Java reflection case (don’t miss it)

The following is a Java reflection case introduced by the java learning tutorial column. I hope it will be helpful to friends in need!

Java reflection case

Requirements

Write a "framework" that cannot change any code of this class Under the premise, we can help us create objects of any class and execute any method

Use

Configuration file

Reflection

Steps

Define the full class name of the object to be created and the method to be executed in the configuration file

Load and read the configuration file in the program

Use reflection technology to load class files into memory

Create object

Execution method

Configuration file

className=Student
methodName=sleep

code

import java.io.InputStream;
import java.lang.reflect.Method;
import java.util.Properties;
/**
 * @author tanglei
 * @date 2020/6/11 3:10 下午
 */
public class ReflectTest {
    public static void main(String[] args) throws Exception {
        Student s = new Student();
        Properties pro = new Properties();
        //获取配置文件的路径
        ClassLoader classLoader = ReflectTest.class.getClassLoader();
        InputStream is = classLoader.getResourceAsStream("pro.properties");
        pro.load(is);
        String className = pro.getProperty("className");
        String methodName = pro.getProperty("methodName");
        //加载类进内存
        Class cla = Class.forName(className);
        Object obj = cla.newInstance();
        //加载方法进内存
        Method method = cla.getMethod(methodName);
        method.invoke(obj);
    }
}

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