When i run the following simple code in eclipse with App. Server Information : Apache Tomcat/7.0.26 , Sevlet Version : 3.0 , JSP Version : 2.1 and Java Version : 1.6.0_20
<c:forEach var="i" begin="1" end="50" step="1" >
<c:out value="${i}"/ >
</c:forEach >
I got the error "According to TLD or attribute directive in tag file, attribute value does not accept any expressions" . If you get the same error , making the below changes in the JSP will save your day.
Replace the line <%@ taglib uri='http://java.sun.com/jstl/core' prefix='c'% > in the JSP with either
<%@ taglib uri='http://java.sun.com/jsp/jstl/core' prefix='c'% > OR
<%@ taglib uri='http://java.sun.com/jstl/core_rt' prefix='c'% >
Let us see how the problem is solved .
Tag library descriptor (TLD) files play major role because it maps the tag and the tag handler class . You need to just include taglib directive in the JSP with absolute URI mentioned in the tld file sothat the page can use
the tags defined in a tag library. TLD file has various attributes to be passed to the tag handler class. One of the attribute is value which accepts value or the expression to be evaluated depending upon the node
rtexprvalue (run time expression value) value as given below <rtexprvalue >true </rtexprvalue > . If it is true , it accepts , the expression , otherwise not. Now let us see the reason.
Suppose you are using jstl-1.2.jar and standard-1.1.2.jar , it has three .tld files for each library
For example , core library has three tld files (c-1_0.tld , c-1_0-rt.tld , c.tld ) , format library has three tld files that are fmt-1_0.tld , fmt-1_0-rt.tld , fmt.tld . Similary xml , sql
library have three tld files each , functions library has only one tld file. You can see the tld files in the META-INF folder when you extract the jar files.
Now let us take the core library tld files c-1_0.tld , c-1_0-rt.tld , c.tld . Each tld files have some changes . I have noticed some of the changes . Please gothrough the tld files given below which are related to
our problem
According to the old c-1_0.tld , some of the specifications are as follows
1. attribute value does not accept any runtime expressions(rt) , 2. it uses DTD to define the struture of XML document , 3 .it uses the encoding format "ISO-8859-1" , 4. URI to identify the tag library
descriptor (TLD) file uniquely is http://java.sun.com/jstl/core , 5. JSTL version 1.0 , 6. required JSP version is 1.2
Part of the tld file is given below
<?xml version="1.0" encoding="ISO-8859-1" ? >
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd" >
<taglib >
.........
.........
<jsp-version >1.2 </jsp-version >
<short-name >c </short-name >
<uri >http://java.sun.com/jstl/core </uri >
<description >JSTL 1.0 core library </description >
<attribute >
<name >value </name >
<required >false </required >
<rtexprvalue >false </rtexprvalue > // false - does not accept rt expression
</attribute >
....................
According to the c-1_0-rt.tld file ,
1. attribute value accepts runtime expressions(rt) , 2. URI to identify the tag library descriptor (TLD) file is http://java.sun.com/jstl/core_rt , 3. JSTL version 1.0 , 4. required JSP version is 1.2
Part of the tld file is given below
<?xml version="1.0" encoding="ISO-8859-1" ? >
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd" >
....
......
<jsp-version >1.2 </jsp-version >
<short-name >c_rt </short-name >
<uri >http://java.sun.com/jstl/core_rt </uri >
<display-name >JSTL core RT </display-name >
<description >JSTL 1.0 core library </description >
<attribute >
<name >value </name >
<required >false </required >
<rtexprvalue >true </rtexprvalue > // true - accepts rt expression
</attribute >
......................
According to the latest c.tld file ,
1. attribute value accepts any runtime expressions(rt) , 2. it uses XSD (XML Schema) to define the struture of XML document , 3. it uses the encoding format "UTF-8" , 4. URI to identify the
tag library descriptor (TLD) file is http://java.sun.com/jsp/jstl/core , 5. data type is fixed for most of the variables which ensures the type safe , 5. JSTL version 1.1 , 6. required JSP version is 2.0
Part of the tld file is given below
<?xml version="1.0" encoding="UTF-8" ? >
<taglib xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" version="2.1" >
.....
.....
<description >JSTL 1.1 core library </description >
<short-name >c </short-name >
<uri >http://java.sun.com/jsp/jstl/core </uri >
.....
<attribute >
<description >
Expression to be evaluated.
</description >
<name >value </name >
<required >false </required >
<rtexprvalue >true </rtexprvalue >
<deferred-value >
<type >java.lang.Object </type >
</deferred-value >
</attribute >
...............
Now you have to decide which URI you have to use with taglib directive .
Summary to remember
JSTL 1.0 is compatible with : Servlet 2.3 , JSP 1.2 , suitable URI is http://java.sun.com/jstl/core . To accept RT expression , use http://java.sun.com/jstl/core_rt
JSTL 1.1 is compatible with Servlet 2.4 , JSP 2.0 , suitable URI is http://java.sun.com/jsp/jstl/core . To work with old .tld file , use the URI http://java.sun.com/jstl/core_rt
JSTL 1.2 is compatible with Servlet 2.5 onwards , JSP 2.1 , suitable URI is http://java.sun.com/jsp/jstl/core .Still you have chance to work with old .tld file using the URI http://java.sun.com/jstl/core_rt
<c:forEach var="i" begin="1" end="50" step="1" >
<c:out value="${i}"/ >
</c:forEach >
I got the error "According to TLD or attribute directive in tag file, attribute value does not accept any expressions" . If you get the same error , making the below changes in the JSP will save your day.
Replace the line <%@ taglib uri='http://java.sun.com/jstl/core' prefix='c'% > in the JSP with either
<%@ taglib uri='http://java.sun.com/jsp/jstl/core' prefix='c'% > OR
<%@ taglib uri='http://java.sun.com/jstl/core_rt' prefix='c'% >
Let us see how the problem is solved .
Tag library descriptor (TLD) files play major role because it maps the tag and the tag handler class . You need to just include taglib directive in the JSP with absolute URI mentioned in the tld file sothat the page can use
the tags defined in a tag library. TLD file has various attributes to be passed to the tag handler class. One of the attribute is value which accepts value or the expression to be evaluated depending upon the node
rtexprvalue (run time expression value) value as given below <rtexprvalue >true </rtexprvalue > . If it is true , it accepts , the expression , otherwise not. Now let us see the reason.
Suppose you are using jstl-1.2.jar and standard-1.1.2.jar , it has three .tld files for each library
For example , core library has three tld files (c-1_0.tld , c-1_0-rt.tld , c.tld ) , format library has three tld files that are fmt-1_0.tld , fmt-1_0-rt.tld , fmt.tld . Similary xml , sql
library have three tld files each , functions library has only one tld file. You can see the tld files in the META-INF folder when you extract the jar files.
Now let us take the core library tld files c-1_0.tld , c-1_0-rt.tld , c.tld . Each tld files have some changes . I have noticed some of the changes . Please gothrough the tld files given below which are related to
our problem
According to the old c-1_0.tld , some of the specifications are as follows
1. attribute value does not accept any runtime expressions(rt) , 2. it uses DTD to define the struture of XML document , 3 .it uses the encoding format "ISO-8859-1" , 4. URI to identify the tag library
descriptor (TLD) file uniquely is http://java.sun.com/jstl/core , 5. JSTL version 1.0 , 6. required JSP version is 1.2
Part of the tld file is given below
<?xml version="1.0" encoding="ISO-8859-1" ? >
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd" >
<taglib >
.........
.........
<jsp-version >1.2 </jsp-version >
<short-name >c </short-name >
<uri >http://java.sun.com/jstl/core </uri >
<description >JSTL 1.0 core library </description >
<attribute >
<name >value </name >
<required >false </required >
<rtexprvalue >false </rtexprvalue > // false - does not accept rt expression
</attribute >
....................
According to the c-1_0-rt.tld file ,
1. attribute value accepts runtime expressions(rt) , 2. URI to identify the tag library descriptor (TLD) file is http://java.sun.com/jstl/core_rt , 3. JSTL version 1.0 , 4. required JSP version is 1.2
Part of the tld file is given below
<?xml version="1.0" encoding="ISO-8859-1" ? >
<!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN" "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd" >
....
......
<jsp-version >1.2 </jsp-version >
<short-name >c_rt </short-name >
<uri >http://java.sun.com/jstl/core_rt </uri >
<display-name >JSTL core RT </display-name >
<description >JSTL 1.0 core library </description >
<attribute >
<name >value </name >
<required >false </required >
<rtexprvalue >true </rtexprvalue > // true - accepts rt expression
</attribute >
......................
According to the latest c.tld file ,
1. attribute value accepts any runtime expressions(rt) , 2. it uses XSD (XML Schema) to define the struture of XML document , 3. it uses the encoding format "UTF-8" , 4. URI to identify the
tag library descriptor (TLD) file is http://java.sun.com/jsp/jstl/core , 5. data type is fixed for most of the variables which ensures the type safe , 5. JSTL version 1.1 , 6. required JSP version is 2.0
Part of the tld file is given below
<?xml version="1.0" encoding="UTF-8" ? >
<taglib xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd" version="2.1" >
.....
.....
<description >JSTL 1.1 core library </description >
<short-name >c </short-name >
<uri >http://java.sun.com/jsp/jstl/core </uri >
.....
<attribute >
<description >
Expression to be evaluated.
</description >
<name >value </name >
<required >false </required >
<rtexprvalue >true </rtexprvalue >
<deferred-value >
<type >java.lang.Object </type >
</deferred-value >
</attribute >
...............
Now you have to decide which URI you have to use with taglib directive .
Summary to remember
JSTL 1.0 is compatible with : Servlet 2.3 , JSP 1.2 , suitable URI is http://java.sun.com/jstl/core . To accept RT expression , use http://java.sun.com/jstl/core_rt
JSTL 1.1 is compatible with Servlet 2.4 , JSP 2.0 , suitable URI is http://java.sun.com/jsp/jstl/core . To work with old .tld file , use the URI http://java.sun.com/jstl/core_rt
JSTL 1.2 is compatible with Servlet 2.5 onwards , JSP 2.1 , suitable URI is http://java.sun.com/jsp/jstl/core .Still you have chance to work with old .tld file using the URI http://java.sun.com/jstl/core_rt
