C3p0 database connection pool usage

The configuration file ：（ Be careful ：c3p0 Of xml The profile name must be c3p0-config , Otherwise, null pointer will be reported ）

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <!--
    c3p0 Default （ Default ） To configure 
     If in code ComboPooledDataSource ds=new ComboPooledDataSource(); This means that you are using c3p0 Default （ Default ）
    -->
    <default-config>
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&amp;characterEncoding=utf8&amp;useSSL=true&amp;serverTimezone=UTC</property>
        <property name="user">root</property>
        <property name="password">123456</property>
        <property name="acquiredIncrement">5</property>
        <property name="initialPoolSize">10</property>
        <property name="minPoolSize">5</property>
        <property name="maxPoolSize">20</property>
    </default-config>

    <!--
    c3p0 Named configuration for 
     If in code ComboPooledDataSource ds=new ComboPooledDataSource("MySQL"); This means that you are using name yes MySQL
    -->
    <name-config name="MySQL">
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&amp;characterEncoding=utf8&amp;useSSL=true&amp;serverTimezone=UTC</property>
        <property name="user">root</property>
        <property name="password">123456</property>
        <property name="acquiredIncrement">5</property>
        <property name="initialPoolSize">10</property>
        <property name="minPoolSize">5</property>
        <property name="maxPoolSize">20</property>
    </name-config>
</c3p0-config>

Tool class extraction ：

package com.hyc.study06.utils;
import com.mchange.v2.c3p0.ComboPooledDataSource;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class C3P0Utils {
    
    public static DataSource dataSource = null;

    static {
    
        try {
    
            // Code configuration 
// dataSource = new ComboPooledDataSource();
// dataSource.setDriverClass();
// dataSource.setJdbcUrl();
// dataSource.setUser();
// dataSource.setPassword();
// dataSource.setMaxPoolSize();
// dataSource.setMinPoolSize();

            // Configuration file writing （XML The file does not need to be read , It will match automatically when loading ）
            dataSource = new ComboPooledDataSource("MySQL");
        } catch (Exception e) {
    
            e.printStackTrace();
        }
    }

    // Get the connection 
    public static Connection getConnection() throws SQLException {
    
        // Get the connection from the data source 
        return dataSource.getConnection();// And DBCP It's all implemented DataSource Interface 
    }

    // 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();
            }
        }
    }
}

test ：

package com.hyc.study06;
import com.hyc.study06.utils.C3P0Utils;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Date;

public class TestC3P0 {
    
    public static void main(String[] args) {
    
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;
        try {
    
            //3、 Get database connection 
            connection = C3P0Utils.getConnection();// It was realized by myself , Now it is realized by others 
            // 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, 5);
            preparedStatement.setString(2, "hhh");
            preparedStatement.setString(3, "1135656");
            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 
            C3P0Utils.release(connection, preparedStatement, resultSet);
        }
    }
}