The technical principles and applications of the Commons Beanutils Core framework in the Java class library

Commons Beanutils Core (referred to as Beanutils) is a lightweight framework widely used in the Java class library. It provides a simple way to operate the JavaBean object, especially in terms of attributes.Below will introduce the technical principles and applications of Beanutils, and provide some Java code examples. 1. Technical principles The technical principles of Beanutils are mainly based on the Java reflection mechanism and the Introspect. 1. Reflex mechanism: Pet reflection is the strong characteristics of the Java language itself. It can dynamically obtain the information of the class and call the class method, access/modify field fields during runtime.Beanutils uses the reflex mechanism to obtain information such as the attributes of JavaBean (Getter/Setter), fields and other information, and perform corresponding operations. 2. Internal provincial mechanism: Internal province is part of the Javaans specification. It provides a mechanism and method of automatic analysis of JavaBean's attributes and methods.BEANUTILS uses the internal provincial mechanism to handle the attributes of JavaBean, such as obtaining attribute types, obtaining/setting attribute values, etc. Within Beanutils, by combining reflection and internal provinces, the attribute copy, attribute value conversion, attribute mapping of the JavaBean object can be realized. 2. Application scenario Beanutils is suitable for the following application scenarios: 1. Copy of attributes: Beanutils provides a convenient method `CopyProperties`, you can copy the attribute of one JavaBean to another JavaBean without manually set the value of the attribute one by one. Example code: SourceBean source = new SourceBean(); // Set the attribute value of the source object source.setName("Alice"); source.setAge(25); TargetBean target = new TargetBean(); // Copy the attributes of the source object to the target object BeanUtils.copyProperties(target, source); System.out.println (target.getName ()); // Output: Alice System.out.println (target.get.get ()); // Output: 25 2. Properties conversion: Beanutils provides rich types of converters, which can automatically convert a variety of types of attribute values into target type without manually writing conversion logic. Example code: SourceBean source = new SourceBean(); source.setid ("1234"); // The attributes of type type TargetBean target = new TargetBean(); // Convert the attribute value of the source object to the target type to the target object BeanUtils.copyProperties(target, source); System.out.println (target.getid ()); // Output: 1234 (int type) 3. Attribute mapping: Beanutils also supports the attribute value of one JavaBean to another JavaBean according to the specified mapping relationship. Example code: SourceBean source = new SourceBean(); source.setUserName("Alice"); TargetBean target = new TargetBean(); // Map the username attribute of the source object to the name property of the Target object BeanUtils.copyProperty(target, "name", source, "userName"); System.out.println (target.getName ()); // Output: Alice Summarize: Commons Beanutils Core provides a simple and convenient way to operate the JavaBean object without manually writing a tedious code.By flexibly using the Java reflection mechanism and internal provincial mechanism, Beanutils realizes the functions of attribute copying, attribute value conversion, and attribute mapping, which greatly improves the maintenance of development efficiency and code.In daily development, we can use Beanutils to simplify JavaBean's operations according to specific needs.