Class.formName 和 ClassLoader 类加载的区别

Posted 2020-11-27 wanjun-top

User.java

public class User {
    private static int a = 10;
    {
        System.out.println("普通代码块..");
    }
    static {
        System.out.println("静态变量" + a);
        System.out.println("静态代码块..");
    }
}

TestClassLoad.java

public class TestClassLoad {
    public static void main(String[] args) throws ClassNotFoundException {
        ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
        Class<?> loadUser = systemClassLoader.loadClass("User");
        String name = loadUser.getName();
        System.out.println(name);
        System.out.println("-------------------");

        Class<?> forName = Class.forName("User");
        String name2 = forName.getName();
        System.out.println(name2);
    }
}

 

运行结果：

User
-------------------
静态变量10
静态代码块..
User

说明：区别在于，通过 Class.forName 加载类会 执行 静态方法。