// The main function is to connect and close the database
public class ConnectionBase
{
	private final String  DbDriver = "com.mysql.jdbc.Driver";//Load the driver. The address of the driver is in quotation marks
	private final String  URL = "jdbc:mysql://localhost:********";//Database connection address
	private final String  user = "****";  //Database name
	private final String  userPWD = "****";	//Database password
	private Connection conn = null ;
	

	public ConnectionBase(String URL){
		try
		{
			Class.forName(DbDriver) ;
			this.conn = DriverManager.getConnection(URL,user,userPWD) ;	
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
	}
	
	public ConnectionBase()
	{
		try
		{
			Class.forName(DbDriver) ;
			this.conn = DriverManager.getConnection(URL,user,userPWD) ;	
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
	}

	
	
	// Get database connection
	public Connection getConnection()
	{
		return this.conn ;
	}

	
	
	
	// Close database connection
	public void close()
	{
		try
		{
			this.conn.close() ;
		}
		catch (Exception e)
		{
		}		
	}	
};

DBCP creates database connection pool

There are two jar packages needed to create a connection pool using DBCP:
commons-pool-1.5.6.jar
commons-dbcp-1.4.jar

• Do not use configuration file (generally not used)

public void testDBCP01(){
		
			
			Connection conn = null;
			PreparedStatement ps = null;
			try {
				
				//1. Build data source object
				BasicDataSource dataSource = new BasicDataSource();
				//What kind of database is connected to, which database is accessed, user name, password..
				//jdbc:mysql://localhost/bank master protocol: sub protocol: / / local / database

				//In this part, a large number of set * * methods are used,
				dataSource.setDriverClassName("com.mysql.jdbc.Driver");
				dataSource.setUrl("jdbc:mysql://localhost: port / table name“);
				dataSource.setUsername("root");
				dataSource.setPassword("root");
				
				
				//2. Get connected objects
				conn = dataSource.getConnection();
				String sql = "insert into account values(null , ? , ?)";
				ps = conn.prepareStatement(sql);
				ps.setString(1, "admin");
				ps.setInt(2, 1000);
				
				ps.executeUpdate();
				
			} catch (SQLException e) {
				e.printStackTrace();
			}finally {
				JDBCUtil.release(conn, ps);
			}
			
		}

• Configuration file: dbcpconfig.properties
• Here is the contents of dbcpconfig.properties

#connections setting up
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306 / table
username=root
password=root

#
initialSize=10

#Maximum number of connections
maxActive=50

#
maxIdle=20

#
minIdle=5

#
maxWait=60000

#The format of the connection property property attached to the JDBC driver when establishing a connection must be as follows: [property name = property;]
#Note that the "user" and "password" attributes are explicitly passed, so they don't need to be included here.
connectionProperties=useUnicode=true;characterEncoding=gbk

#Specifies the auto commit state of the connection created by the connection pool.
defaultAutoCommit=true

#driver default specifies the transaction level (TransactionIsolation) of the connection created by the connection pool.
#The available values are one of the following: (see javadoc for details.) NONE,READ_UNCOMMITTED, READ_COMMITTED, REPEATABLE_READ, SERIALIZABLE
defaultTransactionIsolation=READ_UNCOMMITTED

• How to use profile (common)

Connection conn = null;
		PreparedStatement ps = null;
		try {
			BasicDataSourceFactory factory = new BasicDataSourceFactory();
			Properties properties = new Properties();
			//Creating database connection pool with file content
			InputStream is = new FileInputStream("src//dbcpconfig.properties");
			properties.load(is);
			DataSource dataSource = factory.createDataSource(properties);
			
			//2. Get connected objects
			conn = dataSource.getConnection();
			String sql = "insert into table values(null , ? , ?)";
			ps = conn.prepareStatement(sql);
			ps.setString(1, "Name");
			ps.setInt(2, 100);
			
			ps.executeUpdate();
			
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			JDBCUtil.release(conn, ps);
		}

CP30C create database connection pool

Next time!