JDBC连接数据库

1.

public void testDriver() throws SQLException{
         //    创建Driver实现类对象    
         Driver driver = new com.mysql.jdbc.Driver();
         
         // 准备连接数据库的基本信息
         String url = "jdbc:mysql://localhost:3306/ksy";
         Properties info = new Properties();
         info.put("user", "root");
         info.put("password","");
         
         // 调用Driver接口的connect(url, info)来回去数据库连接
         Connection conn = (Connection) driver.connect(url, info);
         
         
         // com.mysql.jdbc.JDBC4Connection@16290fbc
         System.out.println(conn);
    }
    

2.

/**
     * 编写通风用的方法，不修改源程序的情况下，可以获取任何数据库的连接
     * 解决方案： 把数据库驱动Driver实现类的全类名、url、user、password放在一个配置文件中
     *         通过修改配置稳健的方式实现和具体数据库解耦
     * @throws Exception 
     */
    public Connection getConnection() throws Exception {
        String driverClass = null;
        String jdbcUrl = null;
        String user = null;
        String password = null;
        
        // 读取类路径下的文件
        InputStream is = getClass().getClassLoader().getResourceAsStream("jdbc.properties");
        Properties properties = new Properties();
        properties.load(is);
        
        driverClass = properties.getProperty("driverClass");        
        jdbcUrl = properties.getProperty("jdbcUrl");
        user = properties.getProperty("user");
        password = properties.getProperty("password");
        
        Driver driver = (Driver) Class.forName(driverClass).newInstance();
        
        Properties info = new Properties();
        info.put("user", user);
        info.put("password", password);
        
        Connection conn = (Connection) driver.connect(jdbcUrl, info);
        return conn;
    }
     
    public void testGetConnection() throws Exception {
        // com.mysql.jdbc.JDBC4Connection@2f833eca
        System.out.println( getConnection());
    }

3.

driverClass = com.mysql.jdbc.Driver
jdbcUrl = jdbc:mysql://localhost:3306/ksy
user = root
password = 

4.

/**
     * DriverManage是驱动的管理类
     * @throws Exception 
     * 
     */
     
    public void testDriverManage() throws Exception {
        //驱动的全类名
        String driverClass = null;
        String jdbcUrl = null;
        String user = null;
        String password = null;
        
        // 读取类路径下的文件
        InputStream is = getClass().getClassLoader().getResourceAsStream("jdbc.properties");
        Properties properties = new Properties();
        properties.load(is);
        
        driverClass = properties.getProperty("driverClass");        
        jdbcUrl = properties.getProperty("jdbcUrl");
        user = properties.getProperty("user");
        password = properties.getProperty("password");
        
        // 加载驱动程序（对应的Driver实现类中有注册驱动的静态代码块）
        Class.forName(driverClass);
        
        // 获取数据库连接
        Connection conn = (Connection) DriverManager.getConnection(jdbcUrl, user, password);
        System.out.println(conn);
    }

5.

    /**
     * 使用DBCP数据库连接池
     * @throws Exception 
     */
    public void testDBCP() throws Exception {
        BasicDataSource dataSource = null;
        // 创建DBCP数据源实例
        dataSource = new BasicDataSource();
        
        // 为数据源实例指定属性
        dataSource.setUsername("root");
        dataSource.setPassword("");
        dataSource.setUrl("jdbc:mysql:///ksy");
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        
        // 指定数据源的一些属性
        // 数据库连接池中初始化连接数
        dataSource.setInitialSize(5);
        
        // 同一时刻向数据库申请的最大连接数
        dataSource.setMaxActive(5);
        
        // 在数据库连接中保存的最少的空闲连接数
        dataSource.setMinIdle(10);
        
        // 等待连接池分配的最长时间
        dataSource.setMaxWait(1000);
    
        // 从数据源中获取数据库连接
        // jdbc:mysql:///ksy, UserName=root@, MySQL Connector Java
        System.out.println(dataSource.getConnection());
        
        // class org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper
        System.out.println(dataSource.getConnection().getClass());
    }
    
    

6.

public void testDBCPWithDataSourceFactory() throws Exception {
        
        // 加载配置文件
        Properties properties = new Properties();
        InputStream is = getClass().getClassLoader().getResourceAsStream("dbcp.properties");
        properties.load(is);
        
        // 通过BasicDataSourceFactory.createDataSource(properties)
        // 创建dataSource实例
        final DataSource dataSource = BasicDataSourceFactory.createDataSource(properties);
        
        // BasicDataSource dasicDataSource = (BasicDataSource) dataSource;
        // 5
        // System.out.println(dasicDataSource.getMaxActive());
        
        // 从dataSource中获取实例连接
        // jdbc:mysql://localhost:3306/ksy, UserName=root@, MySQL Connector Java
         System.out.println(dataSource.getConnection().getClass());
}

7.

username = root
password = 
driverClass = com.mysql.jdbc.Driver
url = jdbc:mysql://localhost:3306/ksy
initialSize = 5
maxActive = 5
minIdle = 5
maxWait = 5000

8.

public void testC3p0() throws Exception {
        ComboPooledDataSource cpds = new ComboPooledDataSource();
        cpds.setDriverClass("com.mysql.jdbc.Driver");
        cpds.setJdbcUrl("jdbc:mysql://localhost:3306/ksy");
        cpds.setUser("root");
        cpds.setPassword("");
        // com.mchange.v2.c3p0.impl.NewProxyConnection@5ddc0e7a
        System.out.println(cpds.getConnection());
    }
    
    

9.

public void testC3p0WithConfigFile() throws SQLException {
        DataSource dataSource = new ComboPooledDataSource("helloc3p0");
        // com.mchange.v2.c3p0.impl.NewProxyConnection@11e9c82e        
        System.out.println(dataSource.getConnection());
    }