db.java

java swing 和sql server 数据库做的 图书管理系统

package bookmanager.bean;
import java.sql.*;
//import java.sql.DriverManager;
//import oracle.jdbc.OracleDriver;
//import oracle.jdbc.pool.OracleDataSource;
//import javax.sql.DataSource;
import javax.sql.*;
import java.math.*;
import java.io.*;
import javax.naming.*;


import java.lang.*;


public class DB {

private Connection con;
private Statement stmt;
private ResultSet rs;
private String db_driver,db_sid,db_user,db_pwd;


public DB() {

  db_driver="net.sourceforge.jtds.jdbc.Driver";
  db_sid="jdbc:jtds:sqlserver://localhost:1433;DatabaseName=BookManager"; 
 
  db_user="sa";			
  db_pwd="3591021";        				

try{
 Class.forName(db_driver);

 con=DriverManager.getConnection(db_sid,db_user,db_pwd);
 stmt=con.createStatement();

}catch (Exception ex)
{
    ex.printStackTrace();

    con = null;
    stmt = null;
    rs = null;
    db_driver=null;
}
}

public String  dbInsert(String sql)
{
 if(stmt==null) return "stmt==null";
  boolean  f;
  try{
    f=stmt.execute(sql);
  }
   catch (Exception ex){
    System.out.println(sql);
   ex.printStackTrace();
   f=false;
 }
  return String.valueOf(f);
}

public ResultSet executeQuery(String sql) {

	rs = null;
	try {
		rs = stmt.executeQuery(sql);
	}
	catch(Exception  ex) {
		
	 ex.printStackTrace();
	 return null;
	}
	return rs;
}



public int executeUpdate(String sql) {
int reti;
 try {
		reti=stmt.executeUpdate(sql);
	}
	catch(Exception  ex) {
	ex.printStackTrace();
	System.err.println("db.lookupName: " + ex.getMessage());
	reti=-1;
	}
    return reti;
}

public void closeCon(){
	if(rs != null){
		try{
			rs.close();
		}catch(SQLException e){e.printStackTrace();}
		rs = null;
	}
	if(stmt != null){
		try{
			stmt.close();
		}catch(SQLException e){e.printStackTrace();}
		stmt = null;
	}
	if(con != null){
		try{
			con.close();
		}catch(SQLException e){e.printStackTrace();}
		con = null;
	}
}

//��4��ʾ�������壻
public String getStr(String str) {
	try {
		String temp_p=str;
		byte[] temp_t=temp_p.getBytes("ISO8859-1");
		String temp=new String(temp_t);
		return temp;
	}
	catch(Exception e) {
		e.printStackTrace();
	}
	return "null";
}

}