Developing Application-Specific Database Components
The
SQLCommandBean
class described in
this
chapter can be used for application-specific components that access a
database. The bean is used like this:
SQLCommandBean sqlCommandBean = new SQLCommandBean( ); sqlCommandBean.setConnection(dataSource.getConnection( )); String sql = "SELECT * FROM Employee WHERE UserName = ?"); sqlCommandBean.setSqlValue(sql); List values = new ArrayList( ); values.add(userName); sqlCommandBean.setValues(values); Result result = sqlCommandBean.executeQuery( );
Chapter 19 includes a more advanced example of an
application-specific bean (the
EmployeeRegisterBean
) that uses the
SQLCommandBean
.
You can also use these classes in your application-specific custom actions. One example is the custom action that’s mentioned in Chapter 12 as an alternative to the generic database actions for inserting or updating employee information:
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql" %> <%@ taglib prefix="myLib" uri="mytaglib" %> <myLib:saveEmployeeInfo dataSource="${appDataSource}" /> <%-- Get the new or updated data from the database --%> <sql:query var="newEmpDbInfo"="${example}" scope="session"> SELECT * FROM Employee WHERE UserName = ? <sql:param value="${param.userName}" /> </sql:query> <%-- Redirect to the confirmation page --%> <c:redirect url="confirmation.jsp" />
Example 24-8 shows one way to implement this custom action.
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