Introduction to Spring - Spring Enterprise Recipes: A Problem Solution Approach - page 33

Solution
In Spring 2.0 and later, a bean's scope is set in the scope attribute of the <bean> element. By default,
Spring creates exactly one instance for each bean declared in the IoC container, and this instance will
be shared in the scope of the entire IoC container. This unique bean instance will be returned for all
subsequent getBean() calls and bean references. This scope is called singleton , which is the default
scope of all beans. Table 1-2 lists all valid bean scopes in Spring.

Table 1-2. Valid Bean Scopes in Spring

Scope Description

singleton Creates a single bean instance per Spring IoC container

prototype

Creates a new bean instance each time when requested

request Creates a single bean instance per HTTP request; valid only in the context of a web

application

session Creates a single bean instance per HTTP session; valid only in the context of a web

application

globalSession

Creates a single bean instance per global HTTP session; valid only in the context of a
portal application

How It Works
To demonstrate the concept of bean scope, consider a shopping cart example in your shop application.
First, you create the ShoppingCart class as follows:

package com.apress.springenterpriserecipes.shop;
...
public class ShoppingCart {

private List<Product> items = new ArrayList<Product>();

public void addItem(Product item) {
items.add(item);
}

public List<Product> getItems() {
return items;
}
}