I'm using Java Servlet to create customized blogs. I want to get the number of rows in a table of a database. After I get it, I use for() loop to get the data of each message and then join all one-by-one in the loop. Then, pass it to the blogs.jsp page. Here is the code.
try {
ses=request.getSession(true);
String ses_val=(String)ses.getAttribute("username");
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
con=DriverManager.getConnection("jdbc:odbc:harshan_web");
if (ses_val==null)
{
response.sendRedirect("error.html");
}
else
{
if (con!=null)
{
SimpleDateFormat blog_time1=new SimpleDateFormat("HH:mm:ss");
Date blog_time2=new Date();
StringBuilder blog_time = new StringBuilder( blog_time1.format( blog_time2 ) );
username=ses_val;
blog_message=request.getParameter("memo1");
if ((username!=null)&&(blog_message!=null))
{
st=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
st2=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
st2.executeUpdate("insert into blog(username,blog_message,blog_time) values('"+username+"','"+blog_message+"','"+blog_time+"')");
ResultSet rs=st.executeQuery("select count(*) as tot_count from blog");
if (rs.next()){
//rs.last();
//int count=rs.getRow();
int count=rs.getInt("tot_count");
String blogs="";
for (int i=1; i<=count; i++)
{
ResultSet rs2=st.executeQuery("select * from blog where ID="+i+"");
String user1=rs2.getString("username");
String blog_m=rs2.getString("blog_message");
String blog_t=rs2.getString("blog_time");
blogs="<div><table border='0' bgcolor='#6ca6cd' cellpadding='20' cellspacing='20'><tr><td>"+user1+"<br><br>"+blog_t+"</td><td>"+blog_m+"</td></tr></table></div>"+blogs;
}
response.sendRedirect("blogs.jsp?blogs="+blogs+"");
}
else
{
String no_blog="There are 0 blogs in this page!!!";
response.sendRedirect("blogs.jsp?invalid_login="+no_blog+"");
}
}
else
{
st=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
st2=con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
ResultSet rs=st.executeQuery("select count(*) as tot_count from blog");
if (rs.next()){
//rs.last();
//int count=rs.getRow();
int count=rs.getInt("tot_count");
String blogs="";
for (int i=1; i<=count; i++)
{
ResultSet rs2=st.executeQuery("select * from blog where ID="+i+"");
String user1=rs2.getString("username");
String blog_m=rs2.getString("blog_message");
String blog_t=rs2.getString("blog_time");
blogs="<div><table border='0' bgcolor='#6ca6cd' cellpadding='20' cellspacing='20'><tr><td>"+user1+"<br><br>"+blog_t+"</td><td>"+blog_m+"</td></tr></table></div>"+blogs;
}
response.sendRedirect("blogs.jsp?blogs="+blogs+"");
}
else
{
String no_blog="There are 0 blogs in this page!!!";
response.sendRedirect("blogs.jsp?invalid_login="+no_blog+"");
}
}
}
else
{
response.sendRedirect("error.html");
}
} catch (Exception e) {System.out.print(e);} finally {out.close();}
I thought everything was right. But when I ran it, I get only the following exception.
java.sql.SQLException: invalid cursor state;
I can't understand what the ResultSet cursor could be. The new values are entered in the database. But, the problem is when trying to display the blog values in a .jsp file by requesting the value of blogs.
What can I do to make it right. Can we make self-customized blog code OR should we compulsarily use a blog engine?
int count=rs.getRow();is not doing what you think it is doing, at all. Read the javadoc. – Sotirios Delimanolis Oct 26 '13 at 16:36ResultSet– Jarrod Roberson Oct 26 '13 at 16:37catch (Exception e) {System.out.print(e);}because it hides the line numbers where the exception occurs, which makes life unnecessarily difficult for you when trying to debug. If you must catch an exception, usee.printStackTrace()instead. – Robin Green Oct 26 '13 at 20:35