我想將 z 作為 int 返回，但我無法返回它

Question

我試圖將z作為int返回，但無法這樣做。 我用來實現此目的的代碼如下所示。

public static int pagenumber(String DBmatter, String ClassYear) throws SQLException {

        Statement stmt;
        stmt = con.createStatement();
        ResultSet rs = stmt.executeQuery("select * from page_number where 'matter_name' = '" + DBmatter + ClassYear + "';");
        while (rs.next()) {
            String y = rs.getString(3);
            int z = Integer.parseInt(y);
        }
        return z ;

    }

Answer 1

Statement stmt;
stmt = con.createStatement();
int z = 0;
ResultSet rs = stmt.executeQuery("select * from page_number where 'matter_name' = '" + DBmatter + ClassYear + "';");
while (rs.next()) {
    String y = rs.getString(3);
    z = Integer.parseInt(y);
}
return z ;

您的代碼沒有任何問題，您只需要在while之外聲明z 。

Answer 2

thx 我已經用這個代碼解決了

    String y = "";
    Statement stmt;
    stmt = con.createStatement(); ///SELECT number FROM page_number where matter_name='loghty1B';
    ResultSet rs = stmt.executeQuery("select number from page_number where matter_name='" + DBmatter + ClassYear + "';");

    while (rs.next()) {
        y = rs.getString("number");
        System.out.println("this from Go DB @ While " + y);
        return y;
    }
    return y;

}