jdbc

import com.mysql.jdbc.AbandonedConnectionCleanupThread;

import java.sql.Connection;
import java.sql.Driver;
import java.sql.SQLException;
import java.util.Properties;


public class MysqlTest {
    public static void main(String[] args) throws SQLException {

        Driver driver = new com.mysql.jdbc.Driver();

        String url = "jdbc:mysql://localhost:3306/wlyy";

        Properties info = new Properties();
        info.put("user", "root");
        info.put("password", "root");

        Connection connection = driver.connect(url, info);
        System.out.println(connection);

    }
}

import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.Driver;
import java.util.Properties;

/**
 * Created with IntelliJ IDEA.
 * User: Administrator
 * Date: 17-6-5
 * Time: 下午10:25
 * To change this template use File | Settings | File Templates.
 */
public class MySqlInputStream {
    public Connection getConnection() throws Exception {

        InputStream inputStream = getClass().getResourceAsStream("jdbc.property");

        Properties properties = new Properties();
        properties.load(inputStream);

        String driver = properties.getProperty("driver");
        String url = properties.getProperty("url");
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");

        Properties info = new Properties();
        info.put("user",user);
        info.put("password", password);

        Driver d = (Driver) Class.forName(driver).newInstance();
        Connection connection = d.connect(url, info);

        return connection;
    }

    public static void main(String[] args) throws Exception {
        MySqlInputStream m = new MySqlInputStream();
        System.out.println(m.getConnection());
    }
}

package com.atguigu.jdbc;

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

/**
 * 操作 JDBC 的工具类. 其中封装了一些工具方法 Version 1
 */
public class JDBCTools {

    public static void release(ResultSet rs, 
            Statement statement, Connection conn) {
        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        
        
        if (statement != null) {
            try {
                statement.close();
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }

        if (conn != null) {
            try {
                conn.close();
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
    
    /**
     * 关闭 Statement 和 Connection
     * @param statement
     * @param conn
     */
    public static void release(Statement statement, Connection conn) {
        if (statement != null) {
            try {
                statement.close();
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }

        if (conn != null) {
            try {
                conn.close();
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }

    /**
     * 1. 获取连接的方法. 通过读取配置文件从数据库服务器获取一个连接.
     * 
     * @return
     * @throws Exception
     */
    public static Connection getConnection() throws Exception {
        // 1. 准备连接数据库的 4 个字符串.
        // 1). 创建 Properties 对象
        Properties properties = new Properties();

        // 2). 获取 jdbc.properties 对应的输入流
        InputStream in = JDBCTools.class.getClassLoader().getResourceAsStream(
                "jdbc.properties");

        // 3). 加载 2） 对应的输入流
        properties.load(in);

        // 4). 具体决定 user, password 等4 个字符串.
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String jdbcUrl = properties.getProperty("jdbcUrl");
        String driver = properties.getProperty("driver");

        // 2. 加载数据库驱动程序(对应的 Driver 实现类中有注册驱动的静态代码块.)
        Class.forName(driver);

        // 3. 通过 DriverManager 的 getConnection() 方法获取数据库连接.
        return DriverManager.getConnection(jdbcUrl, user, password);
    }

}