java - 如何将sql数组值从java Controller 传递到scala模板

Question

我是刚玩框架的新手。我想将 java Controller 中的数组变量传递给 scala 模板。

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)
    );

和 scala 模板

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

我收到错误

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

我需要将 rset 值传递给 scala template 。但我不知道该怎么办请帮助我

Answer 1

您需要在 try block 之外声明 rset:

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)
    );

这个解决方案并不是很漂亮，因为如果发生 SQL 异常，rset 将为 null，并且您将在模板中遇到麻烦 (NullPinterException)。您可能需要考虑将 return 语句移至 try block 的末尾，并将另一个语句添加到 catch block 中以进行错误处理。