Analysis of the reflection tool method commonly used in the Java class library

Analysis of the reflection tool method commonly used in the Java class library Reflection is a powerful feature of Java. It allows us to dynamically check, modify and call class methods, fields, and constructors at runtime.Java's reflection tool method provides developers with flexibility and strong control capabilities. This article will introduce the reflection tools commonly used in the Java class library, including obtaining Class objects, access fields, calling methods, and creating instances. 1. Get the Class object In the Java reflection, we first need to obtain the Class object of the reflected object.You can use the following method to obtain the Class object: Class Clazz = myclass.class; // Get it through the class name Class clazz = obj.getclass (); // Get it through objects Class Clazz = class.Forname ("com.example.myclass"); // Obtain it through the full -limited name of the class 2. Access field Reflex allows us to access and set the fields of the objects at runtime.You can use the following methods to obtain and set the value of the field: Field filed = Clazz.getField ("Fieldname"); // Get the public field Field filed = Clazz.getDeclaredfield ("" Fieldname "); // Get all fields Field.setaccessible (true); // Set access to private fields Object value = field.get (obj); // Get the value of the field field.set (obj, value); // Set the value of the field 3. Calling method The reflection can also call the object at runtime.You can use the following method to call the method: Method method = Clazz.getMethod ("MethodName", Param1.Class, Param2.class); // Get the public method Method method = Clazz.getDeClaredMethod ("MethodName", param1.class, param2.class); // Get all methods Method.setaccessible (true); // Set access to private methods Object result = method.invoke (obj, arg1, arg2); // call method and get the return value 4. Create instance The reflection also provides the ability to create object instances.You can use the following methods to create objects: Constructor <?> Constructionor = Clazz.getConStructor (Param1.Class, Param2.class); // Get the participation method method Constructor <?> Constructionor = Clazz.getDeClaredConStructor (); // Get the parameter non -constructor method Constructor.Setac sense (true); // Set access to private construction methods Object instance = constructor.newinstance (ARG1, ARG2); // Create an object instance By using these commonly used reflection tool methods, we can dynamically obtain and operate information about the operation at runtime, making our code more flexible and scalable. When using reflexes, you need to pay attention to the low performance of the reflection, so you should use it with caution.At the same time, the use of reflection tools reasonably can help us solve some complex problems in specific scenarios. In short, the reflex tool method commonly used in the Java library provides developers with a powerful ability, which can dynamically view, modify and call class methods, fields, and constructor functions at runtime.By using these tools reasonably, our code can make our code more flexible and intelligent.