小试从数据库读取数据到文件

读数据库写入文本文件：

程序代码

public static void readDataToTxt() throws Exception
{
     Long d=new Date().getTime();
     PrintWriter pw= new PrintWriter(new BufferedWriter(new FileWriter("c://a.txt",true)));
     Idao dao=Dao.getInstance();
     List list=dao.search("from User n");
     Iterator it=list.iterator();
     String result;
     String newline = "/r/n";
        try{
        while(it.hasNext())
        {
                                   User user=(User)it.next();
                       result=user.getId()+","+user.getUserName()+","+user.getUserPwd()+","+user.getUserEmail();
                          pw.write(result);
                          pw.write(newline);

                                }
        Long d2=new Date().getTime();
        pw.write(String.valueOf(d2-d));
           pw.close();
        }catch(Exception e){
            e.printStackTrace();
        }finally{
        }

}    

读数据库写入xls文件：

程序代码

  public static void readDataToExcel() throws Exception
  {
     Long d=new Date().getTime();
                 WritableWorkbook book  =  Workbook.createWorkbook( new  File( "WebRoot/user/aa.xls" ));   
                 WritableSheet sheet  =  book.createSheet( "test" , 0 );   
     Idao dao=Dao.getInstance();
     List list=dao.search("from User n");
     int num=dao.searchCount("select count(*) from User n");
     Iterator it=list.iterator();
     int t=0;
     Label label=null;
     Label label2=null;
     Label label3=null;
     Label label4=null;
    try{
    while(it.hasNext())
        {
                                User user=(User)it.next();
                   if(t<num)
                   {
                       label  = new Label( 0 ,t ,String.valueOf(user.getId()));
                       label2 = new Label( 1 ,t ,user.getUserName());
                       label3 = new Label( 2 ,t ,user.getUserPwd());
                       label4 = new Label( 3 ,t ,user.getUserEmail());
                       sheet.addCell(label);  
                       sheet.addCell(label2); 
                       sheet.addCell(label3); 
                       sheet.addCell(label4);
                   }    
                   t=t+1;
                                }    
         Long d2=new Date().getTime();
         System.out.println(d2-d);
         Label label5=new Label( 0 ,t+1 ,String.valueOf(d2-d));;
                                 book.write();   
                                 book.close();   
        }catch(Exception e){
            e.printStackTrace();
        }finally{

        }
  }

用jdbc访问读取数据到excel文件：

程序代码

  public static void readDataToExcel3() throws Exception
  {
     Long d=new Date().getTime();
     WritableWorkbook book  =  Workbook.createWorkbook( new  File( "c://3.xls" ));   
      //生成名为“test”的工作表
     WritableSheet sheet  =  book.createSheet( "test" , 0 );   
     int t=0;
     Label label=null;
     Label label2=null;
     Label label3=null;
     Label label4=null;
     String sql="select * from user";
     int rn=0;
     Statement stms=null;
     ResultSet rs=null;
        try{
        stms=Db.getStm();
        rs=stms.executeQuery(sql);
        while(rs.next())
            {
                       label  = new Label( 0 ,rn ,String.valueOf(rs.getInt(1)));
                       label2 = new Label( 1 ,rn ,rs.getString(2));
                       label3 = new Label( 2 ,rn ,rs.getString(3));
                       label4 = new Label( 3 ,rn ,rs.getString(4));
                       sheet.addCell(label);  
                       sheet.addCell(label2); 
                       sheet.addCell(label3); 
                       sheet.addCell(label4);
                       rn=rn+1;
            }    
         Long d2=new Date().getTime();

         Label label5=new Label( 0 ,rn+1 ,String.valueOf(d2-d));
         sheet.addCell(label5);             
         //  写入数据并关闭文件  
         book.write();   
         book.close();   
        }catch(Exception e){
            e.printStackTrace();
        }finally{

        }

  }