Usage and usage instructions of JDBC connection pool

We all know through jdbc Link to Will consume a lot of connections , Every connection consumes resources , close 》 Opening it will consume resources , Build up... Frequently 、 Close the connection , It will greatly reduce the performance of the system , Because the use of connections becomes the bottleneck of system performance .

Advantages brought by database connection pool technology ：

1． Resource reuse

2． Faster system response time

3． New means of resource allocation

4． Unified connection management , Avoid database connection leaks

Principle diagram

Using process ：

jdbc.properties

DriverClass = com.mysql.jdbc.Driver
JdbcUrl = jdbc\:mysql\://ID\:3306/htmldata?useUnicode\=true&characterEncoding\=UTF-8
User = root
Password = 123
MaxPoolSize = 20
MinPoolSize = 2
InitialPoolSize = 5
MaxStatements = 30
MaxIdleTime =100

C3P0Mysql.java

package class_name;
import java.sql.Connection;
import java.util.Properties;
import com.mchange.v2.c3p0.ComboPooledDataSource;
public class C3P0Mysql {
	private ComboPooledDataSource cpds;
	private static C3P0Mysql c3P0Properties;
	static{
		c3P0Properties = new C3P0Mysql();
	}
	public C3P0Mysql() {
		try {
			cpds = new ComboPooledDataSource();
			
			// Load profile 
			Properties props = new Properties();
			props.load(C3P0Mysql.class.getClassLoader().getResourceAsStream("jdbc.properties"));
			cpds.setDriverClass(props.getProperty("DriverClass"));
			cpds.setJdbcUrl(props.getProperty("JdbcUrl"));
			cpds.setUser(props.getProperty("User"));
			cpds.setPassword(props.getProperty("Password"));
			cpds.setMaxPoolSize(Integer.parseInt(props.getProperty("MaxPoolSize")));
			cpds.setMinPoolSize(Integer.parseInt(props.getProperty("MinPoolSize")));
			cpds.setInitialPoolSize(Integer.parseInt(props.getProperty("InitialPoolSize")));
			cpds.setMaxStatements(Integer.parseInt(props.getProperty("MaxStatements")));
			cpds.setMaxIdleTime(Integer.parseInt(props.getProperty("MaxIdleTime")));
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	public static C3P0Mysql getInstance(){
		return c3P0Properties;
	}
	
	public Connection getConnection(){
		Connection conn = null;
		try {
			conn = cpds.getConnection();
		} catch (Exception e) {
			e.printStackTrace();
		}
		return conn;
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Connection connection = C3P0Mysql.c3P0Properties.getConnection();
		System.out.println(" Connected successfully ");
	}
}