Spring Tutorials

There are following some steps to create Spring application in Eclipse as given below.

Step1. First You can download the latest version of JDK from Oracle's Java site, You will find instructions for installing JDK in downloaded files, follow the given instructions to install and configure the setup. Finally set PATH and JAVA_HOME environment variables on your System.

Step2. Now you can download the latest version of Eclipse IDE below link. Because All the examples in this tutorial have been written using Eclipse IDE. So I would suggest you should have latest version of Eclipse installed on your machine.

Eclipse is a exe file so you don't need to install the setup. you can download Eclipse and unzip this to a specific location on your system. now Run the exe file your eclipse was started. as seen below.

Step3. Now you create a simple Java Project using Eclipse IDE. Follow the option File -> New -> Project and finally select Java Project wizard from the wizard list. Now name your project as FirstSpringApplication using the wizard window as given below:

If your project create successfully, then you have seen the following content in your project Explorer.

Step4. Now add spring jar in your project, To do this, right click on your project name FirstSpringApplication and then follow the following option available in context menu: Build Path -> Configure Build Path to display the Java Build Path window as given below. There are mainly three jar files required to run this application, To load the jar files in eclipse IDE, Right click on your project - Build Path - Add external archives - select all the required jar files - finish.

1. org.springframework.core-3.0.1.RELEASE-A
2. com.springsource.org.apache.commons.logging-1.1.1
3. org.springframework.beans-3.0.1.RELEASE-A

Step5. Now you create simply java file with any name. First we need to create a package with any name like com.r4r. To do this, Right click on src in package explorer section and follow the option : New -> Package. and then Right click on package(com.r4r) - New - class - Write the class name e.g. Employee - finish. Write the following code:

package com.r4r;
public class Employee {
private String name;//variable declaration.
private int age;
public String getName() {  //getter and setter.
    return name;  
}  
public void setName(String name) {  
    this.name = name;  
}  
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
} 
 public void print(){  //This is a metod.
    System.out.println("Name: "+name);  
    System.out.println("Age: "+age); 
}
}

Employee is simple bean class, containing only two property name and age with its getters and setters method. This class contains one extra method named print() that prints the employee name and age. The name and age of the employee will be provided by the xml file.

Step6. Now create the xml file click on src- new -file -give the file name like applicationContext.xml then finish.

<?xml version="1.0" encoding="UTF-8"?>  
<beans  
    xmlns="http://www.springframework.org/schema/beans"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
    xmlns:p="http://www.springframework.org/schema/p"  
    xsi:schemaLocation="http://www.springframework.org/schema/beans  
    http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">  
<bean id="emp" class="com.r4r.Employee">  
<property name="name" value="John Smith"></property>  
<property name="age" value="25"></property> 
</bean>  
</beans>  

The bean element is used to define the bean for the given class. The property subelement of bean specifies the property of the Employee class named name and age. The value specified in the property element will be set in the Employee class object by the IOC container.

Step7.Now Create the java Main class(Demo.java), Here we are getting the object of Employee class from the IOC container using the getBean() method of BeanFactory.

package com.r4r;
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;  
public class Demo {
public static void main(String[] args) {  
Resource resource=new ClassPathResource("applicationContext.xml");  
BeanFactory factory=new XmlBeanFactory(resource);  
Employee employee=(Employee)factory.getBean("emp");  
employee.print();  
}  
}  

Here Resource object represents the information of applicationContext.xml file. The Resource is the interface and the ClassPathResource is the implementation class of the Reource interface. The BeanFactory is responsible to return the bean. The XmlBeanFactory is the implementation class of the BeanFactory. There are many methods in the BeanFactory interface. One method is getBean(), which returns the object of the associated class.

Now run the Application you see the following output