I have followed the book example but there is an error showed up. Please give me the idea how to solve it. Thanks a lot.
Here is the coding:
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core_rt" %>
<%@ taglib prefix="sql" uri="http://java.sun.com/jstl/sql_rt" %>
<sql:setDataSource var="datasource"
driver="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost/publish"
user="phirun" password="amazon" />
<c:if test="${param.title != null}">
<sql:update dataSource="${dataSource}">
INSERT INTO book (title,price) values(?,?)
<sql:param value="$(param.title)"/>
<sql:param value="$(param.price)"/>
</sql:update>
</c:if>
<sql:query var="books" dataSource="${datasource}">
select id,title,price from book
</sql:query>
<html>
<head>
<title> A first JSP database </title>
</head>
<body>
<form method="post">
<table border="1">
<tr>
<td> id </td>
<td> title </td>
<td> price </td>
</tr>
<c:forEach items="${books.rows}" var="row">
<tr>
<td> <c:out value="${row.id}" /> </td>
<td> <c:out value="${row.title}" /> </td>
<td> <c:out value="${row.price}" /> </td>
</tr>
</c:forEach>
<tr>
<td> </td>
<td> <input type="text" name="title" size="30" /> </td>
<td> <input type="text" name="price" size="5" /> </td>
</tr>
<tr>
<td colspan="3" align="center">
<input type="submit" value="Save" />
</td>
</tr>
</table>
</form>
</body>
</html>
My JSP is just pull the database which is book database and show book title and price on the page. The user is able to enter the new book title and price then click save to update the database. The browser shows the error when clicking the Save Button as follows: javax.servlet.ServletException: 'dataSource' is null
at org.apache.jasper.runtime.PageContextImpl.handlePa geException(PageContextImpl.java:682)
at org.apache.jsp.helloJSP.bookDB2_jsp._jspService(bo okDB2_jsp.java:122)
at org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:136)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:856)
at org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:320)
at org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:293)
at org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:240)
at javax.servlet.http.HttpServlet.service(HttpServlet .java:856)
at org.apache.catalina.core.ApplicationFilterChain.in ternalDoFilter(ApplicationFilterChain.java:286)
at org.apache.catalina.core.ApplicationFilterChain.do Filter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invo ke(StandardWrapperValve.java:256)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:562)
at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:974)
at org.apache.catalina.core.StandardContextValve.invo ke(StandardContextValve.java:205)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:562)
at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:974)
at org.apache.catalina.core.StandardHostValve.invoke( StandardHostValve.java:177)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.valves.ErrorDispatcherValve.in voke(ErrorDispatcherValve.java:171)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:149)
at org.apache.catalina.valves.ErrorReportValve.invoke (ErrorReportValve.java:172)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:149)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:562)
at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:974)
at org.apache.catalina.core.StandardEngineValve.invok e(StandardEngineValve.java:156)
at org.apache.catalina.core.StandardValveContext.invo keNext(StandardValveContext.java:151)
at org.apache.catalina.core.StandardPipeline.invoke(S tandardPipeline.java:562)
at org.apache.catalina.core.ContainerBase.invoke(Cont ainerBase.java:974)
at org.apache.coyote.tomcat5.CoyoteAdapter.service(Co yoteAdapter.java:203)
at org.apache.coyote.http11.Http11Processor.process(H ttp11Processor.java:637)
at org.apache.coyote.http11.Http11Protocol$Http11Conn ectionHandler.processConnection(Http11Protocol.jav a:488)
at org.apache.tomcat.util.net.TcpWorkerThread.runIt(P oolTcpEndpoint.java:568)
at org.apache.tomcat.util.threads.ThreadPool$ControlR unnable.run(ThreadPool.java:631) at java.lang.Thread.run(Thread.java:536)
What have I done wrong? How to debug this program?
Chapter 3 problem (bookDB2.jsp)
