从 ResultSet 获取结果的问题 [英] Troubles getting results from ResultSet

问题描述

如何让 var 包含我从结果集中获得的所有记录?

How can I have a var which contains all the records I get from a resultset?

到目前为止我有这个代码:

So far I have this code:

    while (rs.next()) {
        for (int i = 1; i <= columnCount; i++) {
            String resultado = "";
            resultado = rs.getString(i);
            columnValue += resultado;
        }
        jTextPane2.setText(jTextPane2.getText() + columnValue + ", ");
    }

我希望当 resultado 从 rs.getString(i) 获取值时，填充 var columnValue 以便我有一个var 应该有我从 rs 得到的所有记录，但它不工作.有什么帮助吗?

I want that when resultado gets the value from the rs.getString(i), fills the var columnValue so that I have a var which SHOULD have all the records I get from the rs, but is not working. Any help?

我得到的结果是:

(id_tlf, cod_area)

(id_tlf, cod_area)

1+58、1+582+104、1+582+1043+60

1+58, 1+582+104, 1+582+1043+60

如您所见，前 2 个结果在每一行中重复

so as you see, the first 2 results repeat in every row

推荐答案

请更喜欢 StringBuilder 来创建大量 String 临时值(它们会污染内部缓存事物).接下来，您不需要将每一列存储在另一个局部变量中.基本上，我会做类似的事情

Please prefer a StringBuilder to creating lots of String temporary values (they pollute the intern cache for one thing). Next, you don't need to store each column in another local variable. Basically, I would do something like

StringBuilder sb = new StringBuilder();
while (rs.next()) {
    for (int i = 1; i <= columnCount; i++) {
        if (i != 1) {
            sb.append(", ");
        }
        sb.append(rs.getString(i));
    }
    sb.append(System.lineSeparator());
}
jTextPane2.setText(sb.toString());

注意上面清除了jTextPane2，如果你打算追加，那么你可以将第一行更改为类似

Note the above clears jTextPane2, if you intend to append then you could change the first line to to something like

StringBuilder sb = new StringBuilder(jTextPane2.getText());
sb.append(System.lineSeparator()); // <-- start the next line... and then iterate rs

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