InvocationTargetException异常由Method.invoke(obj, args...)方法抛出。当被调用的方法的内部抛出了异常而没有被捕获时，将由此异常接收。

示例：

package com.zzj.test.reflect;

public class Reflect {
	public void run(int i) throws ZeroException {
		B b = new B();
		b.run(i);
	}
}

class B {
	public void run(int i) throws ZeroException {
		if (i < 0) {
			throw new ZeroException("参数不能小于零！");
		}
		System.out.println("参数：" + i);

	}
}

class ZeroException extends Exception {
	private static final long serialVersionUID = 1L;

	private String detailMessage;

	public ZeroException(String detailMessage) {
		this.detailMessage = detailMessage;
	}

	public String getMessage() {
		return detailMessage;
	}
}

测试：

package com.zzj.test.reflect;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Test {
	public static void main(String[] args) {
		try {
			Class<?> clazz = Class.forName("com.zzj.test.reflect.Reflect");
			Method method = clazz.getMethod("run", int.class);
			method.invoke(clazz.newInstance(), -1);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			System.out.println("此处接收被调用方法内部未被捕获的异常");
			e.printStackTrace();
		} catch (InstantiationException e) {
			e.printStackTrace();
		}
	}
}

输出：

此处接收被调用方法内部未被捕获的异常
java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.zzj.test.reflect.Test.main(Test.java:11)
Caused by: com.zzj.test.reflect.ZeroException: 参数不能小于零！
	at com.zzj.test.reflect.B.run(Reflect.java:13)
	at com.zzj.test.reflect.Reflect.run(Reflect.java:6)
	... 5 more

也可以直接打印目标异常：

package com.zzj.test.reflect;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Test {
	public static void main(String[] args) {
		try {
			Class<?> clazz = Class.forName("com.zzj.test.reflect.Reflect");
			Method method = clazz.getMethod("run", int.class);
			method.invoke(clazz.newInstance(), -1);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SecurityException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		} catch (IllegalArgumentException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			System.out.println("此处接收被调用方法内部未被捕获的异常");
			Throwable t = e.getTargetException();// 获取目标异常
			t.printStackTrace();
		} catch (InstantiationException e) {
			e.printStackTrace();
		}
	}
}

输出：

此处接收被调用方法内部未被捕获的异常
com.zzj.test.reflect.ZeroException: 参数不能小于零！
	at com.zzj.test.reflect.B.run(Reflect.java:13)
	at com.zzj.test.reflect.Reflect.run(Reflect.java:6)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.zzj.test.reflect.Test.main(Test.java:11)