DBCP usage

The configuration file ：

# connections setting up 
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=true
username=root
password=123456

# Initialize connection 
initialSize=10

# Maximum number of connections 
maxActive=50

# Maximum free connection 
maxIdle=20

# Minimum free connection 
minIdle=5

# Timeout wait time in milliseconds  6000 millisecond /1000 be equal to 60 second 
maxWait=60000
#JDBC The format of the connection attribute attribute attached to the driver when establishing the connection must be as follows ：【 Property name =property;】
# Be careful ：user  And  password  Two attributes are explicitly passed , So there's no need to include them .
connectionProperties=useUnicode=true;characterEncoding=UTF8

# Specifies the automatic commit of connections created by the connection pool （auto-commit） state .
defaultAutoCommit=true

#driver default  Specifies the read-only... Of the connection created by the connection pool （read-only） state .
# If the value is not set , be “setReadOnly” Method will not be called .（ Some drivers do not support read-only mode , Such as ：Informix）
defaultReadOnly=

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

Tool class extraction ：

package com.hyc.study05.utils;
import com.hyc.study02.utils.JDBCUtils;
import org.apache.commons.dbcp.BasicDataSourceFactory;
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;

public class DBCPUtils {
    
    public static DataSource dataSource = null;

    static {
    
        try {
    
            InputStream inputStream = JDBCUtils.class.getClassLoader().getResourceAsStream("dbcp.properties");
            Properties properties = new Properties();
            properties.load(inputStream);
            
            // create data source   Factory mode --> establish 
            dataSource = BasicDataSourceFactory.createDataSource(properties);
        } catch (Exception e) {
    
            e.printStackTrace();
        }
    }

    // Get the connection 
    public static Connection getConnection() throws SQLException {
    
        return dataSource.getConnection();// Get the connection from the data source 
    }

    // Release the connection 
    public static void release(Connection connection, Statement statement, ResultSet resultSet) {
    
        if (resultSet != null) {
    
            try {
    
                resultSet.close();
            } catch (SQLException throwables) {
    
                throwables.printStackTrace();
            }
        }
        if (statement != null) {
    
            try {
    
                statement.close();
            } catch (SQLException throwables) {
    
                throwables.printStackTrace();
            }
        }
        if (connection != null) {
    
            try {
    
                connection.close();
            } catch (SQLException throwables) {
    
                throwables.printStackTrace();
            }
        }
    }
}

It is mainly in obtaining database connection and simple use JDBC A little difference between , After using the database connection pool , You don't need to write code to connect to the database .（ Connection pool mainly implements DataSource Interface ）

test ：

package com.hyc.study05;
import com.hyc.study05.utils.DBCPUtils;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Date;

public class TestDBCP {
    
    public static void main(String[] args) {
    
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        try {
    
            //3、 Get database connection 
            connection = DBCPUtils.getConnection();
            // Use ？ Placeholders replace parameters 
            String sql = "INSERT INTO `users`(`id`,`NAME`,`PASSWORD`,`email`,`birthday`) " +
                    "VALUES (?,?,?,?,?);";
            //4、 Access to perform sql The object of 
            // precompile sql, First write sql, Then don't execute 
            preparedStatement = connection.prepareStatement(sql);
            // Assign parameters manually 
            preparedStatement.setInt(1, 4);
            preparedStatement.setString(2, "hyc");
            preparedStatement.setString(3, "123456");
            preparedStatement.setString(4, "[email protected]");
            //java.sql.Date  It's database Date , Only the date information is included  , It is java.util.Date（ Contains the information of month, day, hour, minute and second ） Subclasses of 
            preparedStatement.setDate(5, new java.sql.Date(new Date().getTime()));

            //5、 perform sql sentence 
            //6、 Return execution result set 
            int num = preparedStatement.executeUpdate();
            if (num > 0) {
    
                System.out.println(" Insert data succeeded ！");
            }

        } catch (SQLException throwables) {
    
            throwables.printStackTrace();
        } finally {
    
            //7、 Release the connection 
            DBCPUtils.release(connection, preparedStatement, resultSet);
        }
    }
}