Java 和 Mysql 使用 Arraylist 更新所有记录

Question

我试图运行程序所有更新的记录以显示在该程序上，但 mysql 没有变化。

    try 
    {
        User user = new User(null, null);
        user.setId(5);
        user.setName("spider");
        user.setPlatform("Mac"); 
        updateRecordToTable(user);

    ArrayList<User> userlists=new ArrayList<User>();

        userlists.add(new User("alish","Windows"));
        userlists.add(new User("galish","Ubundu"));
        userlists.add(new User("balish","Boss"));
    } 
    catch (SQLException e) 
    {

        System.out.println(e.getMessage());

    }

}

private static int updateRecordToTable(User user) throws SQLException 
{

    Connection dbConnection = null;
    PreparedStatement preparedStatement = null;

    String updateTableSQL = "UPDATE NEWDB SET NAME =? , PLATFORM = ?  WHERE ID =? ";

    try 
    {
        dbConnection = getDBConnection();
        preparedStatement = dbConnection.prepareStatement(updateTableSQL);

        System.out.println("Record is updated all to NEWDB table!");

    } 

尝试修复这个程序。

Answer 1

你必须使用参数。

private static int updateRecordToTable(ArrayList<User> users) throws SQLException 
{
  int i = 0;
  Connection dbConnection = null;
  PreparedStatement preparedStatement = null;

  String updateTableSQL = "UPDATE NEWDB SET NAME =? , PLATFORM = ?  WHERE ID =? ";

try 
{
    dbConnection = getDBConnection();
    for (User user : users){
       preparedStatement = dbConnection.prepareStatement(updateTableSQL);
       preparedStatement .setString(1, user.getName());
       preparedStatement .setString(2, user.getPlatform());
       preparedStatement .setInt(3, user.getId());
       preparedStatement .executeUpdate();
       i++;
    }
    dbConnection.commit();

    System.out.println(i + " Records updated!");

}