如何将SQL数组值从Java控制器传递到Scala模板

Question

I am new to play framework. I want to pass array variables in java controller to scala template.

try {
            String userName = "data";

            String password = "data";

            String url = "jdbc:mysql://localhost/playdb";

            // Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            Connection con = DriverManager.getConnection(url, userName, password);
            Statement stmt = con.createStatement();
            System.out.println("Connected database successfully...");
            String strSelect = "select * from computer";

            //statement.setString(1, name);
            ResultSet rset = stmt.executeQuery(strSelect);

            while(rset.next()) {   // Move the cursor to the next row
                String name = rset.getString("name");

                int    id   = rset.getInt("id");
                System.out.println( name + ", " + id);
                // ++rowCount;
            }


        }
        catch(SQLException e) {
            e.printStackTrace();
            System.out.println("cant Connected database successfully...");
        }
        Form<Computer> computerForm = form(Computer.class);
      return ok(
        createForm.render(computerForm,rset)
    );

and scala templete

    @(computerForm: Form[Computer],createFormRset: String)

i got the error

cannot find symbol [symbol: variable rset] [location: class controllers.Application]

I need to pass rset value to scala template . But I don't know how please help me

Answer 1

You need to declare rset outside of your try-block:

ResultSet rset = null;
try {
            String userName = "data";

            String password = "data";

            String url = "jdbc:mysql://localhost/playdb";

            // Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
            Connection con = DriverManager.getConnection(url, userName, password);
            Statement stmt = con.createStatement();
            System.out.println("Connected database successfully...");
            String strSelect = "select * from computer";

            //statement.setString(1, name);
            rset = stmt.executeQuery(strSelect);

            while(rset.next()) {   // Move the cursor to the next row
                String name = rset.getString("name");

                int    id   = rset.getInt("id");
                System.out.println( name + ", " + id);
                // ++rowCount;
            }


        }
        catch(SQLException e) {
            e.printStackTrace();
            System.out.println("cant Connected database successfully...");
        }
        Form<Computer> computerForm = form(Computer.class);
      return ok(
        createForm.render(computerForm,rset)
    );

This solution is not really pretty, because if an SQL-Exception occurs, rset will be null and you will run into troubles in your template ( NullPinterException ). You might want to consider to move your return statement at the end of the try-block and add another one into the catch block for error handling.

Answer 2

Basically you can pass any java object to the template. Play framework has type-checking on views so you would have to declare the rset. If you look at the computer-database sample that comes with Play, you'll see it passes a Page object and three strings:

@(currentPage: com.avaje.ebean.Page[Computer], currentSortBy: String, currentOrder: String, currentFilter: String)

However, you may find it easier to copy the values from rset into your computerForm object, or another POJO, and pass that to the template.