1：第一种方式非常简单 c3p0.driverClass=com.mysql.jdbc.Driverc3p0.jdbcUrl=jdbc:mysql://localhost:3308/databasec3p0.user=rootc3p0.password=root 文件名字为：c3p0.properties（放在src目录下面） //程序我写的比较简单，可以用来测试执行配置。 packa

1：第一种方式非常简单

c3p0.driverClass=com.mysql.jdbc.Driver
c3p0.jdbcUrl=jdbc:mysql://localhost:3308/database
c3p0.user=root
c3p0.password=root

package jdbc.mysql;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3P0 {
	public static void main(String[] args) throws SQLException {
	//数据库连接池默认会到classpath下去找数据库的配置。
	ComboPooledDataSource data = new ComboPooledDataSource();
	Connection conn = data.getConnection();
	String sql = "select * from table";
	PreparedStatement pstmt = conn.prepareStatement(sql);
	ResultSet rs = pstmt.executeQuery();
	while(rs.next()){
	System.out.println(rs.getString(1));
	}
	}
}

 
 root
 1234
 com.mysql.jdbc.Driver
 jdbc:mysql://localhost:3306/database?characterEncoding=UTF-8&useOldAliasMetadataBehavior=true 
 2
 30
 100
 2
 
 
 
 root
 root
 com.mysql.jdbc.Driver
 jdbc:mysql://localhost:3308/database?characterEncoding=UTF-8&useOldAliasMetadataBehavior=true 
 2
 30
 100
 2
 

package jdbc.mysql;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.sql.DataSource;

import com.mchange.v2.c3p0.ComboPooledDataSource;

public class C3p0JDBC {
	public static void main(String[] args) throws SQLException {
	System.setProperty("com.mchange.v2.c3p0.cfg.xml",System.getProperty("user.dir")+"/config/c3p0-config.xml");
	//上面的配置文件  
	//默认情况下 构造函数传空值。会去找默认配置
	DataSource data = new ComboPooledDataSource();
	//上面的配置文件 
	//如果构造函数中传值，则找到对应的配置。
	DataSource data1 = new ComboPooledDataSource("database");
	Connection conn = data.getConnection();
	Connection conn1 = data1.getConnection();
	String sql = "select * from table";
	PreparedStatement pstmt = conn1.prepareStatement(sql);
	ResultSet rs = pstmt.executeQuery();
	while(rs.next()){
	System.out.println(rs.getString(1));
	}
	}
}

可选择性使用

import com.mchange.v2.c3p0.*;
........	
ComboPooledDataSource cpds = new ComboPooledDataSource();
cpds.setDriverClass( "org.postgresql.Driver" ); //loads the jdbc driver 
cpds.setJdbcUrl( "jdbc:postgresql://localhost/testdb" );
cpds.setUser("dbuser"); 
cpds.setPassword("dbpassword"); 

cpds.setMaxStatements( 180 ); 
cpds.close();