JDBC-Connection

新建Maven工程

pom.xml

<dependencies>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>8.0.15</version>
    </dependency>
    <dependency>
        <groupId>org.junit.jupiter</groupId>
        <artifactId>junit-jupiter-api</artifactId>
        <version>5.4.0</version>
        <scope>test</scope>
    </dependency>
</dependencies>

<build>
    <plugins>
        <!-- 指定jdk -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
    </plugins>
</build>

數據庫信息

driver=com.mysql.cj.jdbc.Driver
jdbcUrl=jdbc:mysql://192.168.8.136:3306/jdbc
user=root
password=root

獲取鏈接

Driver

/**
 * Driver 是一個接口: 可以通過 Driver 的實現類對象獲取數據庫連接
 */
@Test
public void testDriver() throws SQLException {
    // 創建 Driver 實現類對象
    Driver driver = new com.mysql.cj.jdbc.Driver();

    // 准備連接數據庫信息: url, user, password
    String url = "jdbc:mysql://192.168.8.136:3306/jdbc";
    Properties info = new Properties();
    info.put("user", "root");
    info.put("password", "root");

    // 調用 Driver 接口的　connect(url, info) 獲取數據庫連接
    Connection connection = driver.connect(url, info);
    
    System.out.println(connection);
}

@Test
public void getConnection() throws Exception{
    // 讀取類路徑下的 jdbc.properties 文件
    InputStream in = getClass().getClassLoader().getResourceAsStream("jdbc.properties");
    Properties properties = new Properties();
    properties.load(in);

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

    //通過反射 Driver 對象
    Driver driver = (Driver) Class.forName(driverClass).newInstance();

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

    //通過 Driver 的 connect 方法獲取數據庫連接
    Connection connection = driver.connect(jdbcUrl, info);

    System.out.println(connection);
}

DriverManager

/**
 * DriverManager 是驅動的管理類
 * 1). 可以通過重載的 getConnection() 方法獲取數據庫連接. 較為方便
 * 2). 可以同時管理多個驅動程序: 若注冊了多個數據庫連接, 則調用 getConnection()
 * @throws Exception
 */
@Test
public void testDriverManager() throws Exception{
    // 准備連接數據庫
    String driverClass = "com.mysql.cj.jdbc.Driver";
    String jdbcUrl = "jdbc:mysql://192.168.8.136/jdbc";
    String user = "root";
    String password = "root";

    // 加載數據庫驅動程序(對應的 Driver 實現類中有注冊驅動的靜態代碼塊
    Class.forName(driverClass);
    // 通過 DriverManager 的 getConnection() 方法獲取數據庫連接
    Connection connection = DriverManager.getConnection(jdbcUrl, user, password);
    
    System.out.println(connection);
}

@Test
public void getConnection2() throws Exception{
    Properties properties = new Properties();
    InputStream in = this.getClass().getClassLoader().getResourceAsStream("jdbc.properties");
    properties.load(in);

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

    // 加載數據庫驅動程序(對應的 Driver 實現類中有注冊驅動的靜態代碼塊)
    Class.forName(driver);
    // 通過 DriverManager 的 getConnection() 方法獲取數據庫連接.
    Connection connection = DriverManager.getConnection(jdbcUrl, user, password);
    
    System.out.println(connection);
}

 

---

oracle官方JDBC文檔