package com.trisun.util;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import javax.sql.DataSource;

import org.apache.commons.dbcp.BasicDataSourceFactory;

/**
 * @author tgl 
 * jdbc连接
 */
public class JdbcUtils {

	private static DataSource myDataSource = null;

	private JdbcUtils() {
		// 因为无须被构造，设为私有
	}

	static {// 设为static，使它只注册一次
		try {
			Properties prop = new Properties();
			InputStream is = JdbcUtils.class.getClassLoader().getResourceAsStream("dbcpconfig.properties");
			prop.load(is);
			myDataSource = BasicDataSourceFactory.createDataSource(prop);
		} catch (Exception e) {
			e.printStackTrace();
			throw new ExceptionInInitializerError(e);
		}
	}

	public static DataSource getDataSource() {
		return myDataSource;
	}

	public static Connection getConnection() throws SQLException {
		return myDataSource.getConnection();// 用连接池建立连接
	}

	public static void free(ResultSet rs, Statement st, Connection conn) {
		try {
			if (rs != null) rs.close();
		} catch (SQLException e) {
			e.printStackTrace();
		} finally {// finally保证无论抛出什么异常，finally里面包含的代码都会被执行
			try {
				if (st != null) st.close();
			} catch (SQLException e) {
				e.printStackTrace();
			} finally {
				try {
					if (conn != null) conn.close();
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
	}
}