Spring sample applications - Need Help

[Niranjan Deshpande]

Hi all,

I am following Sprign in Action 2.0 Though I am trying to read most of it, the problem is, the book does not have sample code, independent for each concept. It has a huge application called the Road Rantz, which if you try to configure, you end up getting annoyed as you never know what all jars it needs in it's build path. Also, you cannot touch the application unless you finish the comple book.

So far for chapters 1,2,4 I have been trying some sample independent code, targeted to the sections, as I read them. But chapter 5 onwards I am not able to do so. Like in chapter 5 for example, I am trying to use a jdbc template and a DAO object, and the spring's jdbc classes, data source for these templates. But I am not sure what to do and in which class? The code so far I wrote is:

package com.springinaction.db;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;

public class DbApplication {
 
/**
 * @param args
 */
public static void main(String[] args) {
ApplicationContext ctx2 = new FileSystemXmlApplicationContext("./src/dbAccess.xml");
TestJdbcTemplate jdbcTemplate = (TestJdbcTemplate)ctx2.getBean("jdbcBean");
 

}
 
}

package com.springinaction.db;
 
public class Employee {

private String name;
private String location;
private String designation;
private String project;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public String getDesignation() {
return designation;
}
public void setDesignation(String designation) {
this.designation = designation;
}
public String getProject() {
return project;
}
public void setProject(String project) {
this.project = project;
}

 
}

package com.springinaction.db;

import org.springframework.jdbc.core.support.JdbcDaoSupport;

public class TestJdbcDao extends JdbcDaoSupport {
private static final String INSERT_DATA =
"insert into employee (id, name, designation, " +
"location, project) " +
"values (null, ?,?,?,?)";

public void saveEmployee(Employee employee) {
getJdbcTemplate().update(INSERT_DATA,
new Object[] { employee.getName(),employee.getDesignation(),
employee.getLocation(), employee.getProject() });
}
 
}

package com.springinaction.db;
 
import org.springframework.jdbc.core.JdbcTemplate;
 
public class TestJdbcTemplate {

private JdbcTemplate jdbcTemplate;
 
public JdbcTemplate getJdbcTemplate() {
return jdbcTemplate;
}
 
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
this.jdbcTemplate = jdbcTemplate;
}


 
}

<bean id="jdbcBean" class="com.springinaction.db.TestJdbcTemplate">
<property name="jdbcTemplate" ref="jdbcTemplate" />
</bean>

       <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="dataSource" />
   </bean>
   
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.hsqldb.jdbcDriver" />
<property name="url" value="jdbc:hsqldb:hsql://localhost/roadrantz/roadrantz" />
<property name="username" value="sa" />
<property name="password" value="" />
</bean>

After I run this application I can see this on the console.
INFO: Loaded JDBC driver: org.hsqldb.jdbcDriver

I want to connect to HSQL, and I am aware of starting this database's server and opening the HSQL's database manager window to create tables.

I want to try out the template and the jdbc stuff in spring using the above design/setup. HAve I written code at the correct places? Also, what should be the url property's value in above XML. My java application DbApplication is just going to insert a Employee object into the database, and read them

Please guide me on this.

[Christophe Verré]

Why don't you just try to use the DAO to see if the employee is saved ? It looks to me that you have an unnecessary TestJdbcTemplate, and an unused DAO. You could remove the TestJdbcTemplate, and use your DAO instead :

public class TestJdbcDao extends JdbcDaoSupport {
 
public void saveEmployee(Employee employee) {
String INSERT_DATA =
"insert into employee (id, name, designation, " +
"location, project) " +
"values (null, ?,?,?,?)";
 
getJdbcTemplate().update(INSERT_DATA,
new Object[] { employee.getName(),employee.getDesignation(),
employee.getLocation(), employee.getProject() });
}
}
}
 

<bean id="testJdbcDao" class="com.springinaction.db.TestJdbcDao">
<property name="dataSource" ref="dataSource" />
</bean>
   
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.hsqldb.jdbcDriver" />
<property name="url" value="jdbc:hsqldb:hsql://localhost/roadrantz/roadrantz" />
<property name="username" value="sa" />
<property name="password" value="" />
</bean>
 
public class DbApplication {
 
/**
 * @param args
 */
public static void main(String[] args) {
ApplicationContext ctx2 = new FileSystemXmlApplicationContext("./src/dbAccess.xml");
TestJdbcDao jdbcDao = (TestJdbcDao)ctx2.getBean("testJdbcDao");
Employee niranjan = new Employee();
// call setters...
jdbcDao.saveEmployee(niranjan);
}
}

[Christophe Verré]

To make it a bit more Springy, I'd make the DAO implement an interface, and use a separate class to access it. You'll understand its importance when you start sudying transactions.

public interface IEmployeeDao {
public void saveEmployee(Employee employee);
}
 
public class EmployeeDao extends JdbcDaoSupport implements IEmployeeDao {
 
public void saveEmployee(Employee employee) {
String INSERT_DATA =
"insert into employee (id, name, designation, " +
"location, project) " +
"values (null, ?,?,?,?)";
 
getJdbcTemplate().update(INSERT_DATA,
new Object[] { employee.getName(),employee.getDesignation(),
employee.getLocation(), employee.getProject() });
}
}
}
 
package com.springinaction.service;
public interface IEmployeeService {
public void saveEmployee(Employee employee);
}
 
package com.springinaction.service;
public class EmployeeServiceImpl implements IEmployeeService {
 
private IEmployeeDao empDao;
 
public void saveEmployee(Employee emp){
empDao.saveEmployee(emp);
}
 
public void setEmpDao(IEmployeeDao dao){
this.empDao = dao;
}
}
 

<bean id="employeeDao" class="com.springinaction.db.EmployeeDao">
<property name="dataSource" ref="dataSource" />
</bean>
 
<bean id="employeeService" class="com.springinaction.service.EmployeeServiceImpl">
<property name="empDao" ref="employeeDao" />
</bean>
   
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.hsqldb.jdbcDriver" />
<property name="url" value="jdbc:hsqldb:hsql://localhost/roadrantz/roadrantz" />
<property name="username" value="sa" />
<property name="password" value="" />
</bean>
 
public class DbApplication {
 
/**
 * @param args
 */
public static void main(String[] args) {
ApplicationContext ctx2 = new FileSystemXmlApplicationContext("./src/dbAccess.xml");
IEmployeeService employeeService = (TestJdbcDao)ctx2.getBean("employeeService");
Employee niranjan = new Employee();
// call setters...
employeeService.saveEmployee(niranjan);
}
}

[ March 07, 2008: Message edited by: Christophe Verre ]

[Niranjan Deshpande]

How about the value attribute of the URL property when I configure the data source? I want to use HSQL. Please help.


In case I use MS Access, I know that once can configure the ODBC source in Windows control panel, and link that name in the URL's vlaue field.

But how to do that for HSQL??
[ March 07, 2008: Message edited by: Niranjan Deshpande ]

[Christophe Verré]

Sorry, I don't know hsqldb's jdbc url format. You'll have to search into Hsqldb's documentation (like here)