开源数据库连接池的使用及其工具类_datasourceutils怎么导入

目录

C3P0数据库连接池的使用步骤

C3P0数据库连接池实例演示(包含配置信息)

Druid数据库连接池的使用步骤

Druid数据库连接池实例演示(包含配置信息)

连接池的工具类

C3P0数据库连接池的使用步骤

C3P0数据库连接池实例演示(包含配置信息)

<c3p0-config>
  <!-- 使用默认的配置读取连接池对象 -->
  <default-config>
  	<!--  连接参数 -->
    <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/dp1</property>
    <property name="user">root</property>
    <property name="password">123456</property>
    
    <!-- 连接池参数 -->
    <!-- 初始连接数 -->
    <property name="initialPoolSize">5</property>
    <!-- 最大连接数 -->
    <property name="maxPoolSize">10</property>
    <!-- 最大等待时间 -->
    <property name="checkoutTimeout">3000</property>
  </default-config>
 
<!-- 创建对象传参为otherc3p0时读取下面的配置信息 -->
  <named-config name="otherc3p0"> 
    <!--  连接参数 -->
    <property name="driverClass">com.mysql.cj.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/dp1</property>
    <property name="user">root</property>
    <property name="password">123456</property>
    
    <!-- 连接池参数 -->
    <property name="initialPoolSize">5</property>
    <property name="maxPoolSize">8</property>
    <property name="checkoutTimeout">1000</property>
  </named-config>
</c3p0-config>

package demo02.c3p0demo;
 
import com.mchange.v2.c3p0.ComboPooledDataSource;
 
import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
 
public class c3p0Test1 {
    public static void main(String[] args) throws Exception{
        //1.创建c3p0的数据库连接池对象
        DataSource dataSource = new ComboPooledDataSource();
        //2.通过连接池对象获取数据库连接
        Connection con = dataSource.getConnection();
        //3.查询学生表的全部信息
        String sql = "SELECT * FROM student";
        PreparedStatement pst = con.prepareStatement(sql);
        //4.执行sql语句,接收结果集
        ResultSet rs = pst.executeQuery();
        //5.处理结果集
        while(rs.next()){
            System.out.println(rs.getInt("sid")+"\t"+rs.getString("name")+"\t"+rs.getInt("age")+"\t"+rs.getDate("birthday"));
        }
        //6.释放资源
        rs.close();
        pst.close();
        con.close();//用完以后，进行归还
    }
}

Druid数据库连接池的使用步骤

Druid数据库连接池实例演示(包含配置信息)

driverClassName=com.mysql.cj.jdbc.Driver
url=jdbc:mysql://localhost:3306/dp1
username=root
password=123456
initialSize=5
maxActive=10
maxWait=3000

package demo02.druiddemo;
 
import com.alibaba.druid.pool.DruidDataSourceFactory;
 
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Properties;
 
public class druidTest {
    public static void main(String[] args) throws Exception{
        //获取配置文件的流对象
        InputStream is = druidTest.class.getClassLoader().getResourceAsStream("druid.properties");
        //1.通过Properties集合加载配置文件
        Properties prop = new Properties();
        prop.load(is);
        //2.通过Druid连接池工厂类获取数据库连接池对象
        DataSource dataSource = DruidDataSourceFactory.createDataSource(prop);
        //3.通过连接池对象获取数据库连接进行使用
        Connection con = dataSource.getConnection();
        //4.查询学生表的全部信息
        String sql = "SELECT * FROM student";
        PreparedStatement pst = con.prepareStatement(sql);
        //5.执行sql语句,接收结果集
        ResultSet rs = pst.executeQuery();
        //6.处理结果集
        while(rs.next()){
            System.out.println(rs.getInt("sid")+"\t"+rs.getString("name")+"\t"+rs.getInt("age")+"\t"+rs.getDate("birthday"));
        }
        //6.释放资源
        rs.close();
        pst.close();
        con.close();//用完以后，进行归还
    }
}

连接池的工具类

package demo02.utils;
 
import com.alibaba.druid.pool.DruidDataSourceFactory;
 
import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
 
public class DataSourceUtils {
    //1.私有构造方法
    private DataSourceUtils(){}
    //2.声明数据源变量
    private static DataSource dataSource;
    //3.提供静态代码块，完成配置文件的加载
    static{
        try {
            //完成配置文件的加载
            InputStream is = DataSourceUtils.class.getClassLoader().getResourceAsStream("druid.properties");
            Properties prop = new Properties();
            prop.load(is);
            //获取数据库连接池对象
            dataSource = DruidDataSourceFactory.createDataSource(prop);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    //4.提供一个获取数据库连接的方法
    public static Connection getConnection(){
        Connection con = null;
        try {
            con = dataSource.getConnection();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return con;
    }
    //5.提供一个获取数据库连接池对象的方法
    public static DataSource getDataSource(){
        return dataSource;
    }
    //6.释放资源
    public static void close(Connection con, Statement stat, ResultSet rs) {
        if(con != null) {
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
 
        if(stat != null) {
            try {
                stat.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
 
        if(rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
 
    public static void close(Connection con, Statement stat) {
        if(con != null) {
            try {
                con.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
 
        if(stat != null) {
            try {
                stat.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

package demo02.druiddemo;
 
import demo02.utils.DataSourceUtils;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
 
public class druidTest2 {
    public static void main(String[] args) throws Exception{
        //1.通过连接池工具类获取一个数据库连接
        Connection con = DataSourceUtils.getConnection();
        //2.查询学生表的全部信息
        String sql = "SELECT * FROM student";
        PreparedStatement pst = con.prepareStatement(sql);
        //3.执行sql语句,接收结果集
        ResultSet rs = pst.executeQuery();
        //4.处理结果集
        while(rs.next()){
            System.out.println(rs.getInt("sid")+"\t"+rs.getString("name")+"\t"+rs.getInt("age")+"\t"+rs.getDate("birthday"));
        }
        //5.释放资源
        DataSourceUtils.close(con,pst,rs);
    }
}