Unless you're doing this purely for educational purposes, I'd recommend dropping
the custom tag approach. Just have your "tmsBean" expose the results of the
database query as a collection (does the getRecords method already do that?)
and use <c:forEach> to iterate through it and render the <option> elements.
Quoting Sven Lösekann <[EMAIL PROTECTED]>:
> Hello,
>
> I am trying to develop my own tags. I do not know if this is the right place
> to ask but I hope so. The Tag I am developing should read string from a db
> and put it in a <select> box on the page. I just can not get it to work and
> I am running out of ideas. Please tell me what I am doing wrong. I really
> need this code to run. Here comes my code:
>
> package tags;
>
> import javax.servlet.jsp.*;
>
> import javax.servlet.jsp.tagext.*;
>
> import dataconn.*;
>
> /**
>
> * @author Loesekann
>
> *
>
> * To change the template for this generated type comment go to
>
> * Window>Preferences>Java>Code Generation>Code and Comments
>
> */
>
> public class DBCombobox extends TagSupport {
>
> private String colum = null;
>
> private String table = null;
>
> private String name = null;
>
> private String css_class = null;
>
> private String def_str = null;
>
> public DBCombobox() {
>
> super();
>
> }
>
> /**
>
> * doStartTag is called by the JSP container when the tag is encountered
>
> */
>
> public int doStartTag() {
>
> try {
>
> System.out.println("Tag Start\n");
>
> JspWriter page = pageContext.getOut();
>
> page.println("<select size=\"1\" name=" +name+ " class=" +css_class+ ">");
>
> page.println("<option value=''></option>");
>
> tmsDataBean tmsBean = (tmsDataBean)pageContext.findAttribute("tmsBean");
>
> tmsBean.setQuery("select distinct " +colum+ " from " +table);
>
> if(tmsBean.getRecords()){
>
> String Value = null;
>
> while(tmsBean.getNextRecord()){
>
> Value=tmsBean.getColumn(colum);
>
> page.print("<option value='" +Value+"' ");
>
> if(def_str.equals(Value))
>
> page.print(" selected ");
>
> page.print(">" +Value+ "</option>");
>
> }
>
> tmsBean.cleanup();
>
> }
>
> }catch(Exception e) {
>
> System.out.println("doStartTag Exception.\n");
>
> e.printStackTrace();
>
> }
>
> //Must return SKIP_BODY because we are not supporting a body for this
>
> // tag.
>
> return SKIP_BODY;
>
> }
>
>
> /**
>
> * doEndTag is called by the JSP container when the tag is closed
>
> */
>
> public int doEndTag(){
>
> try {
>
> JspWriter out = pageContext.getOut();
>
> out.println("</select>");
>
> } catch (Exception e){
>
> System.out.println("doEndTag Exception");
>
> e.printStackTrace();
>
> }
>
> return EVAL_PAGE;
>
> }
>
> /**
>
> * @return
>
> */
>
> public String getColum() {
>
> return colum;
>
> }
>
> /**
>
> * @return
>
> */
>
> public String getCss_class() {
>
> return css_class;
>
> }
>
> /**
>
> * @return
>
> */
>
> public String getDef_str() {
>
> return def_str;
>
> }
>
> /**
>
> * @return
>
> */
>
> public String getName() {
>
> return name;
>
> }
>
> /**
>
> * @return
>
> */
>
> public String getTable() {
>
> return table;
>
> }
>
> /**
>
> * @param string
>
> */
>
> public void setColum(String string) {
>
> colum = string;
>
> }
>
> /**
>
> * @param string
>
> */
>
> public void setCss_class(String string) {
>
> css_class = string;
>
> }
>
> /**
>
> * @param string
>
> */
>
> public void setDef_str(String string) {
>
> def_str = string;
>
> }
>
> /**
>
> * @param string
>
> */
>
> public void setName(String string) {
>
> name = string;
>
> }
>
> /**
>
> * @param string
>
> */
>
> public void setTable(String string) {
>
> table = string;
>
> }
>
> }
>
>
>
> The TLD file looks like this:
>
> <?xml version="1.0" encoding="ISO-8859-1" ?>
>
> <!DOCTYPE taglib PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library
> 1.1//EN"
>
> "http://java.sun.com/j2ee/dtds/web-jsptaglibrary_1_1.dtd";>
>
> <taglib>
>
> <tlibversion>1.0</tlibversion>
>
> <jspversion>1.1</jspversion>
>
> <shortname>tmstaglib</shortname>
>
> <info>Trinity Tag Libary for eTMS</info>
>
> <!--A Simple tag -->
>
> <tag>
>
> <name>dbcombobox</name>
>
> <tagclass>tags.DBCombobox</tagclass>
>
> <!--Body content can have a value of
>
> empty: no body
>
> JSP: body that is evaluated by container, then possibly processed by the tag
>
> tagdependent: body is only processed by tag; JSP in body is not evaluated.
>
> -->
>
> <bodycontent>empty</bodycontent>
>
> <info>This this combobox tag gets its lines from a db query.</info>
>
> <!-- Optional attributes -->
>
> <attribute>
>
> <name>colum</name>
>
> <required>true</required>
>
> <rtexprvalue>true</rtexprvalue>
>
> </attribute>
>
> <attribute>
>
> <name>table</name>
>
> <required>true</required>
>
> <rtexprvalue>true</rtexprvalue>
>
> </attribute>
>
> <attribute>
>
> <name>name</name>
>
> <required>true</required>
>
> <rtexprvalue>false</rtexprvalue>
>
> </attribute>
>
> <attribute>
>
> <name>css_class</name>
>
> <required>true</required>
>
> <rtexprvalue>true</rtexprvalue>
>
> </attribute>
>
> <attribute>
>
> <name>def_str</name>
>
> <required>true</required>
>
> <rtexprvalue>true</rtexprvalue>
>
> </attribute>
>
> </tag>
>
> </taglib>
>
>
>
> My web.xml looks like this:
>
> <?xml version="1.0" encoding="ISO-8859-1"?>
> <!DOCTYPE web-app PUBLIC
> "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
> "http://java.sun.com/dtd/web-app_2_3.dtd";
> >
> <web-app>
> <context-param>
> <param-name>ENGLISH</param-name>
> <param-value>TRINITY - eTMS - Financial-Management WORLDWIDE
> </param-value>
> </context-param>
> <context-param>
> <param-name>GERMAN</param-name>
> <param-value>TRINITY - eTMS - Financial-Management WORLDWIDE
> </param-value>
> </context-param>
> <context-param>
> <param-name>FRENCH</param-name>
> <param-value>TRINITY - eTMS - Financial-Management WORLDWIDE
> </param-value>
> </context-param>
> <context-param>
> <param-name>SMALL_LOGO</param-name>
> <param-value>images/logo_small.gif</param-value>
> </context-param>
> <context-param>
> <param-name>SMALL_LOGO_WIDTH</param-name>
> <param-value>30</param-value>
> </context-param>
> <context-param>
> <param-name>SMALL_LOGO_HEIGHT</param-name>
> <param-value>27</param-value>
> </context-param>
> <taglib>
> <taglib-uri>/tags/tmstaglib</taglib-uri>
> <taglib-location>/WEB-INF/tmstaglib.tld</taglib-location>
> </taglib>
> </web-app>
>
>
> and in the jsp I inserted this:
>
> <%@ taglib uri="/tags/tmstaglib" prefix="tmstl" %>
>
> <td>
>
> <tmstl:dbcombobox colum="siso" table="TMS_FPVIKLP" name="chf"
> css_class="selectboxSmall" def_str="<%=chf%>" />
>
> </td>
>
>
>
> The Error Message of Tomcat 4.1.27 is:
>
> java.lang.NoClassDefFoundError: javax/servlet/jsp/JspContext
> at java.lang.Class.getDeclaredMethods0(Native Method)
> at java.lang.Class.privateGetDeclaredMethods(Class.java:1647)
> at java.lang.Class.getDeclaredMethods(Class.java:1131)
> at java.beans.Introspector$1.run(Introspector.java:1126)
> at java.security.AccessController.doPrivileged(Native Method)
> at java.beans.Introspector.getPublicDeclaredMethods(Introspector.java:1124)
> at java.beans.Introspector.getTargetMethodInfo(Introspector.java:989)
> at java.beans.Introspector.getBeanInfo(Introspector.java:370)
> at java.beans.Introspector.getBeanInfo(Introspector.java:144)
> at
> org.apache.jasper.compiler.Generator$TagHandlerInfo.(Generator.java:1946)
> at
> org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:10
> 93)
> at org.apache.jasper.compiler.Node$CustomTag.accept(Node.java:707)
> at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:1028)
> at org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:1070)
> at org.apache.jasper.compiler.Node$Visitor.visit(Node.java:1076)
> at org.apache.jasper.compiler.Node$Root.accept(Node.java:232)
> at org.apache.jasper.compiler.Node$Nodes.visit(Node.java:1028)
> at org.apache.jasper.compiler.Generator.generate(Generator.java:1917)
> at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:242)
> at org.apache.jasper.compiler.Compiler.compile(Compiler.java:369)
> at
> org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:4
> 73)
> at
> org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:1
> 90)
> at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:295)
> at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:241)
> at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> at
> org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Application
> FilterChain.java:247)
> at
> org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterCh
> ain.java:193)
> at
> org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.ja
> va:256)
> at
> org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
> at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
> at
> org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.ja
> va:191)
> at
> org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
> at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
> at
> org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2416)
> at
> org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180
> )
> at
> org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.
> java:171)
> at
> org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invok
> eNext(StandardPipeline.java:641)
> at
> org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172
> )
> at
> org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invok
> eNext(StandardPipeline.java:641)
> at
> org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
> at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
> at
> org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java
> :174)
> at
> org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invok
> eNext(StandardPipeline.java:643)
> at
> org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
> at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
> at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
> at
> org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:601)
> at
> org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConne
> ction(Http11Protocol.java:392)
> at
> org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565)
> at
> org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.jav
> a:619)
> at java.lang.Thread.run(Thread.java:534)
--
Kris Schneider <mailto:[EMAIL PROTECTED]>
D.O.Tech <http://www.dotech.com/>
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