對於java程式設計師來說，外掛化是一件很酷的功能，小二有幸在工作中實現了此功能。

背景：

需要將mysql的資料通過canal同步至kafka/mysql/hdfs等

實現 直接上程式碼

/**
 * 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);
    }
    //將所有外掛動態載入至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 {
        // 外掛例項化物件，得到每一個外掛具體的物件
        Class<?> clazz = urlClassLoader.loadClass(className);
        Object instance = clazz.newInstance();
        return (PluginService) instance;
    }
}
 

然後就可以進行外掛的呼叫了。 有一點需要注意，那就是效率。反射真的降低效率嗎？請移步

http://blog.csdn.net/jsjsjs1789/article/details/78719605