java——数据库连接池——druid_基本使用
5. Druid：数据库连接池实现技术，由阿里巴巴提供的 1. 步骤： 1. 导入 jar 包 druid-1.0.9.jar 2. 定义配置文件： * 是 properties 形式的 * 可以叫任意名称，可以放在任意目录下 3. 加载配置文件。Properties 4. 获取数据库连接池对象：通过工厂来来获取 DruidDataSourceFactory 5. 获取连接：getConnection * 代码： //3. 加载配置文件 Properties pro = new Properties(); InputStream is = DruidDemo.class.getClassLoader().getResourceAsStream("druid.properties"); pro.load(is); //4. 获取连接池对象 DataSource ds = DruidDataSourceFactory.createDataSource(pro); //5. 获取连接 Connection conn = ds.getConnection();
2. 定义工具类 1. 定义一个类 JDBCUtils 2. 提供静态代码块加载配置文件，初始化连接池对象 3. 提供方法 1. 获取连接方法：通过数据库连接池获取连接 2. 释放资源 3. 获取连接池的方法
* 代码： public class JDBCUtils {</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">1.定义成员变量 DataSource</span> <span style="color: rgba(0, 0, 255, 1)">private</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> DataSource ds ; </span><span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)">{ </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> { </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">1.加载配置文件</span> Properties pro = <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> Properties(); pro.load(JDBCUtils.</span><span style="color: rgba(0, 0, 255, 1)">class</span>.getClassLoader().getResourceAsStream("druid.properties"<span style="color: rgba(0, 0, 0, 1)">)); </span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">2.获取DataSource</span> ds =<span style="color: rgba(0, 0, 0, 1)"> DruidDataSourceFactory.createDataSource(pro); } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (IOException e) { e.printStackTrace(); } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (Exception e) { e.printStackTrace(); } } </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 获取连接 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> Connection getConnection() <span style="color: rgba(0, 0, 255, 1)">throws</span><span style="color: rgba(0, 0, 0, 1)"> SQLException { </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> ds.getConnection(); } </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 释放资源 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> close(Statement stmt,Connection conn){ </span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)"> if(stmt != null){ try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } } if(conn != null){ try { conn.close();//归还连接 } catch (SQLException e) { e.printStackTrace(); } }</span><span style="color: rgba(0, 128, 0, 1)">*/</span><span style="color: rgba(0, 0, 0, 1)"> close(</span><span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">,stmt,conn); } </span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> close(ResultSet rs , Statement stmt, Connection conn){ </span><span style="color: rgba(0, 0, 255, 1)">if</span>(rs != <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">){ </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> { rs.close(); } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) { e.printStackTrace(); } } </span><span style="color: rgba(0, 0, 255, 1)">if</span>(stmt != <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">){ </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> { stmt.close(); } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) { e.printStackTrace(); } } </span><span style="color: rgba(0, 0, 255, 1)">if</span>(conn != <span style="color: rgba(0, 0, 255, 1)">null</span><span style="color: rgba(0, 0, 0, 1)">){ </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> { conn.close();</span><span style="color: rgba(0, 128, 0, 1)">//</span><span style="color: rgba(0, 128, 0, 1)">归还连接</span> } <span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) { e.printStackTrace(); } } } </span><span style="color: rgba(0, 128, 0, 1)">/**</span><span style="color: rgba(0, 128, 0, 1)"> * 获取连接池方法 </span><span style="color: rgba(0, 128, 0, 1)">*/</span> <span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> DataSource getDataSource(){ </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> ds; } }</span></pre>