Java DataBase Connectivity
Java數據庫連接

寫在前面

• 注冊驅動Class.forName()
• 獲取連接DriverManager.getConnection()

詳細過程

• mysql連接的url

String urlString = "jdbc:mysql://localhost:3306/數據庫名";

• 方式一

//創建mysql驅動對象
Driver driver = new com.mysql.jdbc.Driver();
//設置訪問數據庫的用戶名和密碼
Properties properties = new Properties();
properties.setProperty("user", "用戶名");
properties.setProperty("password", "密碼");
//建立連接
Connection connection = driver.connect(urlString, properties);
//關閉連接
connection.close();

• 方式二

//創建mysql驅動對象
Driver driver = new com.mysql.jdbc.Driver();
//注冊驅動
DriverManager.registerDriver(driver);
//通過DriverManager獲取連接對象
Connection connection = DriverManager.getConnection(urlString, "用戶名", "密碼");
//關閉連接
connection.close();

• 方式三

//注冊驅動
Class.forName("com.mysql.jdbc.Driver");
//獲取連接
Connection connection = DriverManager.getConnection(urlString, "用戶名", "密碼");
//關閉連接
connection.close();

自定義的JdbcUtil類用來獲取Connection對象

• properties文件

url=jdbc:mysql://localhost:3306/javawu
user=root
password=root
driver=com.mysql.jdbc.Driver

• JdbcUtil類

package com.javawu.util;
import java.io.FileInputStream;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class JdbcUtil {
    
    private static String driverString;
    private static String urlString;
    private static String userString;
    private static String passwordString;
    
    static {
        try {
            FileInputStream fileInputStream = new FileInputStream("./bin/db.properties");
            Properties properties = new Properties();
            properties.load(fileInputStream);
            urlString = properties.getProperty("url");
            driverString = properties.getProperty("driver");
            userString = properties.getProperty("user");
            passwordString = properties.getProperty("password");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        
    }
    //獲取連接對象
    public static Connection getConnection(){
        Connection connection = null;
        try {
            Class.forName(driverString);
            connection = DriverManager.getConnection(urlString, userString, passwordString);
        } catch (ClassNotFoundException | SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return connection;
    }
    
    //關閉相關對象、
    public static void close(Connection connection, Statement statement) {
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    public static void closeAll(Connection connection, Statement statement, ResultSet resultSet) {
        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}