C3P0下载地址
https://mvnrepository.com/artifact/com.mchange/c3p0
C3P0数据库连接池
- 步骤
①导入jar包c3p0和mchange-commons-java不要忘记导入数据库驱动jar包
②定义配置文件c3p0.properties或者c3p0-config.xml,路径为src目录下
③创建核心对象CombopooledDataSource； DataSource dataSource = new ComboPooledDataSource();
④获取连接getDataSource - 配置文件c3p0-config.xml
<?xml version="1.0" encoding="utf-8"?>
<c3p0-config>
<default-config>
<!-- 连接参数-->
<property name="driverClass">com.mysql.cj.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/db4?&useSSL=false&serverTimezone=GMT</property>
<property name="user">root</property>
<property name="password">545267257zzt</property>
<!-- 连接池参数-->
<!-- 初始化申请的连接数-->
<property name="initialPoolSize">10</property>
<!-- 创建过的链接并使用后闲置下来的闲置时间,如果超过这个时间就会自动断开这个连接-->
<property name="maxIdleTime">30</property>
<!-- 最大连接数-->
<property name="maxPoolSize">20</property>
<!-- 最小连接数-->
<property name="minPoolSize">5</property>
<!-- 最多可以创建Statements对象的个数. . 就是可以执行baiSQL语句的对象的个数-->
<property name="maxStatements">200</property>
</default-config>
<named-config name="mysql">
<property name="driverClass">com.mysql.cj.jdbc.Driver</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/db4?&useSSL=false&serverTimezone=GMT</property>
<property name="user">root</property>
<property name="password">545267257zzt</property>
<property name="initialPoolSize">10</property>
<property name="maxIdleTime">30</property>
<property name="maxPoolSize">20</property>
<property name="minPoolSize">5</property>
<property name="maxStatements">200</property>
</named-config>
</c3p0-config>
import com.mchange.v2.c3p0.ComboPooledDataSource;
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.SQLException;
public class c3p0 {
public static void main(String[] args) throws SQLException {
//1.获取DataSource,使用默认配置
DataSource dataSource = new ComboPooledDataSource();
//使用配置文件中指定的配置信息，连接不同的数据库
//DataSource dataSource1 = new ComboPooledDataSource("mysql");
//2.获取连接
Connection connection = dataSource.getConnection();
//sql操作
//释放连接
connection.close();
}
}
Druid数据库连接池
- 步骤
- 导入druid-x.x.x.jar包
- 定义配置文件，是properties形式，可以叫任意名称，可以放置在任意路径下，手动加载
- 加载配置文件
ClassLoader classLoader = druid.class.getClassLoader();
URL resource = classLoader.getResource("druid.properties");
String string = resource.getPath();
properties.load(new FileReader(string)); - 获取数据源连接池对象：通过工厂类来获取DruidDataSourceFactory
- 获取连接getConnection；
- 配置文件druid.properties
driverClassname=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/db4?useSSL=false&serverTimezone=UTC
username=root
password=545267257zzt
#初始化连接数
initialSize=5
#最大连接数
maxActive=10
#最大等待时间
maxWait=3000
import javax.sql.DataSource;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.util.Properties;
public class druid {
public static void main(String[] args) throws Exception {
Properties properties = new Properties();
ClassLoader classLoader = druid.class.getClassLoader();
URL resource = classLoader.getResource("druid.properties");
String string = resource.getPath();
properties.load(new FileReader(string));
DataSource dataSource = DruidDataSourceFactory.createDataSource(properties);
Connection connection = dataSource.getConnection();
System.out.println(connection);
}
}
定义druid的工具类
- 定义一个类JDBCUtils
- 提供静态代码块加载配置文件，初始化连接池对象
- 提供方法
①获取连接的方法：通过数据库连接池获取连接
②释放资源
③获取连接池的方法
package it.heima.util;
import com.alibaba.druid.pool.DruidDataSourceFactory;
import javax.sql.DataSource;
import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
public class jdbcUtil {
// 1. 定义成员变量DataSource
private static DataSource ds;
static {
Properties properties = new Properties();
ClassLoader classLoader = jdbcUtil.class.getClassLoader();
URL resource = classLoader.getResource("druid.properties");
String path = resource.getPath();
try {
properties.load(new FileReader(path));
ds= DruidDataSourceFactory.createDataSource(properties);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
/*
*获取连接的方法
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
/*
*释放资源
*/
public static void close(Statement statement,Connection connection){
if (statement != null) {
try {
statement.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
public static void close(Statement statement, Connection connection, 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();
}
}
}
/*
获取连接池的方法
*/
public static DataSource getDataSource(){
return ds;
}
}
public class jdbcUtilTest {
public static void main(String[] args) {
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = jdbcUtil.getConnection();
String sql = "insert into student (id,name,cid) values (3, ?, 2)";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1,"zhangzetao");
preparedStatement.executeUpdate();
jdbcUtil.close(preparedStatement,connection);
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
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