java - Java中ArrayList与SQLite的ArrayList请教

Question

是否有更有效或标准的方法从数据库获取数据？这种方式很舒服，但可能不是最有效的

public ArrayList<ArrayList<String>> getUsers() throws SQLException {
        ArrayList<ArrayList<String>> result = new ArrayList<ArrayList<String>>();
        ArrayList<String> res;
        String query = "SELECT * FROM User";
        try(Connection conn = DriverManager.getConnection(url, propierties)){
            try (Statement stmt = conn.createStatement()) {
                ResultSet rs = stmt.executeQuery(query);
                while (rs.next()) {
                    res = new ArrayList<String>();
                    String id = rs.getString("id_user");
                    String name = rs.getString("name");
                    res.add(id);
                    res.add(name);
                    result.add(res);
                }
            } catch (SQLException e) {
                logger.error(e);
            }
        }
        return result;
    }

Answer 1

您可以创建一个类用户

public class User{
    private String id;
    private String name;

    public User() {
    }

    public User(String id, String name) {
        this.id = id;
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public void setId(Stringid) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

然后代替 ArrayList<ArrayList<String>>您可以使用ArrayList<User>

ArrayList<User> result = new ArrayList<>();
User user;
...
while (rs.next()) {
    user = new User(rs.getString("id_user"), rs.getString("name"));
    result.add(user);
}

最佳实践说明id不要使用 String 类型，而是使用 Integer、Long、..