Obtener funciones:
1. 获取成员变量们
* Field[] getFields() :获取所有public修饰的成员变量
* Field getField(String name) 获取指定名称的 public修饰的成员变量
* Field[] getDeclaredFields() 获取所有的成员变量,不考虑修饰符
* Field getDeclaredField(String name)
2. 获取构造方法们
* Constructor<?>[] getConstructors()
* Constructor<T> getConstructor(类<?>... parameterTypes)
* Constructor<T> getDeclaredConstructor(类<?>... parameterTypes)
* Constructor<?>[] getDeclaredConstructors()
3. 获取成员方法们:
* Method[] getMethods()
* Method getMethod(String name, 类<?>... parameterTypes)
* Method[] getDeclaredMethods()
* Method getDeclaredMethod(String name, 类<?>... parameterTypes)
4. 获取全类名
* String getName()
Campo:
operación de variable miembro :
1. 设置值
* void set(Object obj, Object value)
2. 获取值
* get(Object obj)
3. 忽略访问权限修饰符的安全检查
* setAccessible(true):暴力反射
Ejemplo:
crear una persona de clase simple
public class Person {
private String name;
private int age;
public String a;
protected String b;
String c;
private String d;
public Person() {
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
", a='" + a + '\'' +
", b='" + b + '\'' +
", c='" + c + '\'' +
", d='" + d + '\'' +
'}';
}
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public void eat(){
System.out.println("eat...");
}
public void eat(String food){
System.out.println("eat..." + food);
}
}
public class ReflectDemo02 {
public static void main(String[] args) throws Exception {
//0获取Personde Class对象
Class personClass = Person.class;
/*
1. 获取成员变量们
* Field[] getFields() :获取所有public修饰的成员变量
* Field getField(String name) 获取指定名称的 public修饰的成员变量
* Field[] getDeclaredFields() 获取所有的成员变量,不考虑修饰符
* Field getDeclaredField(String name)
*/
//Field[] getFields() :获取所有public修饰的成员变量
Field[] fields = personClass.getFields();
for (Field field : fields) {
System.out.println(field);
}
System.out.println("--------------------------");
//Field getField(String name) 获取指定名称的 public修饰的成员变量
Field a = personClass.getField("a");
//获取成员变量a的值
Person p = new Person();
Object result = a.get(p);
System.out.println(result);
//设置a的值
a.set(p,"张三");
System.out.println(p);
System.out.println("===================");
//Field[] getDeclaredFields() 获取所有的成员变量,不考虑修饰符
Field[] declaredFields = personClass.getDeclaredFields();
for (Field declaredField : declaredFields) {
System.out.println(declaredField);
}
//Field getDeclaredField(String name)
Field d = personClass.getDeclaredField("d");
//忽略访问权限修饰符的安全检查
d.setAccessible(true);//暴力反射
Object value2 = d.get(p);
System.out.println(value2);
}
}
Demostración del programa:
Constructor: método de construcción
Crear objeto:
T newInstance (Object ... initargs)
* 如果使用空参数构造方法创建对象,操作可以简化:
* Class对象的newInstance方法
Ejemplo:
public class ReflectDemo03 {
public static void main(String[] args) throws Exception {
//0获取Personde Class对象
Class personClass = Person.class;
/*
2. 获取构造方法们
* Constructor<?>[] getConstructors()
* Constructor<T> getConstructor(类<?>... parameterTypes)
* Constructor<T> getDeclaredConstructor(类<?>... parameterTypes)
* Constructor<?>[] getDeclaredConstructors()
*/
//Constructor<T> getConstructor(类<?>...parameterTypes)
Constructor constructor = personClass.getConstructor(String.class, int.class);
System.out.println(constructor);
//创建对象
Object person = constructor.newInstance("张三", 22);
System.out.println(person);
System.out.println("----------------");
Constructor constructor1 = personClass.getConstructor(String.class, int.class);
System.out.println(constructor1);
//创建对象
Object o = personClass.newInstance();
System.out.println(o);
}
}
Demostración del programa:
Método: Objeto de
método Método de ejecución:
Invocación de objeto (Objeto obj, Objeto ... args)
* 获取方法名称:
* String getName:获取方法名
Obtenga el nombre completo de la clase
* String getName ()
Ejemplo:
public class ReflectDemo04 {
public static void main(String[] args) throws Exception {
//0获取Personde Class对象
Class personClass = Person.class;
/*
3. 获取成员方法们:
* Method[] getMethods()
* Method getMethod(String name, 类<?>... parameterTypes)
* Method[] getDeclaredMethods()
* Method getDeclaredMethod(String name, 类<?>... parameterTypes)
*/
//获取指定名称的方法
Method eat_meath = personClass.getMethod("eat");
Person p = new Person();
//执行方法
eat_meath.invoke(p);
Method eat_method2 = personClass.getMethod("eat", String.class);
//执行方法
eat_method2.invoke(p,"饭");
//获取所有public 修饰的方法
Method[] methods = personClass.getMethods();
for (Method method : methods) {
System.out.println(method);
String name = method.getName();
System.out.println(name);
//method.setAccessible(true);
}
//获取类名
String className = personClass.getName();
System.out.println(className);//domain.Person
}
}
Demostración del programa: