C3P0数据库链接工具的使用

素颜马尾好姑娘i 2021-12-16 00:53 209阅读 0赞

*  jar包

![jar包][jar]

*  说明

使用C3P0包中的类来创建链接

ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
    				comboPooledDataSource.setDriverClass(driver);
    				comboPooledDataSource.setJdbcUrl(url);
    				comboPooledDataSource.setUser(user);
    				comboPooledDataSource.setPassword(password);
    				
    				//设置初始连接池中链接对象数量
    				comboPooledDataSource.setInitialPoolSize(5);
    				//设置最大连接池中的链接对象数量
    				comboPooledDataSource.setMaxPoolSize(10);
    				//设置最小连接池中空闲链接对象的数量
    				comboPooledDataSource.setMinPoolSize(2);

*  应用源码

package cn.wf.mysql;
    
    import java.beans.PropertyVetoException;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.util.ArrayList;
    
    import com.mchange.v2.c3p0.ComboPooledDataSource;
    
    
    /** * JAVA通过C3P0连接MySQL数据库 * @author WF * */
    
    public class JDBCMySQL_c3p0 { 
    
    	public static void main(String[] args) { 
    		//声明
    		Connection con = null;
    		//结果集
    		ResultSet rs = null;
    		String driver = "com.mysql.jdbc.Driver";
    		String url = "jdbc:mysql://localhost:3306/world";
    		String user = "root";
    		String password = "";
    		
    		ComboPooledDataSource comboPooledDataSource = new ComboPooledDataSource();
    		try { 
    				comboPooledDataSource.setDriverClass(driver);
    				comboPooledDataSource.setJdbcUrl(url);
    				comboPooledDataSource.setUser(user);
    				comboPooledDataSource.setPassword(password);
    				
    				//设置初始连接池中链接对象数量
    				comboPooledDataSource.setInitialPoolSize(5);
    				//设置最大连接池中的链接对象数量
    				comboPooledDataSource.setMaxPoolSize(10);
    				//设置最小连接池中空闲链接对象的数量
    				comboPooledDataSource.setMinPoolSize(2);
    				
    				con = comboPooledDataSource.getConnection();
    				//建立语句对象
    				String sql = "SELECT * FROM city";
    				PreparedStatement preparedStatement = con.prepareStatement(sql);
    				rs = preparedStatement.executeQuery(sql);
    				
    				String Name = null;
    				String CountryCode = null;
    				String District = null;
    				String Population = null;
    				
    				while (rs.next()) { 
    					Name = rs.getString("Name"); 
    					CountryCode = rs.getString("CountryCode");
    					District = rs.getString("District");
    					Population = rs.getString("Population");
    					System.out.println(Name+"\t"+CountryCode+"\t"+District+"\t"+Population);
    				}
    			} catch (PropertyVetoException e) { 
    				e.printStackTrace();
    			} catch (SQLException e) { 
    				e.printStackTrace();
    			}
    			
    
    				
    
    	}
    
    }

[jar]: /images/20211215/037a507caceb443da6439254190fffe3.png