你的意思是类的名字都不知道吗？javadoc中说得很明白，还有疑问可以去查查getConstructor
public Constructor getConstructor(Class[] parameterTypes)
throws NoSuchMethodException,
SecurityException
Returns a Constructor object that reflects the specified public constructor of the class represented by this Class object. The parameterTypes parameter is an array of Class objects that identify the constructor's formal parameter types, in declared order.
The constructor to reflect is the public constructor of the class represented by this Class object whose formal parameter types match those specified by parameterTypes. If there is a security manager, this method first calls the security manager's checkMemberAccess method with this and Member.PUBLIC as its arguments. If the class is in a package, then this method also calls the security manager's checkPackageAccess method with the package name as its argument. Either of these calls could result in a SecurityException.invoke
public Object invoke(Object obj,
Object[] args)
throws IllegalAccessException,
IllegalArgumentException,
InvocationTargetException
Invokes the underlying method represented by this Method object, on the specified object with the specified parameters. Individual parameters are automatically unwrapped to match primitive formal parameters, and both primitive and reference parameters are subject to method invocation conversions as necessary.
If the underlying method is static, then the specified obj argument is ignored. It may be null. If the number of formal parameters required by the underlying method is 0, the supplied args array may be of length 0 or null. If the underlying method is an instance method, it is invoked using dynamic method lookup as documented in The Java Language Specification, Second Edition, section 15.12.4.4; in particular, overriding based on the runtime type of the target object will occur. If the underlying method is static, the class that declared the method is initialized if it has not already been initialized. If the method completes normally, the value it returns is returned to the caller of invoke; if the value has a primitive type, it is first appropriately wrapped in an object. If the underlying method return type is void, the invocation returns null.
public Constructor getConstructor(Class[] parameterTypes)
throws NoSuchMethodException,
SecurityException
Returns a Constructor object that reflects the specified public constructor of the class represented by this Class object. The parameterTypes parameter is an array of Class objects that identify the constructor's formal parameter types, in declared order.
The constructor to reflect is the public constructor of the class represented by this Class object whose formal parameter types match those specified by parameterTypes. If there is a security manager, this method first calls the security manager's checkMemberAccess method with this and Member.PUBLIC as its arguments. If the class is in a package, then this method also calls the security manager's checkPackageAccess method with the package name as its argument. Either of these calls could result in a SecurityException.invoke
public Object invoke(Object obj,
Object[] args)
throws IllegalAccessException,
IllegalArgumentException,
InvocationTargetException
Invokes the underlying method represented by this Method object, on the specified object with the specified parameters. Individual parameters are automatically unwrapped to match primitive formal parameters, and both primitive and reference parameters are subject to method invocation conversions as necessary.
If the underlying method is static, then the specified obj argument is ignored. It may be null. If the number of formal parameters required by the underlying method is 0, the supplied args array may be of length 0 or null. If the underlying method is an instance method, it is invoked using dynamic method lookup as documented in The Java Language Specification, Second Edition, section 15.12.4.4; in particular, overriding based on the runtime type of the target object will occur. If the underlying method is static, the class that declared the method is initialized if it has not already been initialized. If the method completes normally, the value it returns is returned to the caller of invoke; if the value has a primitive type, it is first appropriately wrapped in an object. If the underlying method return type is void, the invocation returns null.
class A
{
public A()
{}
public A(String str)
{}
}如果有参数是第二个