Java中class.forName和classLoader都可用来对类进行加载。前者除了将类的.class文件加载到jvm中之外，还会对类进行解释，执行类中的static块。而classLoader只干一件事情，就是将.class文件加载到jvm中，不会执行static中的内容,只有在newInstance才会去执行static块。Class.forName(name, initialize, loader)带参函数也可控制是否加载static块。并且只有调用了newInstance()方法采用调用构造函数，创建类的对象 示例代码如下:
package com.blueray.java.test;
public class ClassLoaderTest {
/**
* @param args
*/
public static void main(String[] args) {
ClassLoader classLoader=StaticSample.class.getClassLoader();
try {
System.out.println("Before load class");
Class clazz=classLoader.loadClass(StaticSample.class.getName());
System.out.println("After load class.");
System.out.println("executing newInstance");
clazz.newInstance();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
StaticSample:
package com.blueray.java.test;
public class StaticSample {
static{
System.out.println(StaticSample.class.getName()+" is loading the static block");
}
public StaticSample(){
System.out.println("StaticSample Constructor is executing.");
}
}
运行结果如下：
Before load class
After load class.
executing newInstance
com.blueray.java.test.StaticSample is loading the static block
StaticSample Constructor is executing.