uso del grupo de conexiones java-c3p0

c3p0 conecta mysql xml y el paquete jar para recibirlo tú mismo

Enlace: https://pan.baidu.com/s/1HYoQsDdtGENskfIOQhEbUA Código de extracción: i4nj

package entity;

/**
 * 实体类
 * 
 * @author 小虎牙
 *
 */

public class user {
/**
 * 这里的名字和数据库里面的名字必须一样，要有默认的构造函数
 */
	private String name;
	private String username;
	private String password;

	public user() {
		// TODO 自动生成的构造函数存根
	}

	@Override
	public String toString() {
		return "user [name=" + name + ", username=" + username + ", password=" + password + "]";
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getusername() {
		return username;
	}

	public void setusername(String username) {
		this.username = username;
	}

	public String getpassword() {
		return password;
	}

	public void setpassword(String password) {
		this.password = password;
	}

}

package util;
/**
 * 工具类
 */
import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class JDBCUtil {
	private static DataSource dataSourse;// 数据源的配置，相当于池子

	public static void setDataSourse(DataSource dataSourse) {
		JDBCUtil.dataSourse = dataSourse;
	}

	static {
		dataSourse = new ComboPooledDataSource();
	}

	public static DataSource getDataSourse() {
		return dataSourse;
	}
}

import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import entity.user;
import util.JDBCUtil;

public class main_dao {
private static QueryRunner runner=new QueryRunner(JDBCUtil.getDataSourse());
public static void main(String[] args) {
	try {
		//增删改
		runner.update("delete from user where name ='002';");
		//查寻一个放到类
		user u1=runner.query("select * from user where name =?",  new BeanHandler<>(user.class),"张三");
		System.out.println(u1);
		System.out.println("--------------------");
		//查询多个
		List<user> list=runner.query("select * from user ",  new BeanListHandler<>(user.class));
		Iterator<user> iterator=list.iterator();
		while (iterator.hasNext()) {
			System.out.println(iterator.next());
		}
		
		} catch (SQLException e) {
		// TODO 自动生成的 catch 块
		e.printStackTrace();
	}
}
}

Este es el archivo xml ubicado en la carpeta src

<?xml version="1.0" encoding="UTF-8"?>

<c3p0-config>
	<!-- C3P0的缺省(默认)配置， 如果在代码中“ComboPooledDataSource ds = new ComboPooledDataSource();”这样写就表示使用的是C3P0的缺省(默认)配置信息来创建数据源 -->
	<default-config>
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/java</property>
		<property name="user">root</property>
		<property name="password">root</property>

		<property name="acquireIncrement">5</property>
		<property name="initialPoolSize">10</property>
		<property name="minPoolSize">5</property>
		<property name="maxPoolSize">20</property>
	</default-config>

	<!-- C3P0的命名配置， 如果在代码中“ComboPooledDataSource ds = new ComboPooledDataSource("MySQL");”这样写就表示使用的是name是MySQL的配置信息来创建数据源 -->
	<named-config name="MySQL">
		<property name="driverClass">com.mysql.jdbc.Driver</property>
		<property name="jdbcUrl">jdbc:mysql://localhost:3306/java</property>
		<property name="user">root</property>
		<property name="password">root</property>

		<property name="acquireIncrement">5</property>
		<property name="initialPoolSize">10</property>
		<property name="minPoolSize">5</property>
		<property name="maxPoolSize">20</property>
	</named-config>

</c3p0-config>