package com.lkb.autoCode.util;

import com.lkb.autoCode.constant.AutoCodeConstant;

import java.io.File;

import java.io.FileInputStream;

import java.io.InputStream;

/**

 * DynamicClassLoader 动态类加载器

 *

 * @author Lilin

 * @date 2016/5/23

 */

public class DynamicClassLoader extends ClassLoader {

    private String classPath;

    public DynamicClassLoader(String classPath, ClassLoader parent) {

        super(parent);

        this.classPath = classPath;

    }

    @Override

    public Class<?> loadClass(String name) throws ClassNotFoundException {

        // 判断当前加载的类是否是需要动态重新加载的类，

        // 假如是通过重写的findClass在自定义的ClassLoader里面加载，

        // 假如不是就调用父ClassLoader默认加载

        if (name != null && name.equals(classPath)) {

            return findClass(name);

        }

        return super.loadClass(name, false);

    }

    /**

     * 根据类名查找class

     *

     * @param fullClassPath 类全路径（包）

     * @return

     * @throws ClassNotFoundException

     */

    @Override

    protected Class<?> findClass(String fullClassPath)

            throws ClassNotFoundException {

        byte[] raw = readClassBytes(fullClassPath);

        // definClass方法参数说明：name：类包的全路径如com.lkb.sb.client.shanghaiC.ShangHaiLoginClient

        //                         b：读取的class文件的byte数组

        //                         off：从byte数组中读取的索引

        //                         len：从byte数组中读取的长度

        // 注：假如此类中有引入别的class类，如com.lkb.sb.client.BaseClient，循环执行findClass方法

        Class<?> clazz = defineClass(fullClassPath, raw, 0, raw.length);

        // 连接class

        resolveClass(clazz);

        return clazz;

    }

    /**

     * 读取class

     *

     * @param fullClassPath

     * @return

     */

    private byte[] readClassBytes(String fullClassPath) {

        byte[] raw = null;

        InputStream stream = null;

        try {

            File file = new File(AutoCodeConstant.BASE_PATH + fullClassPath.replaceAll("\\.", "/") + AutoCodeConstant.CLASS_SUFFIX);

            stream = new FileInputStream(file);

            raw = new byte[(int) file.length()];

            stream.read(raw);

        } catch (Exception e) {

        } finally {

            try {

                stream.close();

            } catch (Exception e) {

            }

        }

        return raw;

    }

}

                // 通过自定义类加载器来加载

                // 获取类的完成路径

                String fullClassPath = getFullClassPath(AutoCodeConstant.CLIENT_PACKAGE, provinceCode, cityCode, AutoCodeConstant.LOGIN_CLIENT);

                // 父ClassLoader设为当前线程的ClassLoader，试过使用ClassLoader.getSystemClassLoader(),发现获取的是系统级的，懒加载的类找不到

                dynamicClassLoader = new DynamicClassLoader(fullClassPath, Thread.currentThread().getContextClassLoader());

                loginInterface = (LoginInterface) dynamicClassLoader.loadClass(fullClassPath).getConstructor(new Class[]{CommonLoginSb.class, SbDefultModel.class}).newInstance(new Object[]{commonLoginSb, sbDefultModel});

                // 执行start方法

                resOutput = loginInterface.start(commonLoginSb.getMethod());