JavaServer Pages, Second Edition

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 18 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 11 as an alternative to the generic database actions for inserting or updating employee information:

<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core" %>
<%@ taglib prefix="sql" uri="http://java.sun.com/jstl/sql" %>
<%@ taglib prefix="myLib" uri="/mytaglib" %>
                 
               <myLib:saveEmployeeInfo dataSource="example" />
                 
<%-- Get the new or updated data from the database --%>
<sql:query var="newEmpDbInfo" dataSource="${example}" scope="session">
  SELECT * FROM Employee 
    WHERE UserName = ?
  <sql:param value="${param.userName}" />
</sql:query>
  
<%-- Redirect to the confirmation page --%>
<c:redirect url="confirmation.jsp" />

Example 23-8 shows one way to implement this custom action.