springboot +mybatis callSettersOnNulls=true 解决使用map接收返回值值为null的问题，默认是当值为null,不会将key返回

	SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
	Properties settingsProperties = new Properties();
	// 使用log4j输出jdbc日志
	settingsProperties.setProperty("logImpl", "LOG4J");
	sqlSessionFactoryBean.setConfigurationProperties(settingsProperties);
	//查询返回Map时设置值为null
	org.apache.ibatis.session.Configuration configuration = new org.apache.ibatis.session.Configuration();
	configuration.setCallSettersOnNulls(true);
	sqlSessionFactoryBean.setConfiguration(configuration);