데이터베이스 연결 풀

1.    ，  connection  ，  ，  ，  。

DataSource 인터페이스

1. java.sql
2. getConnection();--  
3.  ：  C3PO ， Druid  
4.  connnection ， close（） ， \

## C3P0 ##

## c3p0 사용 ##

jar 패키지 가져오기

정의 프로필 이름은 c3p0.properties 또는 c3p0-config.xml `

 com.mysql.cj.jdbc.Driver jdbc:mysql://localhost:3306/db3?serverTimezone=UTC root root

5
10
3000
     

      

com.mysql.cj.jdbc.Driver
jdbc:mysql://localhost:3306/db3?serverTimezone=UTC
root
root


5
8
1000
 
`

연결 풀 개체 만들기 - ComboPooled DataSource

연결 얻기 = = getConnecction();

 

1. public class C3p0demo {
public static void main(String[] args) throws SQLException {
    // 
    DataSource ds = new ComboPooledDataSource();
    Connection conn = ds.getConnection();
    conn.close();
    System.out.println(conn);
    // 
    ComboPooledDataSource otherc3p0 = new ComboPooledDataSource("otherc3p0");
    Connection conn2 = otherc3p0.getConnection();
    System.out.println(conn2);
    conn2.close();


}

`

Druid를 사용하여 풀 연결

jar 패키지 가져오기

정의 프로필, 임의의 위치에 놓을 수 있음

     driverClassName=com.mysql.cj.jdbc.Driver
    url=jdbc:mysql://localhost:3306/db3?serverTimezone=UTC
    username=root
    password=root
    initialSize=5
    maxActive=10
    maxWait=3000

데이터베이스 연결 대상 획득, 공장 클래스를 통해 연결 대상connection 대상Druid

획득
`public class demo { private static Connection conn = null; private static PreparedStatement preparedStatement = null; private static ResultSet resultSet = null;

public static void main(String[] args) {
    ArrayList list = new ArrayList();
    try {
        // Connecttion
        conn = JDBCUtils.getConnection();
        String sql = "select * from account";
        preparedStatement = conn.prepareStatement(sql);
        resultSet = preparedStatement.executeQuery();
        while (resultSet.next()) {
            //System.out.println(resultSet.getString(1));
            list.add(new Person(resultSet.getInt(1), resultSet.getString(2), resultSet.getInt(3)));
        }
        JDBCUtils.close(resultSet, preparedStatement, conn);
        list.stream().forEach(name -> System.out.println(name));
    } catch (SQLException e) {
        e.printStackTrace();
    }

}
    }

`

DruidJDBCutils 정의

`public class JDBCUtils {
private static DataSource ds = null;

// 
static {
    Properties pro = new Properties();
    InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
    try {
        pro.load(is);
        ds = DruidDataSourceFactory.createDataSource(pro);
    } catch (IOException e) {
        e.printStackTrace();
    } catch (Exception e) {
        e.printStackTrace();
    }
}

// Connection 
public static Connection getConnection() throws SQLException {
    return ds.getConnection();
}
//  
public static void close(ResultSet resultSet, Statement stat, Connection conn) {
    if (resultSet != null) {
        try {
            resultSet.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    if (stat != null) {
        try {
            resultSet.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

public static void close(Statement stat, Connection conn) {
    close(null, stat, conn);
}
//  DataSource
public static DataSource getDataSource() {
    return ds == null ? ds : ds;
}

} `