Setting and getting properties is done using the setPropertyValue(s) and getPropertyValue(s) methods that both come with a couple of overloaded variants. They're all described in more detail in the JavaDoc Spring comes with. What's important to know is that there are a couple of conventions for indicating properties of an object. A couple of examples:

Below you'll find some examples of working with the BeanWrapper to get and set properties.

Note: this part is not important to you if you're not planning to work with the BeanWrapper directly. If you're just using the DataBinder and the BeanFactory and their out-of-the-box implementation, you should skip ahead to the section about PropertyEditors.

Consider the following two classes:

public class Company {
    private String name;
    private Employee managingDirector;

    public String getName()	{ 
        return this.name; 
    }
    public void setName(String name) { 
        this.name = name; 
    } 
    public Employee getManagingDirector() { 
        return this.managingDirector; 
    }
    public void setManagingDirector(Employee managingDirector) {
        this.managingDirector = managingDirector;
    }
}

public class Employee {
    private float salary;

    public float getSalary() {
        return salary;
    }
    public void setSalary(float salary) {
        this.salary = salary;
    }
}

The following code snippets show some examples of how to retrieve and manipulate some of the properties of instantiated: Companies and Employees

Company c = new Company();
BeanWrapper bwComp = BeanWrapperImpl(c);
// setting the company name...
bwComp.setPropertyValue("name", "Some Company Inc.");
// ... can also be done like this:
PropertyValue v = new PropertyValue("name", "Some Company Inc.");
bwComp.setPropertyValue(v);

// ok, let's create the director and tie it to the company:
Employee jim = new Employee();
BeanWrapper bwJim = BeanWrapperImpl(jim);
bwJim.setPropertyValue("name", "Jim Stravinsky");
bwComp.setPropertyValue("managingDirector", jim);

// retrieving the salary of the managingDirector through the company
Float salary = (Float)bwComp.getPropertyValue("managingDirector.salary");

Spring heavily uses the concept of PropertyEditors. Sometimes it might be handy to be able to represent properties in a different way than the object itself. For example, a date can be represented in a human readable way, while we're still able to convert the human readable form back to the original date (or even better: convert any date entered in a human readable form, back to Date objects). This behavior can be achieved by registering custom editors, of type java.beans.PropertyEditor. Registering custom editors on a BeanWrapper or alternately in a specific Application Context as mentioned in the previous chapter, gives it the knowledge of how to convert properties to the desired type. Read more about PropertyEditors in the JavaDoc of the java.beans package provided by Sun.

A couple of examples where property editing is used in Spring

Spring has a number of built-in PropertyEditors to make life easy. Each of those is listed below and they are all located in the org.springframework.beans.propertyeditors package. Most, but not all (as indicated below), are registered by default by BeanWrapperImpl. Where the property editor is configurable in some fashion, you can of course still register your own variant to override the default one:

Spring uses the java.beans.PropertyEditorManager to set the search path for property editors that might be needed. The search path also includes sun.bean.editors, which includes PropertyEditors for Font, Color and all the primitive types. Note also that the standard JavaBeans infrastructure will automatically discover PropertyEditors (without you having to register them) if they are in the same package as the class they handle, and have the same name as that class, with 'Editor' appended.

Besides the features you've seen in the previous sections there a couple of features that might be interesting to you, though not worth an entire section.