Java Reflection教程(3):Constructor构造函数

通过Class的getConstructors 可以取得类的所有构造函数定义。

[java] Class aClass = ...//obtain class object
Constructor[] constructors = aClass.getConstructors();
Class aClass = ...//obtain class object
Constructor[] constructors = aClass.getConstructors();

如果知道构造函数的参数定义，可以直接取得对应的构造函数，如：

[java]
Class aClass = ...//obtain class object
Constructor constructor =
aClass.getConstructor(new Class[]{String.class});
Class aClass = ...//obtain class object
Constructor constructor =
aClass.getConstructor(new Class[]{String.class});

如果Reflection API找不到对应的构造函数，则抛出NoSuchMethodException异常。

1. 获取构造函数的参数定义

[java]
Class[] parameterTypes = constructor.getParameterTypes();
Class[] parameterTypes = constructor.getParameterTypes();

2. 使用构造函数定义创建实例

[java]
//get constructor that takes a String as argument
Constructor constructor = MyObject.class.getConstructor(String.class);

MyObject myObject = (MyObject)
constructor.newInstance("constructor-arg1");
//get constructor that takes a String as argument
Constructor constructor = MyObject.class.getConstructor(String.class);

MyObject myObject = (MyObject)
constructor.newInstance("constructor-arg1");

newInstance 的参数可以选，调用时参数个数必须和对应的Constructor 定义的参数个数一致。

摘自 引路蜂移动软件