找到一个参数构造函数，该参数可从参数类分配

//package com.nowjava;
/** 
 来自 时   代    Java - nowjava.com**/

import java.lang.reflect.Constructor;


public class Main {

    public static void main(String[] argv) throws Exception {

        Class clazz = String.class;

        Class parameter = String.class;

        System.out.println(findConstructor(clazz, parameter));

    }


    /**

     * Find one parameter constructor which parameter is

     * assignable from parameter class

     *

     * @param clazz class whose constructor we are finding

     * @param parameter parameter class

     * @return constructor

     */

    public static <T> Constructor<T> findConstructor(Class<T> clazz,

            Class parameter) {

        Constructor[] constructors = clazz.getDeclaredConstructors();


        for (Constructor constructor : constructors) {

            if (constructor.getParameterTypes().length == 1

                    && constructor.getParameterTypes()[0]

                            .isAssignableFrom(parameter))
                            /**
                            n o w j a v a . c o m 提供 
                            **/

                return constructor;

        }


        return null;

    }


    /**

     * Find constructor of class which has these parameters

     *

     * @param clazz class of constructor we are finding

     * @param parameters constructor parameters

     * @param <T> type of class

     * @return constructor or null if cannot be find

     */

    public static <T> Constructor<T> findConstructor(Class<T> clazz,

            Class[] parameters) {

        Constructor[] constructors = clazz.getConstructors();


        for (Constructor constructor : constructors) {

            if (constructor.getParameterTypes().length == parameters.length) {

                if (isAssignable(constructor.getParameterTypes(),

                        parameters))

                    return constructor;

            }

        }


        return null;

    }


    /**

     * Determine if classes can be assigned from

     *

     * @param c1 first array of classes

     * @param c2 second array of classes

     * @return true if c1 array can be assigned from c2 array

     */

    public static boolean isAssignable(