Question

我想使用StringBuffer而不是将字符串与结果连接。我使用此代码转换while循环但我遇到了最后一个if语句的问题。我该怎么做才能转换它？

原始代码：

result = statement.executeQuery(sql);    
String string = "";

    while (result.next()) {
        string += result.getString(("Hello") + ",");
    }

    if (string!= null && !string.isEmpty()) {
        string= string.substring(0, string.length() - 1);
    }

我的尝试：

result = statement.executeQuery(sql);
StringBuffer string = new StringBuffer("");

      while (result.next()) {
        string.append(("Hello") + ",")
      }

      if {
        --- CODE HERE ---
      }

任何帮助？

Answer 1

如果您只想删除最后一个逗号，请尝试以下操作：

StringBuffer buffer = new StringBuffer("");
...
if ( buffer.length() > 0 ) {
    buffer.deleteCharAt( buffer.length() - 1 );
}

Answer 2

    result = statement.executeQuery(sql);    
    StringBuffer buffer = new StringBuffer();

    int length = result.size();

    if(result != null && length > 0)
    {
        while (result.next()) { 
            buffer.append(result.getString(("Hello"));
            if(--length > 0)
                buffer.append(",");
        }
    }

Answer 3

您可以使用if语句执行此操作。

result = statement.executeQuery（sql）;

StringBuffer stringBuffer = new StringBuffer（＆＃34;＆＃34;）;

  while (result.next()) {
    stringBuffer.append(("Hello") + ",")
  }

    if (stringBuffer.length()>0) {
        stringBuffer = new StringBuffer(stringBuffer.substring(0, stringBuffer.length() - 1));
    }

将String参数转换为StringBuffer

3 个答案: