CODEWITHSUNDEEP
javaresultset
Chris
Chris

Reputation: 1

Resultset can not be traversed

I want to use while(rs.next()) to traverse the UserInfo table. There are seven records in UserInfo table, but I only got the first record. After I had joined the codes of rs.getRow();, I got the result what I want.

try{
    Statement stmt=conn.createStatement();
    String queryStr="SELECT * FROM UserInfo";
    ResultSet rs=stmt.executeQuery(queryStr);

    while(rs.next())
    {
        String strName="Name is "+rs.getString(3)+";";
        String intAge="Age is "+rs.getInt(5)+";";
        String strCompany="Company is "+rs.getString(4)+".<br>";
        //int rowNum=rs.getRow();
        out.println(strName+intAge+strCompany);
    }

    out.println("Succeed in visiting UserInfo table.");
    }catch(SQLException e){
        out.println("Failed to query.");
    }

I don't want to use rs.getRow();. How should I deal with this problem?

Upvotes: 0

Views: 118

Answers (3)

Jacob
Jacob

Reputation: 14731

Your code does appear to be fine except the String part.If you are using String to hold a record, then you wouldn't be able to display all 7 records.

Thus try using collection object like ArrayList. And of course you should close connections in finally block.

try{
  Statement stmt=conn.createStatement();
  String queryStr="SELECT * FROM UserInfo";
  ResultSet rs=stmt.executeQuery(queryStr);
  List<String> list = new ArrayList<String>();  

  while(rs.next()){

    list.add(rs.getString(3));

  }

 System.out.println("rows "+list.size());
 }catch(SQLException e){
    out.println("exception "+e.getMessage());
 }
 finally{
 rs.close();
 stmt.close();
 conn.close();
 }

This is good example of how you should be retrieving values from database using collection object. http://theopentutorials.com/tutorials/java/jdbc/how-to-retrieve-all-rows-from-mysql-table-using-jdbc/

Upvotes: 1

Alexandru Godri
Alexandru Godri

Reputation: 538

rs.next only tells you if there is a next record.

When you run

ResultSet rs=stmt.executeQuery(queryStr);

This already places the data from the first record into variable rs.

In order to advance to the next record you need to run rs.getRow but only if there is a

next record (check with rs.next).

Upvotes: 0

Srinivasu
Srinivasu

Reputation: 1235

rs.next() Moves the cursor froward one row from its current position. A ResultSet cursor is initially positioned before the first row; the first call to the method next makes the first row the current row;

Upvotes: 0

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