Question

我有一个表达式字符串

"((firstname = john AND Lastname = Eleven) OR (salary = 15000 AND location = Mexico OR (firstname = mathew AND lastname = Thirteen)))";

是否有任何内置函数我可以将它们拆分为List<String>，格式如下：

list[0] = "(";
list[1] = "(";
list[2] = "firstname";
list[3] = "=";
list[4] = "john"
list[5] = "AND";
list[6] = "Lastname"
list[7] = "=";
list[8] = "Eleven";
list[9] = ")"
list[10] = "OR"
list[11] = "(";
list[12] = "salary";
list[13] = "15000"
list[14] = "AND"
etc...

Answer 1

您可以替换所有(或) woth space $1 space，然后用空格分割：

String spl[] = 
       str.replaceAll("([\\(\\)=])", " $1 ").replaceAll(" +", " ").trim().split("\\s");

<强>输出

(, (, firstname, =, john, AND, Lastname, =, Eleven, ), OR, (, salary, =, 15000, AND, 
location, =, Mexico, OR, (, firstname, =, mathew, AND, lastname, =, Thirteen, ), ), )

Answer 2

只需将split与多个分隔符

一起使用即可

String[] tokens = exp.split("\\(|\\)| |=");

Answer 3

通常，此过程称为lexical analysis：

在计算机科学中，词法分析是将一系列字符（例如在计算机程序或网页中）转换为的过程令牌（具有指定且因此标识的含义的字符串）

可以定义lexical grammar：

词汇语法是一种形式语法定义标记的语法

一旦定义了词汇语法，就可以使用像JavaCC或JFlex这样的工具，在词法分析器中转换该语法，这基本上是一个软件，它将一系列字符作为输入，并生成一个令牌列表作为输出。

请注意，词法分析器不仅会在字符串序列中分割原始的字符序列，而且会在更具体的标记序列中分割，例如：

OPEN_PARANTHESIS OPEN_PARANTHESIS NAME with value firstname OPERATOR with value = NAME with value john OPERATOR with value AND NAME with value Lastname OPERATOR with value = ...

所以它做的比你提出的更多，但你的问题似乎与它有关。

Answer 4

您可以将lookahead和lookbehind与regex一起使用来获取令牌并对其进行迭代，例如：

String s = "((firstname = john AND Lastname = Eleven) OR (salary = 15000 AND location = Mexico OR (firstname = mathew AND lastname = Thirteen))";
for(String token : s.split("((?=(\\(|\\)|\\=|\\sAND\\s|\\sOR\\s))|(?<=(\\(|\\)|\\=|\\sAND\\s|\\sOR\\s)))")){
    System.out.println(token.trim());
}

Answer 5

"((firstname = john AND Lastname = Eleven) OR (salary = 15000 AND location = Mexico OR (firstname = mathew AND lastname = Thirteen)))";

在“((”之间添加如下空格：

String exp = "( ( firstname = john AND Lastname = Eleven ) OR ( salary = 15000 AND location = Mexico OR ( firstname = mathew AND lastname = Thirteen ) ) )";

现在您可以使用exp.split( " ");

进行拆分

将表达式String拆分为ArrayList

5 个答案: