Spring – Setter Injection with Non-String Map

Dependency Injection is the main functionality provided by Spring IOC(Inversion of Control). The Spring-Core module is responsible for injecting dependencies through either Constructor or Setter methods. In Setter Dependency Injection(SDI) the dependency will be injected with the help of setters and getters methods. A bean-configuration file is used to set DI as SDI in the bean. For this, the property to be set with the SDI is declared under the <property> tag in the bean-config file. A Collection in java is a group of individual objects. Spring framework provides us facility of Setter injection using the following Collections:

• List
• Map
• Set

Implementation

The map will have both key and value as non-strings. Key will be Employee which has the following fields:

• Name
• Employee ID
• Department

Value will be Address which has the following parameters:

• House No.
• Pincode
• State
• Country

A. Company.java

A company has a list of employees.

Java

// Java Program to Illustrate Company Class

package com.geeksforgeeks.org;

// Importing required classes
import com.geeksforgeeks.org.Address;
import com.geeksforgeeks.org.Employee;
import java.util.*;
import java.util.Map.Entry;

// Class
public class Company {

    // Class member variable
    private Map<Employee, Address> employees;

    // Method
    public void display()
    {
        // Iterating over Map using for each loop
        for (Map.Entry<Employee, Address> entry :
             employees.entrySet()) {

            // Print statement
            System.out.println(
                "Employee Data ->"
                + entry.getKey().toString() + " Address ->"
                + entry.getValue().toString());
        }
    }
}

B. Employee.java

Java

// Java Program to Illustrate Employee Class

package com.geeksforgeeks.org;

// Importing required classes
import com.geeksforgeeks.org.Address;

// Class
public class Employee {

    // Class data members
    private String name;
    private String employeeID;
    private String department;

    public Employee(String name, String employeeID,
                    String department)
    {
        // This keyword refers to current instance itself
        this.name = name;
        this.employeeID = employeeID;
        this.department = department;
    }

    // Method
    // Overriding toString() method
    public String toString()
    {
        return ("[" + name + "," + employeeID + ","
                + department + "]");
    }
}

C. Address.java

Java

// Java Program to Illustrate Address Class

package com.geeksforgeeks.org;

// Class
public class Address {

    // Class data members
    private String houseNo;
    private String pincode;
    private String state;
    private String country;

    // Constructor
    public Address(String houseNo, String pincode,
                   String state, String country)
    {
        super();
        this.houseNo = houseNo;
        this.pincode = pincode;
        this.state = state;
        this.country = country;
    }

    // Method
    // Overriding toString() method
    public String toString()
    {
        return "[" + houseNo + "," + pincode + "," + state
            + "," + country + "]";
    }
}

D. applicationContext.xml

Configuration file for our project.

Java

<?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="employee1" class="com.geeksforgeeks.org.Employee">
      <property name="name" value="Sahil"></property>
      <property name="employeeID" value="101"></property>
      <property name="department" value="Game development"></property>
    </bean>
      <bean id="address1" class="com.geeksforgeeks.org.Address">
      <property name="houseNo" value="2"></property>
      <property name="pincode" value="110111"></property>
      <property name="state" value="Bihar"></property>
      <property name="country" value="India"></property>
    </bean>

    <bean id="company" class="com.geeksforgeeks.org.Company">
      <map>
      <entry key-ref="employee1" value-ref="address1"></entry>
      </map>
      </property>
    </bean>

</beans>

E. Test.java

Main file for running our project.

Java

// Java Program to Illustrate Application Class

package com.geeksforgeeks.org;

// importing required classes
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;

// Application class
// Main class
public class Test {

    // Main driver method
    public static void main(String[] args)
    {
        // Creating a class path resource
        Resource resource = new ClassPathResource(
            "applicationContext.xml");

        // Creating an object of Beanfactory class
        BeanFactory factory = new XmlBeanFactory(resource);

        // Creating an object of Employee class
        Company c = (Company)factory.getBean("company");

        // Calling print() method inside main() method
        c.display();
    }
}

Output:

Employee Data -> [Sahil, 101, Game development], Address -> [2, 110111, Bihar, India]