通过URLClassLoader实现动态加载指定路径上所有Jar

通过URLClassLoader实现动态加载指定路径下所有Jar

示例代码：

package test.tool.gui.dbtool.util;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import org.apache.log4j.Logger;
import test.tool.gui.dbtool.consts.Const;

public class JarLoadUtil {

	private static Logger log = Logger.getLogger(JarLoadUtil.class);
	private static URL lib_url = ClassLoader.getSystemClassLoader().getResource("lib");
	private static URLClassLoader loader = null;
	/*
	 * 加载lib目录下所有jar文件，并返回相应的的URLClassLoader
	 */
	public static URLClassLoader getURLClassLoader(){	
		
		if(loader == null){		
			String fileNames[] = listFileNames();
			if(fileNames != null && fileNames.length > 0){	 
				URL urls[] = new URL[fileNames.length];
				for(int i = 0;i < fileNames.length;i++){
					try {
						urls[i] = new URL(lib_url+"/"+fileNames[i]);
					} catch (MalformedURLException e) {
						if("true".equals(ConfigUtil.getConfInfo().get(Const.IS_LOG)+"")){				
							log.error("加载lib目录下jar文件出错！",e);
						}
						throw new RuntimeException("加载lib目录下jar文件出错！",e);
					}
				}
				loader = new URLClassLoader(urls);
		}
		}
		return loader;
	}
	/*
	 * 查询lib目录下的所有文件名称
	 */
	private static String[] listFileNames(){
		File file_directory = new File("lib");
		return file.list();
	}
}

 

 

使用：

URLClassLoader loader = JarLoadUtil.getURLClassLoader();
Class<?> clazz = loader.loadClass(ds.getDriverClassName());
Driver driver = (Driver)clazz.newInstance();		
			
Properties p = new Properties();
p.put("user", ds.getUsername());
p.put("password", ds.getPwd());		
			
Connection con = driver.connect(ds.getUrl(), p);

 

http://huangqiqing123.iteye.com/blog/1461624