Druid 数据库连接池

druid   数据库连接池   由阿里提供
   步骤
   1  导包   durid1.0.9 jar  包
   2  定义配置文件    必须是   properties文件    名字任意   位置也任意
   3  获得数据库连接池对象    通过  DuridDataSourceFactory获得
   4  获取连接
 具体代码如下
   package Demo3Durid;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;

public class Demo3Durid {
    public static void main(String[] args) throws Exception {
        //加载文件
        Properties pro=new Properties();
        InputStream in = Demo3Durid.class.getClassLoader().getResourceAsStream("druid.properties");
        pro.load(in);
        //获得连接池对象    通过 DuridDataSourceFactory获得
        DataSource ds = DruidDataSourceFactory.createDataSource(pro);
        //获取连接
        Connection conn = ds.getConnection();
        System.out.println(conn);

    }

}

利用工具类 实现  Druid连接池
package JdbcUtils;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

/*
*Druid工具类
**/
public class JdbcUtils {
    //定义成员变量   DateSource
    private static DataSource ds;

    static{
        //加载配置文件
        try {
            Properties pro=new Properties();
            InputStream in = JdbcUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            pro.load(in);
             ds = DruidDataSourceFactory.createDataSource(pro);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }
     public static Connection getConnection() throws SQLException {
        return ds.getConnection();
     }
     //释放资源
    public static void close(AutoCloseable... c){
        for(AutoCloseable a: c){
            if(a!=null){
                try {
                    a.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

}

连接
package JdbcUtils;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class Demo4Druid {

    private static PreparedStatement ps;
    private static Connection conn;

    public static void main(String[] args) {
        //完成一个添加操作

        try {
            //获得连接
            conn = JdbcUtils.getConnection();
            //定义sql语句
            String sql="insert into coount values(null,?,?)";
            //获得执行语句
            ps = conn.prepareStatement(sql);
            //给？赋值
            ps.setString(1,"李登");
            ps.setDouble(2,20000);
            //执行sql
            int i = ps.executeUpdate();
            System.out.println(i);

        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            JdbcUtils.close(ps,conn);
        }
    }
}