The technical principles of the Commons Beanutils framework in the Java class library
The technical principles of the Commons Beanutils framework in the Java class library
Commons Beanutils is a set of open source Java libraries provided by the Apache Software Foundation, which can simplify the copy and conversion operation of the attribute value between the Java objects.The framework is based on the Java reflection mechanism, providing developers with a convenient and flexible way to operate the attributes of the Java object.
Technical principle:
1. Reflective mechanism: Commons Beanutils obtains and sets the attribute values of the object by using the Java's reflection mechanism, without explicitly writing a large number of Getter and Setter methods.By reflecting, it can dynamically determine the attributes of the object during runtime, and realize the copying and conversion of the attribute value.
2. Based on the descriptor: Commons Beanutils framework is based on Java's Introspector and PropertyDescriptor to describe the attributes of the Java object.The descriptor contains information such as the name of the attribute, the Getter, and the Setter method. It can easily obtain and set the attribute value through the descriptor.
3. Type conversion: Commons Beanutils provides a flexible type of type conversion mechanism that can convert different types of attribute values and give it to the target object.It supports custom type converters, and developers can implement conversion rules between specific types according to their needs.
4. Processing of complex objects: Commons Beanutils can not only process basic data types, but also process complex Java objects, such as collection and nested objects.It can automatically copy and convey the attribute value between the source objects and the target object, which greatly simplifies the development work.
Example code:
1. Obtain object attribute value:
Person person = new Person();
person.setName("John Doe");
person.setAge(25);
String name = BeanUtils.getProperty(person, "name");
int age = Integer.parseInt(BeanUtils.getProperty(person, "age"));
System.out.println("Name: " + name);
System.out.println("Age: " + age);
2. Set object attribute value:
Person person = new Person();
BeanUtils.setProperty(person, "name", "John Doe");
BeanUtils.setProperty(person, "age", "25");
System.out.println("Name: " + person.getName());
System.out.println("Age: " + person.getAge());
3. Copy object attributes:
Person source = new Person();
source.setName("John Doe");
source.setAge(25);
Person destination = new Person();
BeanUtils.copyProperties(destination, source);
System.out.println("Name: " + destination.getName());
System.out.println("Age: " + destination.getAge());
Summarize:
The Commons Beanutils framework provides a convenient and flexible way to operate the attributes of the Java object by using the Java's reflection mechanism and descriptor.It simplifies the copy and conversion operation of the attribute value, enabling developers to handle the Java object more efficiently.
(Note: The above example code is for reference only. Please adjust according to the specific situation when actual use.)
