Java 如何将值写入文本文件并将值存储为inputStream

我需要您的帮助，将值写入文本文件，并将写入的数据转换为inputStream，以便将其附加到按钮。对于硬编码的字符串，我可以这样做，请参考以下方法：

private StreamedContent txtFile;
        public void createTxt(ActionEvent actionEvent) {

    try {
        String string = "This is a String.\nWe are going to convert it to InputStream.\n";
        InputStream inputStream = new ByteArrayInputStream(string.getBytes(Charset.forName("UTF-8")));
        txtFile = new DefaultStreamedContent(inputStream, "application/txt", "sample.txt");
    } catch (Exception e) {
        e.printStackTrace();
    }

}

现在，我需要从数据库中读取数据，因此我已完成以下操作：

private StreamedContent txtFile;
        public void createTxt(ActionEvent actionEvent) {

    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection(DB_URL, USER, PASS);
        stmt = conn.createStatement();

        String sql = "SELECT id, name, amount FROM Employee";
        ResultSet rs = stmt.executeQuery(sql);

            while(rs.next()){
                int id  = rs.getInt("id");
                int age = rs.getString("name");
                String first = rs.getInt("amount");
               } 
            rs.close();
        InputStream inputStream = new ByteArrayInputStream(string.getBytes(Charset.forName("UTF-8")));
        txtFile = new DefaultStreamedContent(inputStream, "application/txt", "sample.txt");
    } catch (Exception e) {
        e.printStackTrace();
    }

}

因此，现在我需要您的帮助，在读取每条记录后，从数据库中写入由“|”分隔的获取值，并在其中添加一行新行，然后将完整值转换为

inputStream

，答案如下：

private StreamedContent txtFile;
        public void createTxt(ActionEvent actionEvent) {

try {
    Class.forName("com.mysql.jdbc.Driver");
    StringBuilder builder = new StringBuilder();
    conn = DriverManager.getConnection(DB_URL, USER, PASS);
    stmt = conn.createStatement();

    String sql = "SELECT id, name, amount FROM Employee";
    ResultSet rs = stmt.executeQuery(sql);

        while(rs.next()){
            int id  = rs.getInt("id");
            int age = rs.getString("name");
            String first = rs.getInt("amount");
            builder.append(id+"|"+age+"|"+first+"\n");
           } 
        rs.close();
        String result = builder.toString();
    InputStream inputStream = new ByteArrayInputStream(result.getBytes(Charset.forName("UTF-8")));
    txtFile = new DefaultStreamedContent(inputStream, "application/txt", "sample.txt");
} catch (Exception e) {
    e.printStackTrace();
}

}

---

您到底有什么问题？@KPrince36我需要将内容字符串写入文本文件，但为了存储，我需要将其转换为InputStream。请看教程。我现在需要将JDBC教程链接到您吗？例如，将从数据库读取的数据放入

StringBuilder

中。请阅读教程，我不相信你自己已经写了一半的代码。