Java动态加载类 [英] Java Dynamically Loading a class

问题描述

我正在尝试将类动态加载到组件中。我正在使用文件选择器来选择要加载的.JAR文件，然后选择一个选项窗格来获取类的名称。

我已经拖网了如何将java文件转换为URL，以便将其加载到URLClassLoader中，我已经提出：

  File myFile = filechooser.getSelectedFile（）; 
 String className = JOptionPane.showInputDialog（
 this，Class Name，Class Name，JOptionPane.QUESTION_MESSAGE）; 
 
 URL myUrl = null; 
 try {
 myUrl = myFile.toURL（）; 
} catch（MalformedURLException e）{
} 
 
 URLClassLoader loader = new URLClassLoader（myUrl）; 
 loader.loadClass（className）; 
  

我现在收到一个'找不到符号'错误，将URL加载到URLClassLoader

解决方案

URLClassLoader的构造函数需要一组URL ，而不是一个URL。

I am attempting to load classes dynamically into a component. I am using a file chooser to select the .JAR file that will be loaded and then a option pane to get the name of the class.

I have trawled the internet looking for how to convert a java file to a URL in order to load it in URLClassLoader and I have come up with:

File myFile = filechooser.getSelectedFile();
String className = JOptionPane.showInputDialog(
    this, "Class Name:", "Class Name", JOptionPane.QUESTION_MESSAGE);

URL myUrl= null;
try {
    myUrl = myFile.toURL();
} catch (MalformedURLException e) {
}

URLClassLoader loader = new URLClassLoader(myUrl);
loader.loadClass(className);

I am now getting a 'cannot find symbol' error for loading the URL into the URLClassLoader

解决方案

The constructor of URLClassLoader takes an array of URLs, not a single URL.

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