正则表达式找到＆amp;替换特定的子串

Question

我想要正则表达式找到＆amp;将以下给定字符串中的第一个和第三个csv单词替换为单词rownum。

NONE

我尝试过以下正则表达式，但在String str = "select dummy,rownum,rowid as \"rownum\",rownum as order_number from dual"; 字词之前或之后替换了逗号,

rownum

实际输出：str = str.replaceAll("(?i)[^\"A-Z0-9]rownum[^$\"A-Z0-9]"," NONE ")

预期输出：select dummy NONE rowid as "rownum" NONE as order_number from dual

Answer 1

如果您希望避免替换"rownum"，因为它被"包围，那么您可以使用look-around机制禁止"之前或之后

String str = "select dummy,rownum,rowid as \"rownum\",rownum as order_number from dual";
str = str.replaceAll("(?i)(?!<\")\\brownum\\b(?!\")"," NONE ");
System.out.println(str);

输出：select dummy, NONE ,rowid as "rownum", NONE as order_number from dual

但该解决方案仅对此特定情况有效。如果你有其他的，你应该搜索SQL解析器而不是RegEx。

Answer 2

你可以试试这个，它的作品

str = str.replace("rownum", "NONE");
str = str.replace("\"NONE\"", "\"rownum\"");