04.ServletContext读取资源文件

对于web应用，资源文件一般有xml文件和properties文件，如果配置内容是有关系的，则用xml文件如果是没有关系的则用properties文件。

例如配置数据库则用properties文件。在source下新建文件db.properties。

读取：

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/classes/db.properties");

//一下为模板方法，不许哟啊改变(其实properties就是一个map)
Properties p = new Properties();
p.load(in);

String url = p.getProperty("url");
String username = p.getProperty("username");
String password = p.getProperty("password");

System.out.println(url);
System.out.println(username);
System.out.println(password);

}

传统IO流方法读取：

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//得到资源的绝对路径
String path = this.getServletContext().getRealPath("/WEB-INF/classes/db.properties");
InputStream in = new FileInputStream(path);

Properties p = new Properties();
p.load(in);

String url = p.getProperty("url");
String username = p.getProperty("username");
String password = p.getProperty("password");

System.out.println(url);
System.out.println(username);
System.out.println(password);

}

servlet方式：

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//得到资源的绝对路径
String path = this.getServletContext().getRealPath("/WEB-INF/classes/db.properties");
InputStream in = new FileInputStream(path);

Properties p = new Properties();
p.load(in);

String url = p.getProperty("url");
String username = p.getProperty("username");
String password = p.getProperty("password");

System.out.println(url);
System.out.println(username);
System.out.println(password);

}