从文件中读取数据并将其添加到数据库而不添加相同的值

Question

所以我有这个程序读取文本文件并将其内容添加到我的数据库。我这里没问题。但是当新内容添加到文件并且程序再次运行时，所有值都从头开始存储在数据库中，但我只是希望在我第二次运行程序时将新内容添加到顶部。我怎么能这样做，这是我的代码。在此先感谢!!

        public static void main(String[] args) throws IOException, SQLException {

    PreparedStatement preparedstatement = null;


    try{
        String read=null;
        in = new BufferedReader(new FileReader("patientlist.txt")); 
        while ((read = in.readLine()) != null) {
            String[] splited = read.split("\\s+");
            name=splited[0];
            age=splited[1];
            height=splited[2];
            weight=splited[3];      
            addpatient(connection, preparedstatement, name, age, height, weight);
        }

    }
    catch (IOException e) {System.out.println("There was a problem: " + e);}
        if (connection != null)
        try{connection.close();} catch(SQLException ignore){} 
    }


    public static void addpatient(Connection connection, PreparedStatement preparedstatement, String name, String age, String height, String weight) throws SQLException{
    preparedstatement=connection.prepareStatement("insert into allpatients(name, age, height, weight) values(?,?,?,?)");
    preparedstatement.setString(1, name);
    preparedstatement.setString(2, age);
    preparedstatement.setString(3, height);
    preparedstatement.setString(4, weight);
    preparedstatement.executeUpdate();


    }

Answer 1

if (!isPatent(connection, preparedstatement, name)) 
    addpatient(connection, preparedstatement, name, age, height, weight);



    public static boolean isPatient(Connection connection,
            PreparedStatement preparedstatement, String name)
            throws SQLException {
        boolean exists = false;
        preparedstatement = connection
                .prepareStatement("select * from allpatients where name = ?");

        preparedstatement.setString(1, name);
        ResultSet rs = preparedstatement.executeQuery();
        if (rs.next()) {
            exists = true;
        }
        rs.close();
        return exists;
    }