databasetool.java

具备留言的功能

package j2ee.pj.db;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DataBaseTool {
	private Connection conn;
	private Statement stm;
	private static DataBaseTool dbt=new DataBaseTool();
	public DataBaseTool(){}
	public static DataBaseTool getDataBaseTool(){
		return dbt;
	}
	public Connection getConnection(){
		try {
			Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
			conn=DriverManager.getConnection("jdbc:sqlserver://127.0.0.1:1433;DatabaseName=SayingDB","sa","");
			return conn;
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			
		}
		return null;
	}
	public void closeConnection(){
		try {
				if(stm!=null){
					stm.close();
					stm=null;
				}
				if(conn!=null){
					conn.close();
					conn=null;
				}
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		
	}
	public boolean insertAndUpdateAndDelete(String sql){
		if(conn==null){
			this.getConnection();
		}
		try {
			stm=conn.createStatement();
			stm.executeUpdate(sql);
			return true;
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return false;
		}
	}
	public ResultSet query(String sql){
		if(conn==null){
			this.getConnection();
		}
		try {
			stm=conn.createStatement();
			ResultSet rs=stm.executeQuery(sql);
			return rs;
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
		
	}
}