Java字符串用&替换'&' 但不是 & 到 &
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Java String Replace '&' with & but not & to &
提问by sribasu
I have a large String in which I have & characters used available in following patterns -
我有一个大字符串，其中有 & 字符可用于以下模式 -
A&B
A & B
A& B
A &B
A&B
A & B
A& B
A &B
I want to replace all the occurrences of & character to &While replacing this, I also need to make sure that I do not mistakenly convert an &to &. How do I do that in a performance savvy way? Do I use regular expression? If yes, please can you help me to pickup the right regular expression to do the above?
我想将所有出现的 & 字符&替换为在替换它时，我还需要确保我没有错误地将 an 转换&为&. 我如何以精通性能的方式做到这一点？我使用正则表达式吗？如果是，请您帮我选择正确的正则表达式来执行上述操作吗？
I've tried following so far with no joy:
到目前为止，我一直没有高兴地尝试以下操作：
data = data.replace(" & ", "&"); // doesn't replace all &
data = data.replace("&", "&"); // replaces all &, so & becomes &
采纳答案by khampson
You can use a regular expression with a negative lookahead.
您可以使用带有否定前瞻的正则表达式。
The regex string would be &(?!amp;).
正则表达式字符串将是&(?!amp;).
Using replaceAll, you would get:
使用replaceAll，你会得到：
A&B
A & B
A& B
A &B
A&B
A & B
A& B
A &B
So the code for a single string strwould be:
所以单个字符串的代码str将是：
str.replaceAll("&(?!amp;)", "&");
回答by gleba
You can try this, it should work:
你可以试试这个，它应该可以工作：
data = data.replaceAll("&","&").replaceAll("&","&");
That way you first replace all &with &so all you'll have is &, and then, you replace all of them with &.
这样，您首先将所有内容替换为&，&因此您将拥有的只是&，然后，您将所有内容替换为&。
