"1. About java 利用 jdbc 直接连接数据库，经常取得连接，用完释放，很浪费系统资源 2. Code Java 代码 package com.cdv.mam.db; import java.sql.Connection; import java.sql.DatabaseMetaData ...."

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java 数据库连接池

1. About

java 利用 jdbc 直接连接数据库，经常取得连接，用完释放，很浪费系统资源

2. Code

Java 代码

package com.cdv.mam.db;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.SQLException;
import java.util.Properties;
import javax.sql.DataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
//import org.apache.tomcat.dbcp.dbcp.BasicDataSourceFactory;
/

tomcat 数据库连接池管理类 <br>
使用为 tomcat 部署环境 <br>
需要在类路径下准备数据库连接配置文件 dbcp.properties


*/
public class DBManager {
private static final Log log = LogFactory.getLog(DBManager.class);
private static final String configFile = "dbcp.properties";
</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 dataSource;

</span><span style="color: rgba(0, 0, 255, 1)">static</span><span style="color: rgba(0, 0, 0, 1)"> {
    Properties dbProperties </span>= <span style="color: rgba(0, 0, 255, 1)">new</span><span style="color: rgba(0, 0, 0, 1)"> Properties();
    </span><span style="color: rgba(0, 0, 255, 1)">try</span><span style="color: rgba(0, 0, 0, 1)"> {
        dbProperties.load(DBManager.</span><span style="color: rgba(0, 0, 255, 1)">class</span><span style="color: rgba(0, 0, 0, 1)">.getClassLoader()
                .getResourceAsStream(configFile));
        dataSource </span>=<span style="color: rgba(0, 0, 0, 1)"> BasicDataSourceFactory.createDataSource(dbProperties);

        Connection conn </span>=<span style="color: rgba(0, 0, 0, 1)"> getConn();
        DatabaseMetaData mdm </span>=<span style="color: rgba(0, 0, 0, 1)"> conn.getMetaData();
        log.info(</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">Connected to </span><span style="color: rgba(128, 0, 0, 1)">"</span> + mdm.getDatabaseProductName() + <span style="color: rgba(128, 0, 0, 1)">"</span> <span style="color: rgba(128, 0, 0, 1)">"</span>
                +<span style="color: rgba(0, 0, 0, 1)"> mdm.getDatabaseProductVersion());
        </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)">) {
            conn.close();
        }
    } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (Exception e) {
        log.error(</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">初始化连接池失败：</span><span style="color: rgba(128, 0, 0, 1)">"</span> +<span style="color: rgba(0, 0, 0, 1)"> e);
    }
}

</span><span style="color: rgba(0, 0, 255, 1)">private</span><span style="color: rgba(0, 0, 0, 1)"> DBManager() {
}

</span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)">*
 * 获取链接，用完后记得关闭
 * 
 * @see {@link DBManager#closeConn(Connection)}
 * @return
 </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)"> final Connection getConn() {
    Connection conn </span>= <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 </span>=<span style="color: rgba(0, 0, 0, 1)"> dataSource.getConnection();
    } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) {
        log.error(</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">获取数据库连接失败：</span><span style="color: rgba(128, 0, 0, 1)">"</span> +<span style="color: rgba(0, 0, 0, 1)"> e);
    }
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> conn;
}

</span><span style="color: rgba(0, 128, 0, 1)">/*</span><span style="color: rgba(0, 128, 0, 1)">*
 * 关闭连接
 * 
 * @param conn
 *            需要关闭的连接
 </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> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> closeConn(Connection conn) {
    </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, 0, 255, 1)">if</span> (conn != <span style="color: rgba(0, 0, 255, 1)">null</span> &amp;&amp; !<span style="color: rgba(0, 0, 0, 1)">conn.isClosed()) {
            conn.setAutoCommit(</span><span style="color: rgba(0, 0, 255, 1)">true</span><span style="color: rgba(0, 0, 0, 1)">);
            conn.close();
        }
    } </span><span style="color: rgba(0, 0, 255, 1)">catch</span><span style="color: rgba(0, 0, 0, 1)"> (SQLException e) {
        log.error(</span><span style="color: rgba(128, 0, 0, 1)">"</span><span style="color: rgba(128, 0, 0, 1)">关闭数据库连接失败：</span><span style="color: rgba(128, 0, 0, 1)">"</span> +<span style="color: rgba(0, 0, 0, 1)"> e);
    }
}

}

properties 文件（dbcp.properties）

#数据库驱动
driverClassName=com.mysql.jdbc.Driver
#数据库连接地址
url=jdbc:mysql://192.168.1.41:3306/dmc
#用户名
username=root
#密码
password=root
#连接池的最大数据库连接数。设为 0 表示无限制
maxActive=30
#最大空闲数，数据库连接的最大空闲时间。超过空闲时间，数据库连
#接将被标记为不可用，然后被释放。设为 0 表示无限制
maxIdle=10
#最大建立连接等待时间。如果超过此时间将接到异常。设为-1 表示无限制
maxWait=1000
#超过 removeAbandonedTimeout 时间后，是否进 行没用连接（废弃）的回收（默认为 false，调整为 true)
removeAbandoned=true
#超过时间限制，回收没有用 (废弃) 的连接（默认为 300 秒，调整为 180）
removeAbandonedTimeout=180

用到的 jar

java 数据库连接池

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java 数据库连接池