Anatomy of Java Reflection Main method

The previous article reflected the member method of the class, and the main method should also be included, because the main method is a static method.

But the actual Mian reflection is slightly different, the reason is mainly to maintain 1.5 compatible 1.4 version during the upgrade process: reasoning as follows

1. The parameter of the main method is a parameter of type string[]

2, 1.5 support variable parameters, so it can be variable parameter form to read the parameters,

such as: Main (string[]{"Arg1", "Arg2"}) ===>

Main ("Arg1", "arg2")

3, but in 1.4, does not support variable parameters, so will not be decomposed, directly as the main (string[]{"Arg1", "AREG2"})

4, for compatibility with 1.4 version, the main method is still only receive a parameter type string[] parameter

Combine the above:

When you pass in the string["arg0", "arg1", the 1.5 version will be resolved to: Two parameter values are "arg0", "arg1" parameters

A parameter that only receives a string[] type with the main method does not conform.

There are two ways to handle this:

1. Pass in an array and put string[] in the array: New object[]{new string[]{"Arg1", "Arg2"}}

2. Convert an array to an object

The test generation file is as follows:

Mian Method:

1  Package Cn.rt.gwq; 2 3  Public class maintest {4     5      Public Static void Main (string[] args) {6         System.out.println ("Main run ..."); 7     }89 }

Demo test Method:

1  PackageCn.rt.gwq;2 3 ImportJava.lang.reflect.Method;4 5  Public classDemo_mainrflt {6 7      Public voidTest ()throwsexception{8         9Class clazz = Class.forName ("Cn.rt.gwq.mainTest");Tenmethod = Clazz.getmethod ("main", string[].class); One         //method One: Put an array inside the array AMethod.invoke (NULL,Newobject[]{Newstring[]{"arg0", "Arg1"}}); -         //method Two: Cast the array into object -Method.invoke (NULL, (Object)Newobject[]{"arg0", "Arg1"}); the          -     } -      -}

Anatomy of Java Reflection Main method