Java获取c3p0连接池

• 引入依赖

pom.xml 注意导的包 c3p0 有两个包(都要有)

 <dependencies>
        <dependency>
            <groupId>com.mchange</groupId>
            <artifactId>c3p0</artifactId>
            <version>0.9.5.5</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
        </dependency>

01.第一种方式:（不要配置文件）

 public static  void main(String[] args) throws SQLException, PropertyVetoException {
        ComboPooledDataSource sc=new ComboPooledDataSource();
        sc.setDriverClass("com.mysql.jdbc.Driver");
        sc.setJdbcUrl("jdbc:mysql://localhost:3306/test");
        sc.setUser("root");
        sc.setPassword("root");
        sc.setInitialPoolSize(10);
        Connection conn=sc.getConnection();
        System.out.println(conn);
    }

02.第二种方式(通过配置文件)

01.配置文件名 c3p0-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
    <named-config name="hellc3p0">
        <!-- 提供获取连接的4个基本信息 -->
        <property name="driverClass">com.mysql.jdbc.Driver</property>
        <property name="jdbcUrl">jdbc:mysql:///test</property>
        <property name="user">root</property>
        <property name="password">root</property>

        <!-- 进行数据库连接池管理的基本信息 -->
        <!-- 当数据库连接池中的连接数不够时，c3p0一次性向数据库服务器申请的连接数 -->
        <property name="acquireIncrement">5</property>
        <!-- c3p0数据库连接池中初始化时的连接数 -->
        <property name="initialPoolSize">10</property>
        <!-- c3p0数据库连接池维护的最少连接数 -->
        <property name="minPoolSize">10</property>
        <!-- c3p0数据库连接池维护的最多的连接数 -->
        <property name="maxPoolSize">100</property>
        <!-- c3p0数据库连接池最多维护的Statement的个数 -->
        <property name="maxStatements">50</property>
        <!-- 每个连接中可以最多使用的Statement的个数 -->
        <property name="maxStatementsPerConnection">2</property>

    </named-config>
</c3p0-config>

02.java测试代码

public static  void main(String[] args) throws SQLException {
        ComboPooledDataSource sc=new ComboPooledDataSource("hellc3p0");
        Connection conn=sc.getConnection();
        System.out.println(conn);
    }

03.第三种方式配置类

01.配置类

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.beans.PropertyVetoException;

@Configuration
public class SpringConf {

    @Bean
    public ComboPooledDataSource user02() throws PropertyVetoException {
        ComboPooledDataSource sc=new ComboPooledDataSource();
        sc.setJdbcUrl("jdbc:mysql://216.127.*.*:3166/mall_pms?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false");
        sc.setDriverClass("com.mysql.cj.jdbc.Driver");
        sc.setUser("root");
        sc.setPassword("root");
        sc.setInitialPoolSize(10);
        return sc;
    }

}

02.测试

@SpringBootTest
class DemoestApplicationTests {

    @Autowired
    SpringConf springConf;

    @Test
    void contextLoads() throws PropertyVetoException, SQLException {
        ComboPooledDataSource comboPooledDataSource = springConf.user02();
        Connection connection = comboPooledDataSource.getConnection();
        System.err.println("---"+connection);

        System.err.println(springConf.user02());


        PreparedStatement preparedStatement = connection.prepareStatement("select * from pms_brand where brand_id=1");

        ResultSet resultSet = preparedStatement.executeQuery(
        );
        while (resultSet.next()){
            System.err.println(resultSet.getString(2));
        }
    }
}