throw和throws的区别

throw

throw关键字用来在程序中（方法体中）明确的抛出异常

@SuppressWarnings("unchecked")
private <T> T execute(final ChannelCallback<T> action, final ConnectionFactory connectionFactory) {
	if (this.retryTemplate != null) {
		try {
			return this.retryTemplate.execute(new RetryCallback<T, Exception>() {

				@Override
				public T doWithRetry(RetryContext context) throws Exception {
					return RabbitTemplate.this.doExecute(action, connectionFactory);
				}

			}, (RecoveryCallback<T>) this.recoveryCallback);
		}
		catch (Exception e) {
			if (e instanceof RuntimeException) {
				// 抛出异常类实例
				throw (RuntimeException) e;
			}
			throw RabbitExceptionTranslator.convertRabbitAccessException(e);
		}
	}
	else {
		return doExecute(action, connectionFactory);
	}
}

throws

throws语句用来声明方法不能处理的异常，throws 用在函数上，后面跟的是异常类

// 声明方法不能处理的异常IllegalStateException 
private MessageConverter getRequiredMessageConverter() throws IllegalStateException {
	MessageConverter converter = this.getMessageConverter();
	if (converter == null) {
		throw new AmqpIllegalStateException(
				"No 'messageConverter' specified. Check configuration of RabbitTemplate.");
	}
	return converter;
}