Another way to access database without using applicationContext.xml is as follows :

DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName("oracle.jdbc.driver.OracleDriver");
dataSource.setUrl("jdbc:oracle:thin:@localhost:1521:XE");
dataSource.setUsername("username");
dataSource.setPassword("pwd");
JdbcTemplate jt = new JdbcTemplate(dataSource);

Just place it in your controller and you're done. ;)

Alright, now we'll move on to database connectivity. First create a table for our login, we only need 2 attributes, username and password, name the table as login or any name you like. In this example, i used Oracle. Basically its the same with any other database, MySQL..etc.. The difference is the class driver name and such. Here we'll simplify things by NOT using validator..and use javascript to validate fields. Much much easier..unless we're familiar with validators.

This example is done as per my understanding. You might approach this example in different way, which im sure there are lots. So if you think there's another way to do this, please feel free to comment. Share the knowledge :P

We're dropping off validator class, so you can dereference it from your bean by removing the <property name="validator"><ref bean="loginValidator"/></property> line from dispatcher-servlet.xml. Theres no further changes in that xml file. Create a simple jsp, name it as failure. jsp.

There's 2 ways to database connectivity, one is by normal JDBC, the other using Hibernate. This example uses JDBC (i'm too lazy to learn hibernate now, so i use JDBC :P) This connectivity using Springs is slightly different from Struts. So whatever you learnt in Struts u can forget it temporarily. Spring uses JDBC template in handling data access. This is not the only way. There are other ways, but so far ive found the template to be most used. Just remember to keep SpringSource website as your best friend.

One advantage of JdbcTemplate is it cleans-up the resources automatically, e.g. release the database connections. The template class of Spring is JdbcTemplate. A dataSource is provided inside JdbcTemplate.

We'll create 2 java classes, one interface and the other implementing it. We can also use just one class instead of 2. But i'll show that in the Part 4 series. So for now i'll stick to 2 classes.

Create a package called Connection. Create datacon.java in that package. (Actually this is not really the way to declare classes or packages. But for our understanding's sake we differentiate it this way) Add these lines :

public interface datacon {
public DataSource dbcon(); //don't forget to import javax.sql.DataSource
}

Create dataconimpl.java inside the same package. Add the following lines :

public class dataconimpl implements datacon{
private DataSource dataSource; //don't forget to import javax.sql.DataSource
public void setDataSource(DataSource ds) {
dataSource = ds;
}
public DataSource dbcon() {
return dataSource;
}
}

These 2 classes are referred from this page.

Now we'll see on applicationContext.xml. If you notice in that file, theres few lines of code commented. For some reason those codes are not working properly, so ive tried different way. That will be explained later once ive managed to run the application successfully. So in this file, add these lines,

<bean id="datacon" class="Connection.dataconimpl">
<property name="dataSource">
<ref local="dataSource"/>
</property>
</bean>

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="oracle.jdbc.driver.OracleDriver"/>
<property name="url" value="jdbc:oracle:thin:@localhost:1521:XE"/> <!-- XE - Oracle express edition -->
<property name="username" value="system"/> <!-- according to your local Oracle name, password -->
<property name="password" value="123456"/>
</bean>

Notice the highlighted dataSource? Both name are the same. We're goin to refer that datacon bean in our controller, and that datacon bean is referring to dataSource. Now let's update our LoginFormController.java. Remember we're not using validator in this example. Create your own javascript for field validation.

Now we'll see both database connectivity as well as linking failure page. Create a string variable to hold your jsp page name. .jsp extension has already resolved in the dispatcher-servlet.xml. (bean id="viewResolver") So you dont need to specify .jsp. The code will be short as we're just goin to check whether the record exists or not. If you have any other logic besides this, let me know :)

Comment out the previous codes. Then add the following codes :

String status = "success";
Resource res = new ClassPathResource("../applicationContext.xml");
BeanFactory factory = new XmlBeanFactory(res);
datacon bean1 = (datacon) factory.getBean("datacon");
DataSource ds = bean1.dbcon();
JdbcTemplate jt = new JdbcTemplate(ds);

status variable is to hold the name of the jsp page. success is the success.jsp. you can initialise it with any string. ClassPathResource reads the applicationContext.xml. It'll read the connections defined inside. Some codes online refers the xml file without the "../" before applicationContext.xml. So improvise to see which suits you best. datacon in the getBean() is the bean that you've defined in applicationContext.xml. JdbcTemplate will be used as our data access method.

Add these lines after the ones above :

LoginFormBean loginBean = (LoginFormBean) command;

int count = jt.queryForInt("select count(*) from login where username = ? and password=?", new Object[]{loginBean.getName(), loginBean.getPassword()});
if (count==0){
status = "failure";
}else{
status = "success";
}
return new ModelAndView(status);

count will keep the number of records according to that username and password. What this code does is merely checking if there's any record based on the username and password given. Like i said, you can use any logic to check for login details. I used counting records. The select statement is somewhat same as PreparedStatement. ? as the wildcard to get user input or values. new Object[]{} is like setXXX() (e.g setString) within those curly braces, you add as many parameters you want according to the number of question marks. failure is failure.jsp. So this onSubmit() function will return the view according to the status whether it's failure or success. Same like our execute() in Struts :P So you can remove the successView property from dispatcher-servlet.xml as we don't really need them.

Your imports for this LoginFormController.java is like below :

import Bean.LoginFormBean;
import Connection.datacon;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.validation.BindException;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.SimpleFormController;

No changes required for index.jsp page except adding on javascript validation if you want to. Run the application and see the results. :)

Now let's try some validation for our dummy project. Use back the same project from the previous post. Remember the validation that we used for our Struts before? (Hope u do :P) Its somewhat same as this one.

First of all, get the spring-form.tld file from the spring.jar file. Extract it and you should be able to see that file residing inside the META-INF folder. Create a folder under WEB-INF in your project, name it as tld. Copy the tld file and paste it inside the tld folder. If you want to know more about the file, visit this. So your directory should be somewhat like below.

String name;

String password;
public String getName() {

return name;

}
public void setName(String name) {

this.name = name;

}
public String getPassword() {

return password;

}
public void setPassword(String password) {

this.password = password;

}

}

LoginFormBean loginBean = (LoginFormBean) command;

System.out.println("Username: " + loginBean.getName());

System.out.println("Password: " + loginBean.getPassword());

return new ModelAndView("success"); //success here is the success.jsp

Now for our validator file. Create LoginFormValidator.java under Validator package. Add this code. Make sure you implement Validator. (LoginFormValidator implements Validator)

LoginFormBean loginBean;
@Override

public boolean supports(Class clazz) {

return clazz.equals(LoginFormBean.class);

}
@Override

public void validate(Object commandObject, Errors errors) {
loginBean = (LoginFormBean) commandObject;

ValidationUtils.rejectIfEmptyOrWhitespace(errors, "name", "name", "Name is required.");

ValidationUtils.rejectIfEmptyOrWhitespace(errors, "password", "password", "Password is required.");

if (!errors.hasFieldErrors("name") && !errors.hasFieldErrors("password")) {

if ((loginBean.getPassword().equals("password") == false) && (loginBean.getName().equals("admin") == false)) {

errors.rejectValue("name", "name", "Incorrect Login Details!");

}

}

}

The uri "spring" is the same as the one in <taglib> inside web.xml. Make sure the name is same :P

<spring:form method="post" action="" commandName="login">

<p>

User name :

<spring:input path="name"/>

</p>

<p>

Password :

<spring:password path="password" />

</p>

<p>

<spring:errors cssClass="error" path="*"/><br>

</p>

<p>

<p>
<spring:errors cssClass="error" path="*"/><br>
</p>
<p>
<input type="submit" name="Submit" value="Submit" />
</p>
</spring:form>

Let's continue with Spring by trying out a new application - Login. We'll enhance this all the way. Adding on sessions and etc... for now, lets create a dummy login.

Create project as shown before. Don't forget to change the *.htm to *.do when creating a new project. Edit the dispatcher-servlet.xml to become .do. We use back the index.jsp as our login page. Create another jsp namely success.jsp in WEB-INF/jsp.

Add the following code to index.jsp. This is our login page.

<html>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<form id="form1" name="form1" method="post" action="">
<p>
User name :
<input type="text" name="name"/>
</p>
<p>
Password :
<input type="password" name="password" />

</p>
<p>
<input type="submit" name="Submit" value="Submit" />
</p>
</form>
</html>


Create 3 packages - Bean, Controller, Validator ( will be used in next tutorial). Under Bean package, create a java class - LoginFormBean.java. Leave it empty (empty class). Under Controller package, create a java class - LoginFormController.java. You can create this file by doing the following. Right click the project or from the file menu -> New File -> Spring Framework -> Simple Form Controller . The codes will be generated for you.

Remove the doSubmitAction and uncomment onSubmit function. Leave it as it is. Edit dispatcher-servlet.xml. Add the following code.

<bean id="loginForm" class="Controller.LoginFormController">
<property name="sessionForm"><value>true<value></property>
<property name="commandName"><value>login</value></property>
<property name="commandClass"><value>Bean.LoginFormBean</value></property>
<property name="formView"><value>index</value></property>
<property name="successView"><value>success</value></property>
</bean>

<bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
<property name="mappings">
<map>
<entry key="/index.do">
<ref bean="loginForm"/>
</entry>
</map>
</property>
</bean>

Remove the indexcontroller part. Notice that loginForm in the urlMapping bean is the same as the one above. Quoting from here.

• commandClass—the class of the object that will be used to represent the data in this form. (tht is the bean)
  
• commandName—the name of the command object. (bean name)
  
• sessionForm—if set to false, Spring uses a new bean instance (i.e. command object) per request, otherwise it will use the same bean instance for the duration of the session.
• validator—a class that implements Spring's Validator interface, used to validate data that is passed in from the form.
• formView—the JSP for the form, the user is sent here when the controller initially loads the form and when the form has been submitted with invalid data. (input)
  
• successView—the JSP that the user is routed to if the form submits with no validation errors. (success)
  

Try and run your application. Make sure the login page appears. Next part of the tutorial will be the using validator..(like our struts)

After hours of figuring out how this Spring thingy works..finally came up with one simple app using controllers and stuff. So lets create an app to display values entered by user.

Jar files usually needed for Spring are :

• spring. jar
• standard.jar
• jstl.jar
• taglibs-string. jar
• commons-lang.jar
• commons-logging-1.1.jar
• spring-webmvc-2.5.jar
• log4j-1.2.14.jar

This app is done without using form bean. That will be another tutorial :P

Posted By - Lakshmi