MySql帮助类

import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mchange.v2.c3p0.ComboPooledDataSource;

public class JDBCUtils {
    //private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
    static ComboPooledDataSource dataSource = new ComboPooledDataSource();
    //静态代码块自动装载，连接数据库的参数
    static {

        try {
            dataSource.setDriverClass("com.mysql.cj.jdbc.Driver");
            dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC");
            dataSource.setUser("root");
            dataSource.setPassword("root");
            dataSource.setMaxPoolSize(10);//最大连接数
            dataSource.setMinPoolSize(0);//最小连接数
            dataSource.setInitialPoolSize(5);//初始化连接数
            dataSource.setAcquireIncrement(5);//连接增量
        } catch (PropertyVetoException e) {
            e.printStackTrace();
        }

    }
    //获得连接
    public static Connection getCon() {
        try {
            return dataSource.getConnection();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    public static ComboPooledDataSource getDataSource() {
        return dataSource;
    }
    //关闭连接
    public static void closeCon(Connection conn,PreparedStatement pst,ResultSet rs) {
        if(rs != null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            finally {rs = null;}
        }
        if(pst != null) {
            try {
                pst.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            finally {pst = null;}
        }
        if(conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            finally {conn = null;}
        }
    }
    public void closeCon(Connection conn) {
        if(conn != null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
            finally {conn = null;}
        }
    }
}