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Created by Fang on March 30, 2012 10:07:25    Last update: March 30, 2012 10:09:08
After a user resets a password, I want to force the user to change the password before she gets access to secured content. This is usually done with a servlet filter. But with Spring MVC, you can also use a HandlerInterceptor . According to Spring JavaDoc: HandlerInterceptor is basically similar to a Servlet 2.3 Filter, but in contrast to the latter it just allows custom pre-processing with the option of prohibiting the execution of the handler itself, and custom post-processing. Filters are more powerful, for example they allow for exchanging the request and response objects that are handed down the chain. Note that a filter gets configured in web.xml, a HandlerInterceptor in the application context. As a basic guideline, fine-grained handler-related preprocessing tasks are candidates...
Created by Fang on November 21, 2011 15:57:49    Last update: November 22, 2011 09:51:26
The improved custom taglib works with existing facelet ui taglibs. For example: <ui:param name="theName" value="John"/> <my:hel... produces the expected output. However, a problem exists with the ui:repeat tag: <h3>With ui:repeat</h3> <ui:repeat var="theName... When tested with a URL like: http://localhost:8080/facelet-demo/?name=Zack&name... the raw EL prints out the correct names, but my custom tag substitutes empty string for theName2 ! In theory, the response is rendered in the Render Response phase, way after the Apply Request Values phase, actual values should be available to EL. The answer to this anomaly turned out to be very deep ! Yes, right there in the code! I would consider this a bug in facelets implementation, but the JSF spec did not tell what the expected behavior should be. In my custom...
Created by Fang on November 10, 2011 09:26:12    Last update: November 10, 2011 09:26:12
Syntax highlighted XML schema for JSF 2.0 Application Configuration Resource File ( faces-config.xml ). Almost 3000 lines! <?xml version="1.0" encoding="UTF-8"?> <xsd:sch...
Created by Dr. Xi on July 14, 2011 09:28:57    Last update: July 14, 2011 09:28:57
Java arrays are fixed size, so you have to make a new array with smaller size and copy the data. For JDK6 and above: // import java.util.Arrays; newArray = Arrays.c... Before that (using Object as example): Object[] newArray = new Object [newSize] ; Syst...
Created by Fang on August 24, 2010 18:44:24    Last update: August 24, 2010 18:44:24
The tags XML transform tags apply XSLT to XML documents. The XML document may be specified as the doc attribute or enclosed as the body of the <x:transform> tag. Optional <x:param> tags may be used to specify parameters for the XSLT. <x:transform> Syntax: <x:transform doc="XMLDocument" xslt="XSLTStyle... or, include the XML document in the body: <x:transform xslt="XSLTStylesheet" [docSystem... Attributes: Name Dynamic? Type Description doc true String , Reader , javax.xml.transform.Source , org.w3c.dom.Document , or object exported by <x:parse> , <x:set> . Source XML document to be transformed. (If exported by <x:set> , it must correspond to a well-formed XML document, not a partial document.) xslt true String , Reader or javax.xml.transform.Source Transformation stylesheet as a String , Reader , or Source object. docSystemId true...
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 August 19, 2010 18:32:28    Last update: August 19, 2010 18:32:28
The tags <x:parse> Parses an XML document. The document to be parsed can be specified by the doc attribute or enclosed as the body of the tag. The parsed document is exposed as the var attribute or the varDom attribute. When exposed as var , the type of the exposed object is implementation dependent; when exposed as varDom , the type of the exposed object is org.w3c.dom.Document . Objects exposed by var and varDom can both be used to set the context of an XPath expression. Syntax: <x:parse doc="XMLDocument" {var="var" [sco... or, put the XML document in the element body: <x:parse {var="var" [scope="page|request|s... Attributes: Name Dynamic? Type Description doc true String , Reader Source XML document to be parsed. systemId true String The...
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 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 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...
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