加载properties属性文档常用的三种方式

假设c3p0.properties在src的根目录下。
//1.通过File类去加载properties文件(只适用于普通的Java工程)。
Properties prop = new Properties();
File src = new File("src/c3p0.properties");
prop.load(new FileInputStream(src));
System.out.println(prop.getProperty("c3p0.user"));
//2.通过类加载器去加载properties文件
Properties prop = new Properties();
InputStream in = MyDBUtils.class.getClassLoader().getResourceAsStream("c3p0.properties");
prop.load(in);
System.out.println(prop.getProperty("c3p0.user"));
//3.使用ResourceBundle加载properties文档ResourceBundle resource = ResourceBundle.getBundle("c3p0");//注意：无需加扩展名properties
System.out.println(resource.getString("c3p0.user"));