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How to read a file using JSP?

Anyone can help me on this? I will be grateful if there is a kind soul offering his/her help.

I need to read information from a file and put into my SELECT statement in my JSP file. Something like the codes below...

<SELECT NAME="test" ><%= function getfile()%></SELECT>

So function getfile() will generate all my OPTIONS.

Thank you.

sudhakar_koundinya

Do u want read the text from Server file or Client File?

sudhakar_koundinya

package logging;
import java.io.*;

public class UsersReader
{
public FileReader filer=null;
StringBuffer data=null;

public String read(String file)throws Exception
{
filer=new FileReader (file);
data=new StringBuffer();
while(true)
{
int c=filer.read();
if(c==-1) break;
data.append(""+(char)c);
}
return data.toString();
}
}

here is the file to read text

sudhakar_koundinya

<%@ page import=logging.*%>
<%
UsersReader ur= new UsersReader();
String s=ur.read("/weblogic/myserver/public_html/MyText.txt");
out.println(s);

%>

here is jsp code

sudhakar_koundinya

<%@ page import=logging.*%>
<%
UsersReader ur= new UsersReader();
String s=ur.read("/weblogic/myserver/public_html/MyText.txt");
out.println(s);

%>

here is jsp code

ASKER

sudhakar,

Thanks for your reply, what if I need to spilt the line that i read earlier? Is there any function to do so?
I have comma delimited records in my text file for ex:
AP,SWE,SWEDEN

Cheers
Jason

sudhakar_koundinya

Use StringTokenizer class that is available with java.util package

Here is sample code

StringTokenizer st=new StringTokenizer("AP,SWE,SWEDEN",",");

while(st.hasMoreTokens())
{
%>
<SELECT NAME="test" ><%= st.nextToken()%></SELECT>
<%

}

Regards
Sudhakar

ASKER

sudhakar,

How do I call a function?? For example:-

-----------------------------------------------------------
<%@ page language="java" %>
<%@ page import="java.util.*, java.io.*, java.net.*" %>
<%! public String getCountries() {
String addText="";
String cntry_cd="";
String cntry_nm="";

Class.forName("com.sun.jdbc.driver");
String url= "jdbc:sqli://123.256.456:1234/test";

Connection conn = DriverManager.getConnection(url,"test","test");

DatabaseMetaData meta = conn.getMetaData();
Statement stmt = conn.createStatement();
String sql = "select * from country";
ResultSet rslt = stmt.executeQuery(sql);
while ( rslt.next() )
{
cntry_cd = rslt.getString("ctry_cd");
cntry_nm = rslt.getString("ctry_nm");

addText = addText + "<OPTION VALUE=\"" + cntry_cd + "\">" + cntry_nm + "</OPTION>\n";
}

stmt.close();
conn.close();
return addText;
}
%>
<HTML>
<HEAD>
<TITLE>Commodity Page</TITLE>
</HEAD> <BODY> <center> <IMG SRC=/images/wsisupport/webshipping.gif height=100>
<HR> </center> <FORM NAME="login" ACTION="test.jsp" METHOD="post">
<TABLE BORDER=0 CELLSPACING=4 CELLPADDING=3 WIDTH="100%">
<TR>
<TH>Commodity Search</TH>
</TR>

<TR> <TD>Select Country</TD>
<TD><SELECT NAME="country"><%= getCountries() %></SELECT></TD>
</TR></TABLE>
</BODY>
</HTML>

-----------------------------------------------------------

I would be grateful if you can point out my errors. By the way how I call a function in JSP, I am getting uncomfortable using JSP, how do I brush up my Java? Any comments?

Thanks for your guidence.

Cheers
Jason

sudhakar_koundinya

what is the exeption u r getting?

sudhakar_koundinya

what is the exception u r getting?

sudhakar_koundinya

<%@ page language="java" %>
<%@ page import="java.util.*, java.io.*, java.net.*,java.sql" %>
<%! public String getCountries() throws Exception{
String addText="";
String cntry_cd="";
String cntry_nm="";

Class.forName("com.sun.jdbc.driver");
String url= "jdbc:sqli://123.256.456:1234/test";

Connection conn = DriverManager.getConnection(url,"test","test");

DatabaseMetaData meta = conn.getMetaData();
Statement stmt = conn.createStatement();
String sql = "select * from country";
ResultSet rslt = stmt.executeQuery(sql);
while ( rslt.next() )
{
cntry_cd = rslt.getString("ctry_cd");
cntry_nm = rslt.getString("ctry_nm");

addText = addText + "<OPTION VALUE=\"" + cntry_cd + "\">" + cntry_nm + "</OPTION>\n";
}

stmt.close();
conn.close();
return addText;
}
%>
<HTML>
<%

try
{
%>
<HEAD>
<TITLE>Commodity Page</TITLE>
</HEAD> <BODY>
<center> <IMG SRC=/images/wsisupport/webshipping.gif
height=100>
<HR> </center>
<FORM NAME="login" ACTION="test.jsp" METHOD="post">
<TABLE BORDER=0 CELLSPACING=4 CELLPADDING=3 WIDTH="100%">
<TR>
<TH>Commodity Search</TH>
</TR>

<TR> <TD>Select Country</TD>
<TD><SELECT NAME="country"><%= getCountries() %></SELECT></TD>
</TR></TABLE>
</BODY>
<%

}
catch(Exception e)
{
}
%>

Check this code

sudhakar_koundinya

u missed to import java.sql classes
u missed to include try and catch statements

sudhakar_koundinya

String sql = "select * from country";
cntry_cd = rslt.getString("ctry_cd");
cntry_nm = rslt.getString("ctry_nm");

if u check above three lines

as u need only two columns
modify ur sql statement as

"select cntry_cd,cntry_nm from country";
if(the country have more than 2 columns only)

so that u can reduce the burden to database

ASKER

Sudhakar,

I have another question. How can I separate the connection to the database using another function. I have written some codes but I need to know why it fails. The error message was refering to the "return conn;" It says that this may not have been initialised.

Please help.

Below is the code:

-----------------------------------------------------------
<%@ page language="java" %>
<%@ page import="java.util.*, java.io.*, java.net.*, java.sql.*" %>
<%! public static java.sql.Connection Dbopen()
{
Connection conn;
try{
Class.forName("com.informix.jdbc.IfxDriver");
String url = "jdbc:informix-sqli://199.40.141.122:2222/webship:I
NFORMIXSERVER=wsi_srv;ONCONFIG=onconfig.wsi;DBDATE=DMY2;DBCENTURY=C";
conn = DriverManager.getConnection(url,"webship","wsp123");
} catch (ClassNotFoundException cnfe){ System.err.println("Error loading driver");
} catch (SQLException sqle){ System.err.println(sqle);}
return conn; <----------------ERROR HERE!
}
public String getCountries()
{
String addText="";
String cntry_cd="";
String cntry_nm="";
Connection conn1 = Dbopen();
Statement stmt = conn1.createStatement();
try{
String sql = "select cntry_cd,cntry_nm from country";
ResultSet rslt = stmt.executeQuery(sql);
while ( rslt.next() )
{
cntry_cd = rslt.getString("ctry_cd");
cntry_nm = rslt.getString("ctry_nm");

addText = addText + "<OPTION VALUE=\"" + cntry_cd + "\">" + cntry_nm + "</OPTION>\n";
}catch (SQLException sqle){
System.err.println(sqle);
}
stmt.close();
conn1.close();
return addText;
}
try
{
%>
<HEAD>
<TITLE>Commodity Page</TITLE>
</HEAD> <BODY>

<center> <IMG SRC=/images/wsisupport/webshipping.gif

height=100>
<HR> </center>

<FORM NAME="login" ACTION="test.jsp" METHOD="post">
<TABLE BORDER=0 CELLSPACING=4 CELLPADDING=3 WIDTH="100%">
<TR>
<TH>Commodity Search</TH>
</TR>

<TR> <TD>Select Country</TD>
<TD><SELECT NAME="country"><%= getCountries() %></SELECT></TD>
</TR></TABLE>
</BODY>
<%

}
catch(Exception e)
{
}
%>

-----------------------------------------------------------
Please help.

Thank you

Cheer
Jason

ASKER CERTIFIED SOLUTION

sudhakar_koundinya

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ASKER

How do i do paging in jsp?? I wanted to display 10 records per page. Do u mind to provide me the skeleton structure so that I can study on it? Your help is much appreciated.

Thank you

Cheers
Jason

sudhakar_koundinya

Okay u can do one thing

<%
int page=1;

int n=1;
while(rs.next())
{
n++;
if(n%10==0)
{
%>
<a href =doposting(<%=page%>)<%=page%></a>
<%
page++;
}
}
%>

This is some what a rough skeleton

If u understand this idea u can do further

Cheers

Sudhakar

ASKER

Sudhakar,

I understand the skeleton structure that you sent, but how do i control the the records to be shown? If the first page ends with 10 records, how do I control such that the second page that I clicked will continue from the eleventh records onward for the next ten records?
I have come across ASP and the have a Page Size and Page count to actually do this trick. Does java have this technique?

Thanks

Cheers
JAson

sudhakar_koundinya

Hi

First tell me what is the database u r using?

If u r using oracle

modify ur sql statement as

String page="0";
if(request.getParameter("page")==null)
{
page="0";
}

String sql="select cntry_cd,cntry_nm from country where rownum<"+Integer.parseInt(page)+
minus select cntry_cd,cntry_nm from country where rownum<"+Integer.parseInt(page)-1;

regards

Sudhakar

ASKER

Sudha,

I am using Informix. Will there be any problem?

Cheers
Jason

sudhakar_koundinya

Hi Jason ,

Yes this query string will work in oracle only.Because rownum is special keyword provided in oracle.
If u find the equivalent let me know that.

String sql="select cntry_cd,cntry_nm from country where rownum<"+Integer.parseInt(page)+
minus select cntry_cd,cntry_nm from country where rownum<"+Integer.parseInt(page)-1;

By the way try this idea. but this is slow.

String page="0";
if(request.getParameter("page")==null)
{
page="1";
}

int start =Integer.parseInt(page)-1*10;
int end=Integer.parseInt(page)*10;

int n=0;
while rs.next())
{
if(n>=start && n<=end)
{
//print the info u want here
}
if(n>end)
break;
n+=1;
}

Regards sudhakar

By this is my personal interest.Where r u from?

because only Indians call sudhakar as sudha (In friends circle and family only)

ASKER

Sudha,

I am a Malaysian chinese by the way, in that case can you suggest other solution with reagrds to my qs?

Cheers
Jason

sudhakar_koundinya

Hi Jason

I think we have to close this session now.

Don't u think this session is boring now.If 4-5 friends are in discussion we can exchange more ideas.Just close this session and start the new session.When u start new thread just mail me to sudhakar_koundinya@yahoo.com . I will help u by participating in the new thread.

Cheers

Koundinya

ASKER

Sure do mate.....

By the way how do i close this session?????

Cheers

sudhakar_koundinya

u will find accept comment option ur side.just click on that and site ask u to grade this session.just click on one of the grades accept it.

Cheers
Koundinya.

ASKER

It's all yours mate!