link_db.java

用JSP做的一个整站社区源码 用JSP做的一个整站社区源码

package useBean;

import java.sql.*;

public class Link_db{
	
	private static Connection con=null;
	private Statement state=null;
	private ResultSet rs=null;
	
	/***************************************************
		*method name:	init()<br>
		*method function:	Set up DataBase Statement<br>
		*return value:	void<br>
		*method function:	no<br>
		*amend:	crazyadept<br>
		*		2004/8/2<br>
	****************************************************/
	public void init(Connection con){
		try{
			state=Link_db.con.createStatement();
		}catch(Exception e){
			System.out.println("init");
			System.out.println(e.getMessage());
		}
	}
	
	/***************************************************
		*method name:	close()<br>
		*method function:	close DataBase Connection<br>
		*return value: 	void<br>
		*method function:	no<br>
		*amend:	crazyadept<br>
		*		2004/7/28<br>
	****************************************************/
	public void close(){
		try{
			if (rs !=null){
				rs.close();
				rs=null;
			}
		}catch(Exception e){
			System.out.println("rs");
			System.out.println(e.getMessage());
		}
		try{
			if(state!=null){
				state.close();
				state=null;
			}
		}catch(Exception e){
			System.out.println("state");
			System.out.println(e.getMessage());
		}
		try{
			if(con!=null){
				con.close();
				state=null;
			}
		}catch(Exception e){
			System.out.println("close");
			System.out.println(e.getMessage());
		}
	}
	
	/***************************************************
		*method name:	select()<br>
		*method function:	select DataBase data<br>
		*return value:  int<br>
		*		   	k=-10;	on word<br>
		*		   	k=0;	on record<br>
		*		   	k=-1;	have exception <br>
		*		   	k>0;	it is ok<br>
		*parameter explain:	no<br>
		*amend:	crazyadept<br>
		*		2004/8/2<br>
	****************************************************/
	public int select(String sql){
		int k=-10;
		this.init(Link_db.getCon());
		try{
			k=0;
			rs=state.executeQuery(sql);
			if(rs.next()){
				k=k+1;
			}
		}catch(Exception e){
			k=-1;
			System.out.println("select");
			System.out.println(e.getMessage());
			this.close();
		}
		this.close();
		return k;
	}
	
	/***************************************************
	*method name:	update()<br>
	*method function:	updata,insert,delete<br>
	*return value:  int<br>
	*		   	k=-10;	on work	<br>
	*		   	k=0;	on insert data<br>
	*		   	k=-1;	hava exception<br>
	*		   	k>0; 	work is ok<br>
	*parameter explain:	no<br>
	*amend:	crazyadept<br>
	*		2004/8/2<br>
	****************************************************/
	public int update(String sql){
		int k=-10;
		this.init(Link_db.getCon());
		try{
			k=0;
			k=state.executeUpdate(sql);
		}catch(Exception e){
			k=-1;
			System.out.println("update");
			System.out.println(e.getMessage());
		}
		this.close();
		return k;
	}

	/***************************************************
	*method name:	getCon()<br>
	*method function:	get DataBase Connection<br>
	*return value:  Connection<br>
	*		   		con; return DataBase Connection<br>
	*parameter explain:	no<br>
	*amend:	crazyadept<br>
	*		2004/8/2
	****************************************************/
	public static synchronized Connection getCon(){
		try{
			Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
			con=DriverManager.getConnection("jdbc:odbc:Community","","");
		}catch(Exception e){
			System.out.println("getCon");
			System.out.println(e.getMessage());
		}
		return con;
	}
	
	/***************************************************
	*method name:	chStr()<br>
	*method function:	change coding<br>
	*return value:  String<br>
	*		    	return Chainese<br>
	*parameter explain:	str<br>
	*amend:	crazyadept<br>
	*		2004/8/2<br>
	****************************************************/
	public String chStr(String str){
		if(str==null){
			str="";
		}else{
			try{
				str=(new String(str.getBytes("iso-8859-1"),"GB2312")).trim();
			}catch(Exception e){
				System.out.println("chStr");
				System.out.println(e.getMessage());
			}
		}
		return str;
	}

}