标签：jar包 public test rgs 文件 pac start span new
我加载的方法是:
//参数fileName是jar包的路径，processorName 是业务类的包名+类名
public static A load(String fileName, String processorName) {
String filePath = fileName;
A processor = null;
URL url;
try {
url = new URL(filePath);
} catch (MalformedURLException e1) {
e1.printStackTrace();
log.error("文件不存在");
return null;
}
URLClassLoader loader = new URLClassLoader(new URL[] { url });
try {
Class<?> processorClass = loader.loadClass(processorName);
processor = (A)processorClass.newInstance();
} catch (Exception e) {
log.error("创建业务类失败");
e.printStackTrace();
return null;
}
return processor;
}
问题：用main方法来调用这个load方法是能加载jar包中业务类a的，但是如果在自己系统里面按照正常流程走的时候调用load方法的时候 却报错：接口类A找不到， 但是接口类A是明明定义在系统内部的,（两次调用load方法的入参都是一样的）
解决方法：
parentClassLoader，即Thread.currentThread().getContextClassLoader(),就能从当前程序中查找接口类A
package com.main.java; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.net.MalformedURLException; import java.net.URL; import java.net.URLClassLoader; /** */ public class TestClassLoad2 { private static Logger LOGGER = LoggerFactory.getLogger(TestClassLoad2.class); public static void main(String[] args) { args=new String[]{"file://F:/bin/lib/test.jar","com.main.java.TestProcess"}; LOGGER.info("start"); load(args[0],args[1]); } public static Process load(String fileName, String processorName) { String filePath = fileName; Process processor = null; URL url; try { url = new URL(filePath); } catch (MalformedURLException e1) { e1.printStackTrace(); LOGGER.info("文件不存在"); return null; } URLClassLoader loader = new URLClassLoader(new URL[]{url},Thread.currentThread().getContextClassLoader()); //URLClassLoader loader = new URLClassLoader(new URL[] { url }); try { Class<?> processorClass = loader.loadClass(processorName); processor = (Process)processorClass.newInstance(); processor.display(); } catch (Exception e) { LOGGER.info("创建业务类失败"); e.printStackTrace(); return null; } return processor; } }
package com.main.java; public interface Process { void display(); }
另一个jar包的类
package com.main.java; public class TestProcess implements Process { @Override public void display() { System.out.println("test testProcess"); } }
注意事项： 两个jar包的Process接口，包路径必须一致
file://F:/bin/lib/ 也可以
标签：jar包 public test rgs 文件 pac start span new
原文地址：http://www.cnblogs.com/yangh2016/p/6180183.html
