How do I return multiple rows from a JDBC method?

Question

I am currently learning JDBC and can successfully query and retrieve data from a MysQL database. But I would like to run this as a method and return the resultset rows from the method to the calling program.

So far I think I have made an appropriate method but am stuck returning the resultset as an object. Eclipse gives me the following error for the return type:

Object cannot be resolved to a type

Here is the method:

public object getAllPosts(int catID) throws Exception{
    try{
        this.catID = catID;
        sql = "SELECT post_id, post_title, post_content, post_date FROM crm_posts WHERE cat_id = ? LIMIT ?";
        prep = conn.prepareStatement(sql);
        prep.setInt(1, catID);
        prep.setInt(2, 3);
        // execute statement
        rs = prep.getResultSet();

    } catch(Exception e){
        e.printStackTrace();
    }
    return rs;
}

What is the return type I should use or is there a better way of doing this?

EDIT:

As stated in the comments it was a (annoying) typo. Object with a capital O.

Why don't you return a ResultSet? That way calling methods can use it without typecasting. — Frazz
– Frazz, Commented May 31, 2014 at 11:45
Thanks @Braj, feel free to make an answer, and thanks @Frazz Ill use ResultSet. — crmepham
– crmepham, Commented May 31, 2014 at 11:53

Edwin Torres · Accepted Answer · 2014-05-31 11:57:28Z

2

If you're not going to return a ResultSet or Object object, then you should define your return type. You could create your own Post object for each row in the ResultSet, put those objects in a list, and return the list.

answered May 31, 2014 at 11:57

Edwin Torres

2,8641 gold badge15 silver badges15 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

T.G · Accepted Answer · 2014-06-01 17:48:05Z

This is how you do it

public List<MyClassThatRepresentsTableInDatabase> getAllPosts(int catID) throws Exception{
    try{
        this.catID = catID;
        sql = "SELECT post_id, post_title, post_content, post_date FROM crm_posts WHERE cat_id = ? LIMIT ?";
        prep = conn.prepareStatement(sql);
        prep.setInt(1, catID);
        prep.setInt(2, 3);
        // execute statement
        rs = prep.getResultSet();
        List<MyClassThatRepresentsTableInDatabase> ret=new ArrayList<>();
        while(rs.hasNext()){
           MyClassThatRepresentsTableInDatabase item=
                                 new MyClassThatRepresentsTableInDatabase();
           item.setId(rs.getLong("post_id");
           item.setName(rs.getString("post_title");
           item.setContentd("post_content");
           //etc..
           ret.add(item);
        }
        return ret;
    } catch(Exception e){
        e.printStackTrace();
    }
    return new ArrayList();

}

Java Enthusiast · Accepted Answer · 2014-06-01 17:03:42Z

0

Excecute your query in ResultSet and loop it to get your results.

Use the following line of codes :

Statement st=conn.createStatement();
ResultSet rs=st.executeQuery(sql);
while(rs.next()) 
{
     out.println(rs.getString("//Your Column name"));
}

answered Jun 1, 2014 at 17:03

Java Enthusiast

6627 silver badges19 bronze badges

Collectives™ on Stack Overflow

How do I return multiple rows from a JDBC method?

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related