如何使用空行拆分段落？

Question

我试着用两个空行来拆分段落。我尝试使用String.split()、StringTokenizer和StringUtils类，但都不起作用。

下面是我的代码：

   DeviceNames (interfacename) # show commands
   Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
   O - OSPF, IA - OSPF inter area
   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
   E1 - OSPF external type 1, E2 - OSPF external type 2
   i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter    area
   * - candidate default

  S*      0.0.0.0/0 [1/0] via 172.16.0.1, internal
  S       10.100.8.0/21 [10/0] is directly connected, vlink10
  C       0.0.2.0/24 is directly connected, internal
  C       0.0.2.0/24 is directly connected, wan1


  DeviceNames (interfacename) # show commands
  Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
   O - OSPF, IA - OSPF inter area
   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
   E1 - OSPF external type 1, E2 - OSPF external type 2
   i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
   * - candidate default

  S*      0.0.0.0/0 [10/0] is directly connected, vlink21
              [10/0] is directly connected, vlink30
  C       0.0.2.0/24 is directly connected, vlink30
  C       0.0.2.0/32 is directly connected, vlink30
  C       0.0.2.0/24 is directly connected, vlink21
  C       0.0.2.0/32 is directly connected, vlink21


  DeviceNames (interfacename) # show commands
  Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
   O - OSPF, IA - OSPF inter area
   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
   E1 - OSPF external type 1, E2 - OSPF external type 2
   i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
   * - candidate default

   S*      0.0.0.0/0 [10/0] is directly connected, vlink11
              [10/0] is directly connected, vlink31
   C       0.0.1.0/24 is directly connected, vlink31
   C       0.0.1.0.1.1/32 is directly connected, vlink31

我想拆分上面的代码，如下所示：

   DeviceNames (interfacename) # show commands
   Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
   O - OSPF, IA - OSPF inter area
   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
   E1 - OSPF external type 1, E2 - OSPF external type 2
   i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter    area
   * - candidate default

  S*      0.0.0.0/0 [1/0] via 172.16.0.1, internal
  S       10.100.8.0/21 [10/0] is directly connected, vlink10
  C       0.0.2.0/24 is directly connected, internal
  C       0.0.2.0/24 is directly connected, wan1

下一个：

   DeviceNames (interfacename) # show commands
  Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
   O - OSPF, IA - OSPF inter area
   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
   E1 - OSPF external type 1, E2 - OSPF external type 2
   i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
   * - candidate default

  S*      0.0.0.0/0 [10/0] is directly connected, vlink21
              [10/0] is directly connected, vlink30
  C       0.0.2.0/24 is directly connected, vlink30
  C       0.0.2.0/32 is directly connected, vlink30
  C       0.0.2.0/24 is directly connected, vlink21
  C       0.0.2.0/32 is directly connected, vlink21

下一个：

   DeviceNames (interfacename) # show commands
   Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
   O - OSPF, IA - OSPF inter area
   N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
   E1 - OSPF external type 1, E2 - OSPF external type 2
   i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
   * - candidate default

   S*      0.0.0.0/0 [10/0] is directly connected, vlink11
              [10/0] is directly connected, vlink31
   C       0.0.1.0/24 is directly connected, vlink31
   C       0.0.1.0.1.1/32 is directly connected, vlink31

Answer 1

一种解决方案是逐行读取文件，并将每一行存储到一个变量(或数组，或您需要的内容)中。在阅读时，您可以通过以下方式检查该行是否为空行：

String newline = System.getProperty("line.separator"); // this is for getting proper new line;

boolean isNewline = myLine.startsWith(newline); //if your line start with newLine symbol

如果isNewLine为真，那么您可以设置一个标志，如果下一行再次为空，那么您就找到了您的段落。

Answer 2

使用正则表达式的String#split()应该可以工作。

例如：

String[] paragraphs = input.split("\\n\\n\\n");

注意:这只适用于Unix换行符。

Answer 3

这可以通过简单的正则表达式来完成：

尝试：

 String[] paragraphs = text.split("(?im)(\r?\n){3,}");

其中变量text包含您的数据。基于样本输入数据，上面的语句将其分为3个部分。此解决方案适用于在Windows或Linux上创建的文件，因此与平台无关。