In -depth understanding of the Reflext Framework API technology in the Java class library

In -depth understanding of the Reflext Framework API technology in the Java class library introduction: In Java programming, we often need to dynamically access and operate the attributes, methods, and constructors of the operating object.Java reflection provides such capabilities, which can obtain and operate information such as class, interfaces, methods, fields, etc. at runtime, so that the program can run and expand more flexible and dynamically.Java's reflection technology usually uses Reflext Framework API to achieve. What is reflex technology? Reflection refers to the dynamic information that is dynamically obtained and used during runtime, without the need to know the structure of the class in advance.Through Java's reflection technology, we can check the methods and fields of the class during the running period, and can dynamically create objects, call methods, acquisition and setting attributes, etc. Reflext Framework API in the Java Class Library Java's reflection technology is implemented through the class and interfaces in the java.lang.reflet package. The following are some commonly used classes and interfaces: 1. Class class: It represents a class or interface that can obtain class information at runtime, such as class names, parent class, implementation interfaces, methods, fields, etc.You can use the static method of the Class class to obtain a class class object. Example code: Class <student> StudentClass = Student.class; // Get the class object of the Student class 2. Constructionor class: The constructor of the representative class can obtain information such as parameter type, modifiers and other information of the constructor when runtime.You can use the GetConStructors () method of class class to obtain all the constructors of a class. Example code: Constructor <strongnt> constructor = StudentClass.GetDeCladConStructor (String.class, Int.class); // The constructor with the Student class with the Student and int parameter constructor 3. Method class: Representative class methods, you can obtain information such as the return type, parameter type, modifier and other information of the method during runtime.You can use the GetMethods () method of class class to obtain all methods of a class. Example code: METHOD METHOD = StudentClass.getDeClaredMethod ("GetName"); // Get the getName method of the Student class 4. Field class: The field of the representative class can obtain information such as the type, modifiers and other information of the field at runtime.You can use the GetFields () method of class class to obtain all fields of a class. Example code: Field Field = StudentClass.getDeClaredfield ("name"); // Get the name field of the Student class class Through the above classes and interfaces, we can obtain category information at runtime and can dynamically create objects, call methods, obtain and setting attributes, etc. Application scenario: Java reflection technology has a wide range of applications in many scenarios. The following are several common application scenarios: 1. Dynamic proxy: Using the reflection mechanism, you can dynamically generate an agent class during runtime. When realizing dynamic proxy, you need to use reflex -related classes and interfaces. 2. Framework development: Many development frameworks, such as Spring and Hibernate, use reflex technology to achieve the flexibility and scalability of the program. 3. Unit test: When testing, you can use reflex technology to access private methods and fields to simplify the test code. Summarize: Through the Reflext Framework API in the Java Library, we can implement dynamic operations and access to the class, so that the program can run and expand more flexible and dynamically.Reflex technology is widely used in Java programming, and developers can flexibly use these APIs to achieve various functions according to specific needs.