getResourceAsStream方法 读取资源文件

PropertiesServlet.java

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Properties;

public class PropertiesServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //  get的路径是编译好的target文件夹下的路径
        //  / 代表当前web项目（servlet-02-1.0-SNAPSHOT）
        //  一定要看准编译后的资源文件的路径
        InputStream is = this.getServletContext().getResourceAsStream("/WEB-INF/classes/db.properties");
        //  返回的流咱们就可以用了
        Properties prop = new Properties();
        prop.load(is);
        String username = prop.getProperty("username");
        String passowrd = prop.getProperty("password");

        PrintWriter writer = resp.getWriter();
        writer.println(username);
        writer.println(passowrd);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }

}

resources/db.properties

username=mahe666
password=12345

web.xml

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
				http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0"
         metadata-complete="true">

    <servlet>
        <servlet-name>propertiesServlet</servlet-name>
        <servlet-class>com.mahe666.servlet.PropertiesServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>propertiesServlet</servlet-name>
        <url-pattern>/propertiesServlet</url-pattern>
    </servlet-mapping>

</web-app>