulation.jsp ) under webapp : <%@ taglib uri="http://java.sun.com/jsp/jstl/c... Compile and package the WAR with: mvn package Deploy the WAR to a servlet container of your choice (for example, Tomcat or JBoss). Test the page with this URL (Tomcat/JBoss running on port 8080): http://localhost:8080/jstl-demo/demo/StringManipulation You may adjust the URL if your servlet container runs on a different port or the web app is bound to a different context root.
Created by Fang on August 17, 2010 19:27:32    Last update: August 17, 2010 19:27:32
Get the length of a collection The length function returns the size of a collection. It can be applied to any object supported by the JSTL core tag <c:forEach> , namely: Arrays Implementation of java.util.Collection Implementation of java.util.Iterator Implementation of java.util.Enumeration Implementation of java.util.Map String When used on String , it returns the number of characters in the string. Test it Make these additions to the expanded test application : Create a new Java class LengthFunction : package jstl.demo.handler; import java.... Create a new JSP ( lengthfunction.jsp ) under webapp : <%@ taglib uri="http://java.sun.com/jsp/jstl/c... Compile and package the WAR with: mvn package Deploy the WAR to a servlet container of your choice (for example, Tomcat or JBoss). Test the page with this URL...
Created by Fang on August 16, 2010 22:00:05    Last update: August 16, 2010 22:12:25
The tags <sql:update> Executes SQL INSERT , UPDATE , DELETE statements, or SQL DDL statements. Syntax: <sql:update sql="sqlUpdate" [dataSource="d... or, put the SQL within the element body: <sql:update [dataSource="dataSource"] [v... Attributes: Name Dynamic? Type Description sql true String SQL update statement. dataSource true javax.sql.DataSource or String Data source associated with the database to update. A String value represents a relative path to a JNDI resource or the parameters for the JDBC DriverManager class. var false String Name of the exported scoped variable for the result of the database update. The type of the scoped variable is java.lang.Integer . scope false String Scope of var. Defaults to "page". <sql:transaction> Establishes a transaction context for <sql:query> and <sql:update> subtags. Syntax: <sql:transaction [dataSource="dataSource"] ... where...
Created by Fang on August 16, 2010 21:44:41    Last update: August 16, 2010 22:01:46
The tags <sql:query> Queries a database. Syntax: <sql:query sql="sqlQuery" var="varName" [scope... or, put the query within the element body: <sql:query var="varName" [scope="{page|req... Attributes: Name Dynamic? Type Description sql true String SQL query statement. dataSource true javax.sql.DataSource or String Data source associated with the database to query. A String value represents a relative path to a JNDI resource or the JDBC parameters for the DriverManager class. maxRows true int The maximum number of rows to be included in the query result. If not specified, or set to -1, no limit on the maximum number of rows is enforced. startRow true int The returned Result object includes the rows starting at the specified index. The first row of the original query result set is at index...
Created by Fang on April 04, 2010 04:12:14    Last update: July 21, 2010 14:52:58
The tags <c:if> The <c:if> tag may be used with or without body content: <!-- Without body content, used to export vari... In my opinion, the version without body content is pretty much useless (the <c:set> tag is a lot more meaningful for this purpose). If body content exists, it is inserted into the page if the testCondition is true . Optional attributes var and scope may be specified. If var is specified, a variable whose name is the value of var is exported to the associated scope ( pageScope if no scope is specified). The type of the exported variable is Boolean and its value is the value of the testCondition . <c:choose>, <c:when>, <c:otherwise> These tags imitate the Java control structure if...else...