package com.shaocoder.connection;

import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;

public class ConnectionTest {
	public static void main(String[] args) {
		Connection conn = null;
		try {
			//1.數(shù)據(jù)庫連接的4個(gè)基本要素
			//①JDBC URL用于標(biāo)識(shí)一個(gè)被注冊(cè)的驅(qū)動(dòng)程序，驅(qū)動(dòng)程序管理器通過這個(gè)URL選擇正確的驅(qū)動(dòng)程序，從而建立到數(shù)據(jù)庫的連接；
			//jdbc：表示URL中的協(xié)議
			//mysql：子協(xié)議，用于標(biāo)識(shí)mysql數(shù)據(jù)庫驅(qū)動(dòng)程序
			//localhost:本機(jī)的IP地址
			//3306：端口號(hào)
			//test：表示訪問test數(shù)據(jù)庫
			String url = "jdbc:mysql://localhost:3306/test";
			//user:登錄數(shù)據(jù)庫的用戶名
			String user = "root";
			//password:用戶名對(duì)應(yīng)的密碼，這些都是自己之前設(shè)定的
			String password = "123456";
			//mySql的驅(qū)動(dòng)：com.mysql.jdbc.Driver
			String driverName = "com.mysql.jdbc.Driver";
			
			//2.實(shí)例化Driver
			Class clazz = Class.forName(driverName);
			Driver driver = (Driver) clazz.newInstance();
			
			//3.通過DriverManager來注冊(cè)驅(qū)動(dòng)
			DriverManager.registerDriver(driver);
			//4.通過DriverManager的getConnection方法，獲取Connection類的對(duì)象
			conn = DriverManager.getConnection(url, user, password);
			//5.打印出conn對(duì)象
			System.out.println(conn);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try {
				//當(dāng)conn不為空時(shí)
				if(conn != null) 
					//關(guān)閉conn資源
					conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}
}

package com.shaocoder.connection;

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

public class ConnectionTest {

	public static void main(String args[]) {
		InputStream is = null;
		Connection conn = null;
		try {
			//通過類加載器訪問jdbc.properties文件，轉(zhuǎn)化為輸入流
			is = ClassLoader.getSystemClassLoader().getResourceAsStream("jdbc.properties");
			Properties pros = new Properties();
			pros.load(is);
			
			String user = pros.getProperty("user");
			String password = pros.getProperty("password");
			String url = pros.getProperty("url");
			String driverClass = pros.getProperty("driverClass");
			
			Class.forName(driverClass);
			
			conn = DriverManager.getConnection(url, user, password);
			
			System.out.println(conn);
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			
			try {
				if(conn != null)
					conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			try {
				if(is != null)
					is.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
				
		}
		
	}
}