How to use Java reflex library in detail explanation

How to use Java reflex library in detail explanation Java reflection refers to information such as analyzing and operating attributes, methods and constructors during operation.It provides a powerful mechanism that can dynamically operate categories and objects at runtime and access members of them. The Java reflection library is a set of classes and interfaces provided by Java for processing reflexes.It contains in the Java.lang.reflet package and provides many APIs for obtaining and operating reflex information.Here are some commonly used reflex library usage methods. 1. Get the Class object Through the Java reflection, we can get a class Class object to obtain the detailed information of the class.You can use the following methods to obtain the Class object: // Get the Class object through the class name Class<?> clazz = Class.forName("com.example.MyClass"); // Get the Class object through the object Class<?> clazz = obj.getClass(); // Obtain the Class object through the class type constant Class<?> clazz = MyClass.class; 2. Get the attribute information of the class Once there is a Class object, we can get the attribute information of the class.You can use the following method to obtain the field of the class: // Get all public fields (including inheritance fields) Field[] fields = clazz.getFields(); // Get all fields (excluding inheritance fields) Field[] fields = clazz.getDeclaredFields(); // Get the field of specified name Field field = clazz.getField("fieldName"); 3. Method information for the class Similarly, you can use reflection to obtain the method information of the class.Here are some commonly used methods: // Get all public methods (including inheritance methods) Method[] methods = clazz.getMethods(); // Get all methods (excluding inheritance methods) Method[] methods = clazz.getDeclaredMethods(); // Get the method of specified name and parameter type Method method = clazz.getMethod("methodName", param1Type, param2Type); 4. Examination object Through reflection, we can dynamically instantiate an object of a class at runtime.Use the following methods to instantiated objects: // Use the parameter non -constructor instantiated object Object obj = clazz.newInstance(); // Use the constructor to instantiate the object Constructor<?> constructor = clazz.getConstructor(param1Type, param2Type); Object obj = constructor.newInstance(param1Value, param2Value); 5. Visit and operate members Use reflexes to access and operate attributes and methods.Here are some commonly used methods of operating members: // Set the field value of the object field.set(obj, value); // Get the field value of the object Object value = field.get(obj); // The method of calling the object method.invoke(obj, param1, param2); // The return value of the acquisition method Object result = method.invoke(obj, param1, param2); Through the above introduction, we understand some of the common methods of the Java reflection library and know how to use reflection to obtain and operate information.Reflection is very useful in some scenarios, such as in the fields of framework development, dynamic agency and testing.However, improper use of reflection may also lead to performance problems and safety hazards, so it should be used with caution.