获取Java加载器和类完整结构的方法分享

package Collections;
public class text1 {
    public static void main(String[] args) throws ClassNotFoundException {
        //获取系统类的加载器
        ClassLoader systemClassLoader = ClassLoader.getSystemClassLoader();
        System.out.println(systemClassLoader);
        //获取系统类加载器的父类加裁器-->扩展类加裁器
        ClassLoader parent = systemClassLoader.getParent();
        System.out.println(parent);
        //获取扩展类加载器的父类加裁器-->根加裁器(c/c++)
        ClassLoader parent1 = parent.getParent();
        System.out.println(parent1);
        //测试当前美是哪个加载器加裁的
        ClassLoader classLoader = Class.forName("Collections.text1").getClassLoader();
        System.out.println(classLoader);
        //测试JDK内置的类是谁加载的
        classLoader = Class.forName("java.lang.Object").getClassLoader();
        System.out.println(classLoader);
        //如何获得系统类加截哭可以加裁的路径
        System.out.println(System.getProperty("java.class.path"));
    }
}

Field、Method、Constructor、Superclass、Interface、Annotation

package Collections;

import java.lang.reflect.Field;

​​​​​​​public class text1 {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException {
        Class c1 = Class.forName("Collections.person");
        //获得类的名字
        System.out.println(c1.getName());
        //获得包名 +类名System.out.println(cl.getSimpleName()); //获得类名
        //获得类的属性
        System.out.println("===================================");
        Field[] fields = c1.getFields(); //只能找到public属性
        fields = c1.getDeclaredFields(); //我到全部的属性
        for (Field field : fields) {
            System.out.println(field);
        }
        System.out.println("===================================");
        //获得指定属性的值
        Field name = c1.getDeclaredField("name");
        System.out.println(name);
    }
}

package Collections;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;

​​​​​​​public class text1 {
    public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, NoSuchMethodException {
        Class c1 = Class.forName("Collections.person");
        Method[] methods = c1.getMethods(); //获得本类及其父类的全部public方法
        for (Method method : methods) {
            System.out.println("正常的:"+method);
        }
        methods = c1.getDeclaredMethods();//获得本类的所有方以
        for (Method method : methods) {
            System.out.println("getDeclaredMethods:"+method);
        }
        //获得指定方法
        //重载
        Method getName = c1.getMethod("getName", null) ;
        Method setName =c1.getMethod("setName", String.class) ;
        System.out.println(getName);System.out.println(setName);
        //获得指定的构造器
        System.out.println("===================================");
        Constructor[] constructors = c1.getConstructors();//获得public方法
        for (Constructor constructor : constructors) {
            System.out.println(constructor);
            constructors = c1.getDeclaredConstructors();//获得所有方法
            for (Constructor constructor1 : constructors) {
                System.out.println("#" + constructor1);
            }
        }
        //指定的某一个构造器
        Constructor declaredConstructors=c1.getDeclaredConstructor(String.class,int.class, String.class, String.class);
        System.out.println("指定的某一个构造器:"+declaredConstructors);
    }
}

package Collections;

public class person_text {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        //获得Class对象
        Class c1 = Class.forName("Collections.person");
        //构造一个对象
        person user = (person)c1.newInstance();
        //本质是调用了类的无参构造器
        System.out.println(user);
    }
}

package Collections;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class person_text {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, InvocationTargetException, NoSuchMethodException {
        //获得Class对象
        Class c1 = Class.forName("Collections.person");
        //通过构造器创建对象
        Constructor constructor = c1.getDeclaredConstructor(String.class, int.class,String.class, String.class);
        person user2 = (person)constructor.newInstance("Lisa",19,"女","北京");
        System.out.println(user2);
    }
}