通过在 java 中读取 mySQL 表来创建 JSON 文件

Question

我想选择我的数据表并将其内容存储在JSON 文件中。但是我的JSON 文件内容多次只有我表的最后一行。你能帮我找出我错在哪里吗？谢谢...

这是我的java代码的一部分：

 JSONObject obj = new JSONObject();
 JSONArray array = new JSONArray();

 try {
    conn = DriverManager.getConnection(url, utilisateur, motDePasse);
    preparedStatement = conn.prepareStatement("SELECT idUser, emailUser, motPassUser FROM utilisateur;");
    result = preparedStatement.executeQuery("SELECT idUser, emailUser, motPassUser FROM utilisateur;");

    obj = new JSONObject();
    array = new JSONArray();

    while (result.next()) {
        obj.put("id", result.getInt("idUser"));
        obj.put("email", result.getString("emailUser"));
        obj.put("password", result.getString("motPassUser"));
        array.add(obj);
    }

    try {
        FileWriter file = new FileWriter("user.json");
        file.write(((JSONArray) array).toJSONString());
        file.flush();
        file.close();
    } catch (IOException e) {
        e.printStackTrace();
    }
} catch (SQLException e) {

} finally {
    if (result != null) {
        try {
            result.close();
        } catch (SQLException ignore) {
        }
    }
    if (preparedStatement != null) {
        try {
            preparedStatement.close();
        } catch (SQLException ignore) {
        }
    }
    if (conn != null) {
        try {
            conn.close();
        } catch (SQLException ignore) {
        }
    }
}

这是我的 JSON 文件的输出：

[{"id":3,"email":"tindongabou@gmail.com","password":"ludovic1992"},
{"id":3,"email":"tindongabou@gmail.com","password":"ludovic1992"},
{"id":3,"email":"tindongabou@gmail.com","password":"ludovic1992"}]

它只包含我表格的最后一行...

Answer 1

在while循环中创建JSON对象

while (result.next()) {

obj = new JSONObject();

        obj.put("id", result.getInt("idUser"));

        obj.put("email", result.getString("emailUser"));

        obj.put("password", result.getString("motPassUser"));

        array.add(obj);
    }

Answer 2

将此行放在您的 while 循环中 -

obj = new JSONObject();