JDBC公共操作类详解编程语言

import java.sql.Connection; 
import java.sql.DriverManager; 
import java.sql.ResultSet; 
import java.sql.SQLException; 
import java.sql.Statement; 
 
public class DBUtil { 
	public static final String DRIVER = "com.mysql.jdbc.Driver"; 
	public static final String URL = "jdbc:mysql://localhost:3306/db"; 
	public static final String USERNAME = "root"; 
	public static final String PASSWORD = "root"; 
 
	/** 
	 * 通过静态代码块 注册数据库驱动 
	 */ 
	static { 
		try { 
			Class.forName(DRIVER); 
		} catch (ClassNotFoundException e) { 
			e.printStackTrace(); 
		} 
	} 
 
	/** 
	 * 获得Connection 
	 *  
	 * @return 
	 */ 
	public static Connection getConnection() { 
		Connection conn = null; 
		try { 
			conn = DriverManager.getConnection(URL, USERNAME, PASSWORD); 
		} catch (SQLException e) { 
			e.printStackTrace(); 
		} 
		return conn; 
	} 
 
	/** 
	 * 获得Statement 
	 *  
	 * @return 
	 */ 
	public static Statement getStatement() { 
		Statement st = null; 
		try { 
			st = getConnection().createStatement(); 
		} catch (SQLException e) { 
			e.printStackTrace(); 
		} 
		return st; 
	} 
 
	/** 
	 * 关闭ResultSet 
	 *  
	 * @param rs 
	 */ 
	public static void closeResultSet(ResultSet rs) { 
		if (rs != null) { 
			try { 
				rs.close(); 
			} catch (SQLException e) { 
				e.printStackTrace(); 
			} 
		} 
	} 
 
	/** 
	 * 关闭Statement 
	 *  
	 * @param st 
	 */ 
	public static void closeStatement(Statement st) { 
		if (st != null) { 
			try { 
				st.close(); 
			} catch (SQLException e) { 
				e.printStackTrace(); 
			} 
		} 
	} 
 
	/** 
	 * 关闭Connection 
	 *  
	 * @param conn 
	 */ 
	public static void closeConnection(Connection conn) { 
		if (conn != null) { 
			try { 
				conn.close(); 
			} catch (SQLException e) { 
				e.printStackTrace(); 
			} 
		} 
	} 
 
	/** 
	 * 关闭全部 
	 *  
	 * @param rs 
	 * @param sta 
	 * @param conn 
	 */ 
	public static void closeAll(ResultSet rs, Statement sta, Connection conn) { 
		closeResultSet(rs); 
		closeStatement(sta); 
		closeConnection(conn); 
	} 
 
	/** 
	 * 获得总记录数 
	 *  
	 * @return 
	 */ 
	public static int getRows() { 
		int rows = 0; 
		Statement sta = null; 
		ResultSet rs = null; 
		Connection conn = getConnection(); 
		try { 
			sta = conn.createStatement(); 
			rs = sta.executeQuery("select * from e_user"); 
			rs.last(); 
			rows = rs.getRow(); 
		} catch (SQLException e) { 
			e.printStackTrace(); 
		} 
		return rows; 
 
	} 
}