Java JDBC篇4——数据库连接池

1、DBCP

1.1、依赖jar包

官网：https://mvnrepository.com/artifact/org.apache.commons/commons-dbcp2

mysql-connector-java-5.1.49.jar 百度云：https://pan.baidu.com/s/17J2VfkGS2h44j69eB8TuFA提取码：nhnt

mysql-connector-java-8.0.25.jar 百度云：https://pan.baidu.com/s/1b8n7650uMKJtwidoptOjNQ提取码：wtvn

commons-dbcp2-2.8.0 百度云：https://pan.baidu.com/s/10bcq3Fzo36MnFFMppICi3A提取码：1tkz

commons-pool2-2.8.0 百度云：https://pan.baidu.com/s/1sZLSi0nRZqeYbhDuO5Mkxw提取码：hk3w

commons-logging-1.2 百度云：https://pan.baidu.com/s/1ZFZZcmCjZtRwumh_qisKIw提取码：2uaz

1.2、快速入门

url=jdbc:mysql://localhost:3306/test
user=root
password=blingbling123.
driver=com.mysql.jdbc.Driver

public class DBCPPoolUtils {private static String urls;private static String user;private static String password;private static String driver;private static BasicDataSource basicDataSource=null;static {Properties properties=new Properties();ClassLoader classLoader=JDBCtool.class.getClassLoader();URL url=classLoader.getResource("connection.properties");String path=url.getPath();try {properties.load(new FileReader(path));} catch (IOException e) {e.printStackTrace();}System.out.println(properties);basicDataSource=new BasicDataSource();basicDataSource.setDriverClassName(properties.getProperty("driver"));basicDataSource.setUrl(properties.getProperty("url"));basicDataSource.setUsername(properties.getProperty("user"));basicDataSource.setPassword(properties.getProperty("password"));}public static Connection getConnection() throws SQLException {System.out.println(basicDataSource);//从连接池中获取连接Connection connection = basicDataSource.getConnection();return connection;}public static void close(Connection connection, Statement statement, ResultSet resultSet){if (resultSet!=null){try {resultSet.close();} catch (SQLException e) {e.printStackTrace();}}if (statement!=null){try {statement.close();} catch (SQLException e) {e.printStackTrace();}}if (connection!=null){try {connection.close();} catch (SQLException e) {e.printStackTrace();}}}
}

public class Test {public static void main(String[] args) throws SQLException {Connection connection = DBCPPoolUtils.getConnection();String sql="select * from user";PreparedStatement preparedStatement = connection.prepareStatement(sql);ResultSet resultSet = preparedStatement.executeQuery();while (resultSet.next()){System.out.println(resultSet.getString("username"));}DBCPPoolUtils.close(connection,preparedStatement,resultSet);}
}

1.3、配置项

属性	描述
driverClassName	数据库驱动名称
url	数据库地址
username	用户名
password	密码
maxActive	最大连接数量
maxIdle	最大空闲连接
minIdle	最小空闲连接
initialSize	初始化连接

2、Druid

2.1、依赖jar包

官网：https://mvnrepository.com/artifact/com.alibaba/druid

mysql-connector-java-5.1.49.jar 百度云：https://pan.baidu.com/s/17J2VfkGS2h44j69eB8TuFA提取码：nhnt

mysql-connector-java-8.0.25.jar 百度云：https://pan.baidu.com/s/1b8n7650uMKJtwidoptOjNQ提取码：wtvn

druid1.2.6 百度云：https://pan.baidu.com/s/1f90LwWhAtPaAOASKf1UfPA提取码：iq2n

2.2、快速入门

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/test
username=root
password=blingbling123.
initialSize=5
maxActive=10
maxWait=3000

public class DruidPoolUtils {private static DataSource dataSource=null;static {Properties properties=new Properties();ClassLoader classLoader=JDBCtool.class.getClassLoader();URL url=classLoader.getResource("connection.properties");String path=url.getPath();try {properties.load(new FileReader(path));System.out.println(properties);dataSource= DruidDataSourceFactory.createDataSource(properties);} catch (IOException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}}public static Connection getConnection(){try {return dataSource.getConnection();} catch (SQLException e) {e.printStackTrace();return null;}}public static void close(Connection connection, Statement statement, ResultSet resultSet){if (resultSet!=null){try {resultSet.close();} catch (SQLException e) {e.printStackTrace();}}if (statement!=null){try {statement.close();} catch (SQLException e) {e.printStackTrace();}}if (connection!=null){try {connection.close();} catch (SQLException e) {e.printStackTrace();}}}
}

public class Test {public static void main(String[] args) throws SQLException {Connection connection = DruidPoolUtils.getConnection();String sql="select * from user";PreparedStatement preparedStatement = connection.prepareStatement(sql);ResultSet resultSet = preparedStatement.executeQuery();while (resultSet.next()){System.out.println(resultSet.getString("username"));}DruidPoolUtils.close(connection,preparedStatement,resultSet);}
}