外文翻译-JSP应用框架(8)

用于毕业设计外文翻译

JavaBeans:

JavaBeans are Java classes which conform to a set of design patterns that make them easier to use with development tools and other components.

DEFINITION A JavaBean is a reusable software component written in Java. To qualify as a JavaBean, the class must be concrete and public, and have a noargument constructor. JavaBeans expose internal fields as properties by providing public methods that follow a consistent design pattern. Knowing that the property names follow this pattern, other Java classes are able to use introspection to discover and manipulate JavaBean properties.

The JavaBean design patterns provide access to the bean’s internal state through two flavors of methods: accessors are used to read a JavaBean’s state; mutators are used to change a JavaBean’s state.

Mutators are always prefixed with lowercase token set followed by the property name. The first character in the property name must be uppercase. The return value is always void—mutators only change property values; they do not retrieve them. The mutator for a simple property takes only one parameter in its signature, which can be of any type. Mutators are often nicknamed setters after their prefix. The mutator method signature for a weight property of the type Double would be:

public void setWeight(Double weight)

A similar design pattern is used to create the accessor method signature. Accessor methods are always prefixed with the lowercase token get, followed by the property name. The first character in the property name must be uppercase. The return value will match the method parameter in the corresponding mutator. Accessors for simple properties cannot accept parameters in their method signature. Not surprisingly, accessors are often called getters.

The accessor method signature for our weight property is：

public Double getWeight()

If the accessor returns a logical value, there is a variant pattern. Instead of using the lowercase token get, a logical property can use the prefix is, followed by the property name.