jdbc data source (DruidDataSourceFactory) connection pool – druid

 <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.28</version>
            <scope>compile</scope>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.2.16</version>
        </dependency>
    </dependencies>

1. Druid data source connection pool technology

package com.csdn.jdbc;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import java.sql.SQLException;
// Demonstrate data source connection pool druid Druid data source connection pool technology
public class DataSourceConnectPool {

    public static void main(String[] args) throws SQLException {

        DruidDataSource dataSource = new DruidDataSource();

        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql:///fruitdb");
        dataSource.setUsername("root");
        dataSource.setPassword("123456");

        dataSource.setInitialSize(5); //Initialization quantity
        dataSource.setMaxActive(10); //Maximum number of activations
        dataSource.setMaxWait(5000); //Maximum waiting time

        for (int count = 1; count <= 11; count + + ) {
            DruidPooledConnection conn = dataSource.getConnection();
            System.out.println(conn);
        }
    }
}
D:\Java\jdk-17\bin\java.exe com.csdn.jdbc.DataSourceConnectPool
October 27, 2023 12:51:59 PM com.alibaba.druid.pool.DruidDataSource info
Information: {dataSource-1} inited
com.mysql.cj.jdbc.ConnectionImpl@408d971b
com.mysql.cj.jdbc.ConnectionImpl@6c6cb480
com.mysql.cj.jdbc.ConnectionImpl@3c46e67a
com.mysql.cj.jdbc.ConnectionImpl@c730b35
com.mysql.cj.jdbc.ConnectionImpl@206a70ef
com.mysql.cj.jdbc.ConnectionImpl@292b08d6
com.mysql.cj.jdbc.ConnectionImpl@22555ebf
com.mysql.cj.jdbc.ConnectionImpl@36ebc363
com.mysql.cj.jdbc.ConnectionImpl@45752059
com.mysql.cj.jdbc.ConnectionImpl@34e9fd99
Exception in thread "main" com.alibaba.druid.pool.GetConnectionTimeoutException: wait millis 5003, active 10, maxActive 10, creating 0
at com.alibaba.druid.pool.DruidDataSource.getConnectionInternal(DruidDataSource.java:1840)
at com.alibaba.druid.pool.DruidDataSource.getConnectionDirect(DruidDataSource.java:1470)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1450)
at com.alibaba.druid.pool.DruidDataSource.getConnection(DruidDataSource.java:1440)
at com.csdn.jdbc.DataSourceConnectPool.main(DataSourceConnectPool.java:22)

Process finished with exit code 1

• The 10 connection objects obtained are all different, and the maximum number of activations is 10. If you want to obtain the 11th one, wait for 5 seconds, and the connection object will time out.

package com.csdn.jdbc;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import java.sql.SQLException;
// Demonstrate data source connection pool druid Druid data source connection pool technology
public class DataSourceConnectPool {

    public static void main(String[] args) throws SQLException {

        DruidDataSource dataSource = new DruidDataSource();

        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql:///fruitdb");
        dataSource.setUsername("root");
        dataSource.setPassword("123456");

        dataSource.setInitialSize(5); //Initialization quantity
        dataSource.setMaxActive(10); //Maximum number of activations
        dataSource.setMaxWait(5000); //Maximum waiting time

        for (int count = 1; count <= 11; count + + ) {
            DruidPooledConnection conn = dataSource.getConnection();
            System.out.println(conn);
            
            if (count % 4 == 0) {
                conn.close();
            }
            
        }
    }
}
D:\Java\jdk-17\bin\java.exe
October 27, 2023 12:57:41 PM com.alibaba.druid.pool.DruidDataSource info
Information: {dataSource-1} inited
com.mysql.cj.jdbc.ConnectionImpl@6c6cb480
com.mysql.cj.jdbc.ConnectionImpl@3c46e67a
com.mysql.cj.jdbc.ConnectionImpl@c730b35
com.mysql.cj.jdbc.ConnectionImpl@206a70ef
com.mysql.cj.jdbc.ConnectionImpl@206a70ef
com.mysql.cj.jdbc.ConnectionImpl@292b08d6
com.mysql.cj.jdbc.ConnectionImpl@22555ebf
com.mysql.cj.jdbc.ConnectionImpl@36ebc363
com.mysql.cj.jdbc.ConnectionImpl@36ebc363
com.mysql.cj.jdbc.ConnectionImpl@45752059
com.mysql.cj.jdbc.ConnectionImpl@34e9fd99

2. Data source connection pool, load jdbc.properties

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql:///fruitdb
jdbc.user=root
jdbc.pwd=123456
jdbc.initial_size=5
jdbc.max_active=10
jdbc.max_wait=5000

package com.csdn.jdbc;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.pool.DruidPooledConnection;
import java.io.IOException;
import java.io.InputStream;
import java.sql.SQLException;
import java.util.Properties;
//Demo data source connection pool loading jdbc.properties
public class DataSourceConnectPoolProperties {

    public static void main(String[] args) throws SQLException, IOException {

        InputStream inputStream = DataSourceConnectPoolProperties.class.getClassLoader().getResourceAsStream("jdbc.properties");
        Properties properties = new Properties();
        properties.load(inputStream);

        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(properties.getProperty("jdbc.driver"));
        dataSource.setUrl(properties.getProperty("jdbc.url"));
        dataSource.setUsername(properties.getProperty("jdbc.user"));
        dataSource.setPassword(properties.getProperty("jdbc.pwd"));

        dataSource.setInitialSize(Integer.parseInt(properties.getProperty("jdbc.initial_size"))); //Initialization quantity
        dataSource.setMaxActive(Integer.parseInt(properties.getProperty("jdbc.max_active"))); //Maximum number of activations
        dataSource.setMaxWait(Integer.parseInt(properties.getProperty("jdbc.max_wait"))); //Maximum waiting time

        for (int count = 1; count <= 11; count + + ) {
            DruidPooledConnection conn = dataSource.getConnection();
            System.out.println(conn);
            if (count % 4 == 0) {
                conn.close();
            }
        }
    }
}

3. Data source connection pool, load the upgraded version of jdbc.properties, the key is fixed and consistent with the properties in the connection pool factory

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql:///fruitdb
username=root
password=123456
initialSize=5
maxActive=10
maxWait=1000

package com.csdn.jdbc;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.util.Properties;
//Demonstrate data source connection pool. Load jdbc.properties. The key is fixed and consistent with the properties in the connection pool factory.
public class DataSourceConnectPoolPropertiesFactory {

    public static void main(String[] args) throws Exception {

        InputStream inputStream = DataSourceConnectPoolPropertiesFactory.class.getClassLoader().getResourceAsStream("jdbc2.properties");
        Properties properties = new Properties();
        properties.load(inputStream);

        DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);

        for (int count = 1; count <= 11; count + + ) {
            Connection conn = dataSource.getConnection();
            System.out.println(conn);
            if (count % 4 == 0) {
                conn.close();
            }
        }
    }
}

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