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Spring - Setter Injection with Non-String Collection

When you want to perform setter injection with a collection that contains non-string values (like custom objects), Spring provides an efficient way to handle it. Let's consider an example where we want to inject a list of Book objects into a Library class.

Java Classes:

// Book.java
public class Book {
    private String title;

    public Book(String title) {
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

    @Override
    public String toString() {
        return "Book: " + title;
    }
}

// Library.java
public class Library {
    private List<Book> books;

    public void setBooks(List<Book> books) {
        this.books = books;
    }

    public void displayBooks() {
        for (Book book : books) {
            System.out.println(book);
        }
    }
}

Spring XML Configuration:

Create a beans.xml configuration file:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!-- Book beans -->
    <bean id="book1" class="Book">
        <constructor-arg value="The Great Gatsby"/>
    </bean>
    <bean id="book2" class="Book">
        <constructor-arg value="Moby Dick"/>
    </bean>

    <!-- Library bean with list injection -->
    <bean id="library" class="Library">
        <property name="books">
            <list>
                <ref bean="book1"/>
                <ref bean="book2"/>
            </list>
        </property>
    </bean>
</beans>

In the XML above, we define two Book beans and inject them into the Library bean using a <list> element.

Test the Configuration:

Create a main class to load the beans and test the configuration:

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

public class App {
    public static void main(String[] args) {
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        Library library = (Library) context.getBean("library");
        library.displayBooks();
    }
}

Running this main class should display:

Book: The Great Gatsby
Book: Moby Dick

In this example, we used a <list> for setter injection, but you can also use <set>, <map>, or <props> for other collection types. The process remains the same: define individual beans and reference them within the collection element.

Spring Setter Injection with non-string Collection example:

Description: Demonstrates how to use setter injection to inject a collection of non-string objects into a Spring bean.

Code:

public class MyBean {
    private Collection<CustomObject> myCollection;

    public void setMyCollection(Collection<CustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Injecting a Collection of non-string objects using Setter Injection in Spring:

Description: Illustrates how to inject a collection of non-string objects using setter injection in the Spring framework.

Code:

public class MyBean {
    private Collection<NonStringObject> myCollection;

    public void setMyCollection(Collection<NonStringObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Setter Injection with non-string Collection in Spring Framework:

Description: Guides on setter injection with a collection of non-string objects in the Spring framework.

Code:

public class MyBean {
    private Collection<CustomObject> myCollection;

    public void setMyCollection(Collection<CustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Spring Setter Injection for injecting a Collection of non-string dependencies:

Description: Demonstrates how to use setter injection to inject a collection of non-string dependencies in a Spring bean.

Code:

public class MyBean {
    private Collection<DependencyObject> dependencyCollection;

    public void setDependencyCollection(Collection<DependencyObject> dependencyCollection) {
        this.dependencyCollection = dependencyCollection;
    }
}

Using @Autowired with non-string Collection in Spring:

Description: Shows how to use @Autowired for injecting a collection of non-string objects in Spring using setter injection.

Code:

public class MyBean {
    private Collection<CustomObject> myCollection;

    @Autowired
    public void setMyCollection(Collection<CustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Setter-based injection of non-string Collection in Spring components:

Description: Demonstrates setter-based injection of a collection of non-string objects in Spring components.

Code:

@Component
public class MyComponent {
    private Collection<CustomObject> myCollection;

    @Autowired
    public void setMyCollection(Collection<CustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Injecting a Collection of custom objects using Setter Injection in Spring:

Description: Shows how to inject a collection of custom objects using setter injection in a Spring bean.

Code:

public class MyBean {
    private Collection<MyCustomObject> myCollection;

    public void setMyCollection(Collection<MyCustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Configuring Setter Injection for non-string Collection in Spring Beans:

Description: Guides on configuring setter injection for a collection of non-string objects in Spring beans.

Code:

@Component
public class MyComponent {
    private Collection<CustomObject> myCollection;

    @Autowired
    public void setMyCollection(Collection<CustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Spring Setter Injection for handling non-string elements in a Collection:

Description: Illustrates how to use setter injection for handling non-string elements in a collection in Spring.

Code:

public class MyBean {
    private Collection<NonStringElement> myCollection;

    public void setMyCollection(Collection<NonStringElement> myCollection) {
        this.myCollection = myCollection;
    }
}

Setter Injection with non-string Collection in Spring components:

Description: Demonstrates setter injection with a collection of non-string objects in Spring components.

Code:

@Component
public class MyComponent {
    private Collection<CustomObject> myCollection;

    @Autowired
    public void setMyCollection(Collection<CustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Using @Resource for Setter Injection with non-string Collection in Spring:

Description: Shows how to use @Resource for setter injection with a collection of non-string objects in Spring.

Code:

public class MyBean {
    private Collection<CustomObject> customObjectCollection;

    @Resource
    public void setCustomObjectCollection(Collection<CustomObject> customObjectCollection) {
        this.customObjectCollection = customObjectCollection;
    }
}

Spring Setter Injection for injecting dependencies as a non-string Collection:

Description: Demonstrates how to use setter injection for injecting dependencies as a collection of non-string objects in a Spring bean.

Code:

public class MyBean {
    private Collection<DependencyObject> dependencyCollection;

    public void setDependencyCollection(Collection<DependencyObject> dependencyCollection) {
        this.dependencyCollection = dependencyCollection;
    }
}

Setter-based injection with autowired non-string Collection in Spring:

Description: Demonstrates setter-based injection with autowired collection of non-string objects in Spring components.

Code:

@Component
public class MyComponent {
    private Collection<CustomObject> customObjectCollection;

    @Autowired
    public void setCustomObjectCollection(Collection<CustomObject> customObjectCollection) {
        this.customObjectCollection = customObjectCollection;
    }
}

Spring Setter Injection with different types of non-string Collections:

Description: Illustrates how to use setter injection with different types of collections (e.g., List, Set) containing non-string elements in Spring.

Code:

public class MyBean {
    private List<NonStringObject> myList;
    private Set<MyCustomObject> mySet;

    public void setMyList(List<NonStringObject> myList) {
        this.myList = myList;
    }

    public void setMySet(Set<MyCustomObject> mySet) {
        this.mySet = mySet;
    }
}

Injecting properties as a non-string Collection using Setter Injection in Spring:

Description: Shows how to use setter injection to inject properties as a collection of non-string objects in Spring beans.

Code:

public class MyBean {
    private Collection<MyPropertyObject> myCollection;

    public void setMyCollection(Properties properties) {
        // Convert properties to a collection of custom objects
        this.myCollection = convertPropertiesToCollection(properties);
    }
}

Configuring Spring beans with Setter Injection and non-string Collection:

Description: Guides on configuring Spring beans with setter injection and a collection of non-string objects.

Code:

@Component
public class MyComponent {
    private Collection<MyCustomObject> myCollection;

    @Autowired
    public void setMyCollection(Collection<MyCustomObject> myCollection) {
        this.myCollection = myCollection;
    }
}

Spring Setter Injection with non-string Collection of dependencies:

Description: Demonstrates how to use setter injection with a collection of dependencies as non-string objects in a Spring bean.

Code:

public class MyBean {
    private Collection<AnotherDependency> dependencyCollection;

    public void setDependencyCollection(Collection<AnotherDependency> dependencyCollection) {
        this.dependencyCollection = dependencyCollection;
    }
}

Setter Injection with non-string Collection for managing custom objects in Spring:

Description: Demonstrates setter injection with a collection of non-string objects for managing custom objects in Spring.

Code:

@Component
public class MyComponent {
    private Collection<MyCustomObject> customObjectCollection;

    @Autowired
    public void setCustomObjectCollection(Collection<MyCustomObject> customObjectCollection) {
        this.customObjectCollection = customObjectCollection;
    }
}

Handling non-string Collections with dependent objects in Spring Setter Injection:

Description: Guides on handling collections of non-string objects with dependent objects using setter injection in the Spring framework.

Code:

public class MyBean {
    private Collection<DependentObject> dependentObjectCollection;

    public void setDependentObjectCollection(Collection<DependentObject> dependentObjectCollection) {
        this.dependentObjectCollection = dependentObjectCollection;
    }
}