import org.junit.Test;
public class ClassDemo {
@Test
public void test() throws ClassNotFoundException {
//（1）类型名.class
Class clazz = Person.class;
//（2）对象.getClass()
Person p = new Person();
Class clazz2 = p.getClass();
//（3）Class.forName(类型全名称)
//全类名 ：包含包名在内的类的全名称
Class clazz3 = Class.forName("com.atguigu.java2.Person");
//（4）ClassLoader的类加载器对象.loadClass(类型全名称)
ClassLoader classLoader = this.getClass().getClassLoader();
Class clazz4 = classLoader.loadClass("com.atguigu.java2.Person");
System.out.println(clazz == clazz2 && clazz3 == clazz4 && clazz == clazz3);
}
}
import org.junit.Test;
import java.lang.annotation.Annotation;
import java.lang.reflect.*;
import java.util.Arrays;
public class ClassDemo2 {
@Test
public void test(){
//1.获取Class对象
Class clazz = Student.class;
//2.获取方法-本类及父类中所有public修饰的方法
Method[] methods = clazz.getMethods();
//3.遍历
for (Method method : methods) {
System.out.println(method);
}
System.out.println("=================================");
//获取本类中所有的方法
Method[] declaredMethods = clazz.getDeclaredMethods();
for (Method declaredMethod : declaredMethods) {
System.out.println(declaredMethod);
}
}
@Test
public void test2() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
Student s = new Student();
//1.获取Class对象
Class clazz = Student.class;
//2.获取指定的方法--只能获取public修饰的方法
Method method = clazz.getMethod("studentPublicDemo", String.class);
//3.调用方法
method.invoke(s,"aaa");
}
@Test
public void test3() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
Student s = new Student();
//1.获取Class对象
Class clazz = Student.class;
//2.调用指定方法---可以获取任意权限修饰符修饰的方法
Method studentPrivateSay = clazz.getDeclaredMethod("studentPrivateSay",int.class);
//3.允许访问--授权
studentPrivateSay.setAccessible(true);
//4.调用方法
studentPrivateSay.invoke(s,1001);
}
@Test
public void test4(){
//1.获取Class对象
Class clazz = Student.class;
//2.获取属性--获取本类及父类中public修饰的属性
Field[] fields = clazz.getFields();
for (Field field : fields) {
System.out.println(field);
}
System.out.println("=============================================");
//获取属性-获取本类中所有的属性
Field[] declaredFields = clazz.getDeclaredFields();
for (Field declaredField : declaredFields) {
System.out.println(declaredField);
}
}
@Test
public void test5() throws NoSuchFieldException, IllegalAccessException {
Student s = new Student();
//1.获取Class对象
Class clazz = Student.class;
//2.获取指定的属性---获取public修饰的属性
Field studentPublicName = clazz.getField("studentPublicName");
//3.给属性赋值
studentPublicName.set(s,"longge");
s.show();
}
@Test
public void test6() throws NoSuchFieldException, IllegalAccessException {
Student s = new Student();
//1.获取Class对象
Class clazz = Student.class;
//2.获取指定的属性-任意权限修饰符修饰的属性都可以
Field studentPrivateId = clazz.getDeclaredField("studentPrivateId");
//3.允许访问
studentPrivateId.setAccessible(true);
//4.给属性赋值
studentPrivateId.setInt(s,1001);
s.show();
}
@Test
public void test7() throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
//1.获取Class对象
Class clazz = Employee.class;
//2.获取指定的构造器
//Constructor constructor = clazz.getConstructor();
//3.创建对象
//Employee e = (Employee) constructor.newInstance();
//e.show();
//注意：如果要通过空参构造器创建对象可以直接使用Class的对象调用newInstance方法
clazz.newInstance();
}
@Test
public void test8(){
//1.获取Class对象
Class clazz = Student.class;
//2.获取父类的运行时类
Class superclass = clazz.getSuperclass();
}
@Test
public void test9() throws NoSuchMethodException {
//1.获取Class的对象
Class clazz = Employee.class;
//2.获取注解--获取类上的注解
Annotation[] annotations = clazz.getAnnotations();
for (Annotation annotation : annotations) {
System.out.println(annotation);
}
System.out.println("=====================================");
//3.获取指定结构上的注意：①先获取那个结构 ②再获取上面的注解
//获取方法
Method show = clazz.getMethod("show");
//获取方法上的注解
Annotation[] annotations1 = show.getAnnotations();
for (Annotation annotation : annotations1) {
System.out.println(annotation);
}
}
@Test
public void test10(){
//1.获取Class对象
Class clazz = Student.class;
//2.获取本类中所有的属性
Field[] declaredFields = clazz.getDeclaredFields();
for (Field declaredField : declaredFields) {
//获取注解
declaredField.getAnnotations();
//获取属性的权限修饰符
int modifiers = declaredField.getModifiers();
//通过Modifier的toString方法将数字转成对应的名字
System.out.print(Modifier.toString(modifiers) + " ");
//获取属性的类型
Class type = declaredField.getType();
System.out.print(type + " ");
//获取属性的名字
System.out.print(declaredField.getName() + ";");
System.out.println();
}
}
@Test
public void test11(){
//1.获取Class的对象
Class clazz = Student.class;
//2.获取本类中所有方法
Method[] declaredMethods = clazz.getDeclaredMethods();
for (Method declaredMethod : declaredMethods) {
//获取方法的权限修饰符
System.out.print(Modifier.toString(declaredMethod.getModifiers()) + " ");
//获取方法的返回值类型
System.out.print(declaredMethod.getReturnType() + " ");
//获取方法的名字
System.out.print(declaredMethod.getName() + " ");
//获取方法的形参的类型
System.out.print("(");
Class[] classes = declaredMethod.getParameterTypes();
System.out.print(Arrays.toString(classes));
System.out.print(")");
System.out.println();
}
}
}
