两种方式读取不同位置的文件——读取jdbc.properties文件，读取web应用下的资源文件

①在src下创建jdbc.properties文件

②jdbc.properties中

user=root
password=123456
url=jdbc:mysql://localhost:3306/qf
driverClass=com.mysql.cj.jdbc.Driver

③创建名为Connection的Java文件

④在Connection.java中编写代码

package dataconnection;

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import org.junit.Test;

public class Connetion {
	@Test
	public static void getContection() {
		Connection conn = null;
		try {
			// 获取类的加载器
			InputStream is = Connetion.class.getClassLoader().getResourceAsStream("jdbc.properties");
			Properties pros = new Properties();
			pros.load(is);

			String user = pros.getProperty("user");				 //获取jdbc.properties中名为user内容的值
			String password = pros.getProperty("password");		 //获取jdbc.properties中名为password内容的值
			String url = pros.getProperty("url");				 //获取jdbc.properties中名为url内容的值
			String driverClass = pros.getProperty("driverClass");//获取jdbc.properties中名为driverClass内容的值

			Class.forName(driverClass);

			conn = DriverManager.getConnection(url, user, password);
			System.out.println(conn);
		} catch (Exception e) {
			e.printStackTrace();
		}
//		关闭连接
		finally {
			try {
				if(conn!=null) {
					conn.close();
				}
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

	}
}

①在WebContent→WEB-INF下建立itcast.properties文件

（itcast.properties在新建在WEB-INF的任意位置）（名字任意）

②在TestServlet.java中编写代码

package jdbc_1;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(value="/a")
public class TestServlet extends HttpServlet{
	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}
	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		
		ServletContext context = this.getServletContext();
	    InputStream in = context.getResourceAsStream("WEB-INF/itcast.properties");
	    
	    Properties prop = new Properties();
	    //读取资源文件
	    prop.load(in);
	    
	    String user = prop.getProperty("user");
		String password = prop.getProperty("password");
		String url = prop.getProperty("url");
		String driverClass = prop.getProperty("driverClass");

	  	System.out.println(user);
	}
}