一、JDBC方式
// 加载驱动程序
Class.forName("com.mysql.jdbc.Driver");
//或 new com.mysql.jdbc.Driver();
// 创建数据库连接
String url = "jdbc:mysql://localhost:3306/blog";
String username = "root";
String password = "root";
Connection conn = DriverManager.getConnection(url, username, password);
// 创建 Statement
Statement stmt = conn.createStatement();
// 读取数据
String sql = "select * from blog";
ResultSet rs = stmt.executeQuery(sql);
while (rs != null && rs.next()) {
String title = rs.getString(3); // 取当前行的第二列(下标从1开始)
int id = rs.getInt("id"); // 根据列名获取
// byte[] bytes = rs.getBytes("..."); // 读取二进制
}
// 添加数据
sql = "insert into blog values ....";
int rows = stmt.executeUpdate(sql); // 返回改动的数据的行数
// 释放资源
rs.close();
stmt.close();
conn.close();
二、Web服务器连接池方式
private static void connectionPoolHelper()
{
Context context = new InitialContext();
String jndi = "java:comp/env/jdbc/mysqlds";
DataSource ds = (DataSource) context.lookup(jndi);
Connection conn = ds.getConnection();
//......
}
tomcat的配置:context.xml文件
<Resource name="jdbc/mysqlds" auth="Container"
type="javax.sql.DataSource" maxIdle="30" maxWait="10000"
maxActive="100" username="root" password="root"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/blog"/>
三、DBUtil方式
private static void dbutilHelper()
{
Context context = new InitialContext();
String jndi = "java:comp/env/jdbc/mysqlds";
DataSource ds = (DataSource) context.lookup(jndi);
QueryRunner qr = new QueryRunner(ds);
qr.query...
qr.update...
}