Properties    props = new Properties();

    String PATH="jdbc.properties";

    InputStream in = PropertyTest.class.getClassLoader().getResourceAsStream(PATH);

    props.load(in);

    String value=props.getProperty("user");

  Properties    props = new Properties();

  String PATH="E:\\JavaDemo\\src\\main\\resource\\jdbc.properties";

  InputStream in = new BufferedInputStream(new FileInputStream( PATH ));

  props.load(in);

  String value=props.getProperty("user");

public class PropertyUtil {
   //将要读取的properties的文件名

    private static  String propertiesFileName="jdbc.properties";

    private static final Logger logger = Logger.getLogger(PropertyUtil.class);

    private static Properties props= new Properties();

    static{

        logger.info("执行静态代码块loadProps()，保存在jvm中，避免多次执行。");

        loadProps();

    }

    synchronized static private void loadProps(){

        logger.info("开始加载properties文件内容.......");

        InputStream in = null;

        try {

//　　　　　　　<!--第一种，通过类加载器进行获取properties文件流，路径为相对路径-->

            in = PropertyUtil.class.getClassLoader().getResourceAsStream(propertiesFileName);

//　　　　　　  <!--第二种，通过类进行获取properties文件流-->

            //in = PropertyUtil.class.getResourceAsStream("propertiesFileName");

            props.load(in);

        } catch (FileNotFoundException e) {

            logger.error("properties文件未找到");

        } catch (IOException e) {

            logger.error("出现IOException");

        } finally {

            try {

                if(null != in) {

                    in.close();

                }

            } catch (IOException e) {

                logger.error("properties文件流关闭出现异常");

            }

        }

        logger.info("加载properties文件内容完成...........");

    }

    public static String getProperty(String key){

        if(null == props) {

            loadProps();

        }

        return props.getProperty(key);

    }

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

        if(null == props) {

            loadProps();

        }

        return props.getProperty(key, defaultValue);

    }

}