在Java中，我试图从ResultSet中获取空值

Question

private boolean checkingDataBase(String email) {
    String query = String.format("SELECT email FROM users where email = '%s'", email);
    try (Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery(query)) {
        String s = "";
        if (rs.getString("email").isEmpty()){
            System.out.println("true");
            return true;    
        }
        else {
            System.out.println("faaalse");
            return false;
        }

    } catch (SQLException e) {
        e.printStackTrace();
    } return false;
}

我认为，我做错了所有事情。任何人都可以展示一种如何使其正确的方法]

Answer 1

private boolean checkingDataBase(String email) {
    String query = String.format("SELECT * FROM users where email = '%s'", email);
    try (Statement stmt = conn.createStatement();
           ResultSet rs = stmt.executeQuery(query)) {
         return rs.next() && rs.getString("email").isEmpty();
    } catch (SQLException e) {
        e.printStackTrace();
    }

    return false;
}

Answer 2

尝试一下

String query = String.format("SELECT * FROM users where email = '%s'", email);
try (Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery(query)) {
        String s = "";
        boolean flag=false;
        while(rs.next()){
         if (rs.getString("email").isEmpty()){
            System.out.println("true");
            flag=true;    
        }}
        return flag;
    }