电商项目之用PropertiesUtil帮助类来读取(xx.properties)配置文件(重点)

1、tomcat启动的时候就要读取到里面的配置

/**
 * 读取配置文件的帮助类，最开始用的地方是MD5里面
 */
public class PropertiesUtil {

    private static Logger logger = LoggerFactory.getLogger(PropertiesUtil.class);

    private static Properties props;

    //静态代码块只执行一次，在类加载的时候执行
    static {
        String fileName = "mmall.properties";
        props = new Properties();
        try {
            props.load(new InputStreamReader(PropertiesUtil.class.getClassLoader().getResourceAsStream(fileName),"UTF-8"));
        } catch (IOException e) {
            logger.error("配置文件读取异常",e);
        }
    }

    public static String getProperty(String key){
        String value = props.getProperty(key.trim());
        if(StringUtils.isBlank(value)){
            return null;
        }
        return value.trim();
    }

    public static String getProperty(String key,String defaultValue){

        String value = props.getProperty(key.trim());
        if(StringUtils.isBlank(value)){
            value = defaultValue;
        }
        return value.trim();
    }



}