删除StringBuilder的最后一个字符？ [英] Remove last character of a StringBuilder?

问题描述

当你必须遍历一个集合并用分隔符分隔每个数据的字符串时，你最终总会得到一个额外的分隔符，例如

When you have to loop through a collection and make a string of each data separated by a delimiter, you always end up with an extra delimiter at the end, e.g.

for(String serverId : serverIds) {
 sb.append(serverId);
 sb.append(",");
}

提供类似的内容： serverId_1，serverId_2，serverId_3，

我想删除StringBuilder中的最后一个字符（不进行转换，因为在循环之后我仍然需要它。）

I would like to delete the last character in the StringBuilder (without converting it because I still need it after this loop).

推荐答案

其他人已指出 deleteCharAt 方法，但这是另一种替代方法：

Others have pointed out the deleteCharAt method, but here's another alternative approach:

String prefix = "";
for (String serverId : serverIds) {
  sb.append(prefix);
  prefix = ",";
  sb.append(serverId);
}

或者，使用 Joiner class来自番石榴：）

从Java开始8， StringJoiner 是标准JRE的一部分。

As of Java 8, StringJoiner is part of the standard JRE.

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