[八]数据库连接池与JDBC。纳尼？连接池关JDBC神马事？
起源
为何放弃DriverManager
//1、注册驱动Class.forName("com.mysql.jdbc.Driver");//数据库连接所需参数String user = "root";String password = "123456";String url = "jdbc:mysql://localhost:3306/sampledb?useUnicode=true&characterEncoding=utf-8";//2、获取连接对象Connection conn = DriverManager.getConnection(url, user, password);
连接池
数据源
实现
核心架构
DataSource
基本实现 - 生成标准的 Connection 对象
连接池实现 - 生成自动参与连接池的 Connection 对象。此实现与中间层连接池管理器一起使用。
分布式事务实现 - 生成一个 Connection 对象，该对象可用于分布式事务，大多数情况下总是参与连接池。此实现与中间层事务管理器一起使用，大多数情况下总是与连接池管理器一起使用。
API
Connection getConnection()Connection getConnection(String username, String password)
小结
应用
数据库连接池示例
package jdbc;import com.alibaba.druid.pool.DruidDataSource;import com.mchange.v2.c3p0.ComboPooledDataSource;import java.sql.Connection;import java.sql.ResultSet;import java.sql.Statement;import org.apache.commons.dbcp2.BasicDataSource;public class MyDataSource {public static void main(String[] args) throws Exception {String user = "root";String password = "123456";String url = "jdbc:mysql://localhost:3306/sampledb?useUnicode=true&characterEncoding=utf-8";//1.获取连接// Connection conn = getDHCPConnection(user,password,url);//Connection conn = getC3P0Connection(user,password,url);Connection conn = getDruidConnection(user, password, url);String sql = "select * from student limit 0,10";//2、获得sql语句执行对象Statement stmt = conn.createStatement();//3、执行并保存结果集ResultSet rs = stmt.executeQuery(sql);//4、处理结果集while (rs.next()) {System.out.print("id:" + rs.getInt(1));System.out.print(",姓名:" + rs.getString(2));System.out.print(",年龄:" + rs.getInt(3));System.out.println(",性别:" + rs.getString(4));}conn.close();stmt.close();rs.close();}public static Connection getDruidConnection(String user, String password, String url)throws Exception {DruidDataSource ds = new DruidDataSource();ds.setUsername(user);ds.setPassword(password);ds.setUrl(url);ds.setDriverClassName("com.mysql.jdbc.Driver");return ds.getConnection();}public static Connection getC3P0Connection(String user, String password, String url)throws Exception {ComboPooledDataSource cpds = new ComboPooledDataSource();cpds.setUser(user);cpds.setPassword(password);cpds.setJdbcUrl(url);cpds.setDriverClass("com.mysql.jdbc.Driver");return cpds.getConnection();}public static Connection getDHCPConnection(String user, String password, String url)throws Exception {BasicDataSource dataSource = new BasicDataSource();dataSource.setUsername(user);dataSource.setPassword(password);dataSource.setUrl(url);dataSource.setDriverClassName("com.mysql.jdbc.Driver");Connection connection = dataSource.getConnection();return connection;}}
总结
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注：非技术讲解配图均来源于网络
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