简单的JdbcUtil例子

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

public class JdbcUtil {
	private static String driverClassName;
	private static String url;
	private static String username;
	private static String password;
	
	static {
		//为上面值赋予参数
		try {
			
			InputStream in=JdbcUtil.class.getClassLoader().getResourceAsStream("dbcfg.properties");
			Properties properties=new Properties();
			properties.load(in);
			driverClassName=properties.getProperty("driverClassName");
			url=properties.getProperty("url");
			username=properties.getProperty("username");
			password=properties.getProperty("password");
			Class.forName(driverClassName);
			
		} catch (Exception e) {
			throw new RuntimeException();
		}
	}
	//获得连接
	public  static Connection getConnection() throws Exception{
		return DriverManager.getConnection(url, username, password);
	}
	//释放资源
	public static void release(ResultSet rs,Statement st,Connection conn){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				
			}
			rs=null;
		}
		if(st!=null){
			try {
				st.close();
			} catch (SQLException e) {
				
			}
			st=null;
		}
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				
			}
			conn=null;
		}
	}

}

用于读取配置文件中的连接。