实例讲解Java基础之反射

public class Phone implements List {  public double price;  public String name;  public Phone() {  }  public Phone(double price, String name) {    this.price = price;    this.name = name;  }  public double getPrice() {    return price;  }  public void gege(String h){    System.out.println("gege的"+h);  }  public void setPrice(double price) {    this.price = price;  }  public String getName() {    return name;  }  public void setName(String name) {    this.name = name;  }  @Override  public String toString() {    return "Phone{" +        "price=" + price +        ", name='" + name + '/'' +        '}';  }  @Override  public int size() {    return 0;  }  @Override  public boolean isEmpty() {    return false;  }  @Override  public boolean contains(Object o) {    return false;  }  @Override  public Iterator iterator() {    return null;  }  @Override  public Object[] toArray() {    return new Object[0];  }  @Override  public boolean add(Object o) {    return false;  }  @Override  public boolean remove(Object o) {    return false;  }  @Override  public boolean addAll(Collection c) {    return false;  }  @Override  public boolean addAll(int index, Collection c) {    return false;  }  @Override  public void clear() {  }  @Override  public Object get(int index) {    return null;  }  @Override  public Object set(int index, Object element) {    return null;  }  @Override  public void add(int index, Object element) {  }  @Override  public Object remove(int index) {    return null;  }  @Override  public int indexOf(Object o) {    return 0;  }  @Override  public int lastIndexOf(Object o) {    return 0;  }  @Override  public ListIterator listIterator() {    return null;  }  @Override  public ListIterator listIterator(int index) {    return null;  }  @Override  public List subList(int fromIndex, int toIndex) {    return null;  }  @Override  public boolean retainAll(Collection c) {    return false;  }  @Override  public boolean removeAll(Collection c) {    return false;  }  @Override  public boolean containsAll(Collection c) {    return false;  }  @Override  public Object[] toArray(Object[] a) {    return new Object[0];  }}

public class Test2 {  public static void main(String[] args) throws IllegalAccessException, InstantiationException, ClassNotFoundException {    //第一种    Phone p = new Phone(2999,"小米");    System.out.println(p);//Phone{price=2999.0, name='小米'}    //第二种 需要一个空参构造    Class<Phone> phoneClass = Phone.class;    Phone phone = phoneClass.newInstance();    phone.setName("华为");    phone.setPrice(3499);    System.out.println(phone);//Phone{price=3499.0, name='华为'}    //第三种    Class<?> aclass = Class.forName("com.demo.bean.Phone");    Phone p2 = (Phone) aclass.newInstance();    p2.setPrice(2999);    p2.setName("魅族");    System.out.println(p2);//Phone{price=2999.0, name='魅族'}    //第四种,需要一个配置文件phone.properties    String name = ResourceBundle.getBundle("phone").getString("myphone");    Class<?> bClass = Class.forName(name);    Phone p3 = (Phone) bClass.newInstance();    p3.setPrice(3299);    p3.setName("锤子");    System.out.println(p3);//Phone{price=3299.0, name='锤子'}  }}

public class Test3 {  public static void main(String[] args) throws ClassNotFoundException {    String string = ResourceBundle.getBundle("phone").getString("myphone");    Class<?> aClass = Class.forName(string);    //获取类的完整路径    System.out.println(aClass.getName());//com.demo.bean.Phone    //获取类的简单名字    System.out.println(aClass.getSimpleName());//Phone    //获取类的父类    Class<?> superclass = aClass.getSuperclass();    System.out.println(superclass.getName());//java.lang.Object    System.out.println(superclass.getSimpleName());//Object    //获得类的接口    Class<?>[] interfaces = aClass.getInterfaces();    for (Class<?> in:interfaces       ) {      System.out.println(in.getSimpleName());    }  }}

public class Test4 {  public static void main(String[] args) throws ClassNotFoundException, IllegalAccessException, InstantiationException, NoSuchMethodException {    String string = ResourceBundle.getBundle("phone").getString("myphone");    Class<?> aClass = Class.forName(string);    //调用的是无参的构造方法    Phone p1 = (Phone) aClass.newInstance();    p1.setName("华为");    p1.setPrice(2999);//Phone{price=2999.0, name='华为'}    System.out.println(p1);    //获得无参的构造方法    Constructor<?> constructor = aClass.getConstructor();    System.out.println(constructor);//public com.demo.bean.Phone()    //获得所有的构造方法    Constructor<?>[] constructors = aClass.getConstructors();    for (Constructor<?> c:constructors       ) {      System.out.println(c);    }  }}

public class Test5 {  public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException,InstantiationException,IllegalAccessException,InvocationTargetException{    String string = ResourceBundle.getBundle("phone").getString("myphone");    Class<?> aClass = Class.forName(string);    //包含了父类的方法    Method[] methods = aClass.getMethods();    for (Method m:methods       ) {      System.out.println(m);    }    //本类中的方法，没有父类的方法    Method[] declaredMethods = aClass.getDeclaredMethods();    for (Method m:declaredMethods       ) {      System.out.println(m);    }    Method gege = aClass.getMethod("gege",String.class);    //获取gege方法的权限修饰符    System.out.println(Modifier.toString(gege.getModifiers()));    //获取gege方法的返回值类型    System.out.println(gege.getReturnType());    //设置gege的参数值    Object o = aClass.newInstance();    gege.invoke(o,"aa");  }}

public class Test6 {  public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException, InstantiationException {    String string = ResourceBundle.getBundle("phone").getString("myphone");    Class<?> aClass = Class.forName(string);    //只能调用public 字段,但是能得到父类的字段    Field[] fields = aClass.getFields();    for (Field f:fields       ) {      System.out.println(f.getName());    }    //只能调用public 字段，只能得到本类中的字段    Field[] declaredFields = aClass.getDeclaredFields();    for (Field f:declaredFields       ) {      System.out.println(f.getName());    }    //获取某一字段的数据类型    Field name = aClass.getField("name");    String simpleName = name.getType().getSimpleName();    System.out.println(simpleName);    name.setAccessible(true);    Object o = aClass.newInstance();    name.set(o,"华为");    System.out.println(name.get(o));  }}