How to use a reflex library in the Java library

How to use a reflex library in the Java library Overview: Reflection is a powerful and flexible characteristic in the Java language. It allows the program to check and operate other types of methods, fields and constructors during runtime.Through reflection, we can dynamically load and execute the code when compiling do not know the specific class name and method name.In Java, the reflection mechanism is widely used in areas such as various frameworks, plug -in development, and testing frameworks.This article will introduce you how to use a reflex library in the Java library. 1. Get the class Class object: Before using reflexes, we first need to obtain the Class object to be operated.In Java, we can obtain the class Class object through the class name plus the .class keyword, as shown below: Class<?> myClass = MyClass.class; 2. Method of obtaining class: The method of obtaining a class is common operations in reflection.In Java, we can use the following methods to obtain a public method: -`getMethods ()`: All public methods to obtain a class, including the method of inheriting the parent class. -` GetDeclaredMethods () `: All methods to obtain a class declaration, including private methods. The following is an example code for obtaining a class and printing method name: Method[] methods = myClass.getMethods(); for (Method method : methods) { System.out.println("Method Name: " + method.getName()); } 3. The method of calling the class: Through reflection, we can call the class when runtime.The following is an example code of a dynamic call class method: Method method = myClass.getMethod("methodName", parameterTypes); Object result = method.invoke(myObject, methodArguments); In the above code, we use the `GetMethod` method to obtain the reflex object of the method, and then use the` Invoke` method to call the method to pass the instance object and method parameters.Finally, we can get the return value of the method in the `Result`. 4. Obtain and set the field field: Reflex can also be used for dynamic operations fields.The following is an example code for the field value of obtaining and setting classes: Field field = myClass.getDeclaredField("fieldName"); field.setAccessible(true); // Get the field value Object value = field.get(myObject); // Set the field value field.set(myObject, newValue); In the above code, we first use the `GetDeclaredField` method to obtain the reflected object of the field, and then use the accessability of the field to set the field with the` setccessible (true) `.You can obtain the value of the field through the `Field.get` method, and the value of the field can be set through the` Field.set` method. 5. Create an instance: Reflex can also be used to create instances dynamically at runtime.The following is an instantiated example code: Constructor<?> constructor = myClass.getConstructor(parameterTypes); Object myObject = constructor.newInstance(constructorArguments); In the above code, we use the `GetConStructor` method to obtain the reflected object of the constructor, and then use the` newInstance` method to create an instance of the class to pass the parameters of the constructor. Summarize: Through the reflection mechanism, we can dynamically obtain and call class methods, operating fields, and instances of creation in the Java library.Although the reflection provides strong flexibility, it also needs to pay attention to the performance problems it may be introduced.Therefore, when using reflexes, weighing the choice of flexibility and performance to avoid abuse of reflection. I hope this article can help you understand how to use a reflection library in the Java library.Through reflection, you can operate and control code more flexibly, bringing more possibilities to various complex scenarios.Start trying to use reflexes and play its advantages in actual development!