java动态加载插件化编程详解

/**
 * Created by shengjk1 on 2017/12/11
 */
public class PluginManager {
  private final static Logger logger = LoggerFactory.getLogger(SendMessageFactory.class);

  private URLClassLoader urlClassLoader;

  public PluginManager(List<Plugin> plugins) throws MalformedURLException {
    init(plugins);
  }
  //将所有插件动态加载至JVM中
  private void init(List<Plugin> plugins) throws MalformedURLException {
    int size = plugins.size();
    URL[] urls = new URL[size];
    for (int i = 0; i < size; i++) {
      Plugin plugin = plugins.get(i);
      String filePath = plugin.getJar();
      urls[i] = new URL("file:" + filePath);
    }
    urlClassLoader = new URLClassLoader(urls);
  }

  public PluginService getInstance(String className) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
    // 插件实例化对象，得到每一个插件具体的对象
    Class<?> clazz = urlClassLoader.loadClass(className);
    Object instance = clazz.newInstance();
    return (PluginService) instance;
  }
}