db.java

连接数据库

import java.sql.*;


public class DB {
	public static Connection getConn()
	{
		Connection conn=null;
		try
		{
			Class.forName("com.mysql.jdbc.Driver");
			conn=DriverManager.getConnection("jdbc:mysql://localhost/bbs?user=root&password=root");
		}
		catch(ClassNotFoundException e)
		{
			e.printStackTrace();
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
		return conn;
	}
	
	public static Statement getStatement(Connection conn)
	{
		Statement st=null;
		try
		{
			if(conn!=null)
				st=conn.createStatement();
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
		return st;
	}
	
	public static ResultSet getResultSet(Statement st,String sql)
	{
		ResultSet rs=null;
		try
		{
			if(st!=null)
				rs=st.executeQuery(sql);
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
		return rs;
	}
	
	public static ResultSet getResultSet(Connection  conn,String sql)
	{
		ResultSet rs=null;
		Statement st=null;
		try
		{
			if(conn!=null)
			{
				st=conn.createStatement();
				rs=getResultSet(st,sql);
			}
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
		return rs;
	}
	
	public static void close(Connection conn)
	{
		try
		{
			if(conn!=null)
			{
				conn.close();
				conn=null;
			}
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
	}
	
	public static void close(Statement st)
	{
		try
		{
			if(st!=null)
			{
				st.close();
				st=null;
			}
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
	}
	
	public static void close(ResultSet rs)
	{
		try
		{
			if(rs!=null)
			{
				rs.close();
				rs=null;
			}
		}
		catch(SQLException e)
		{
			e.printStackTrace();
		}
	}
}