java - Android '\' special character

Question

I have an android application where I have to find out if my user entered the special character '\' on a string. But i'm not obtaining success by using the string.replaceAll() method, because Java recognizes \ as the end of the string, instead of the " closing tag. Does anyone have suggestions of how can I fix this? Here is an example of how I tried to do this:

private void ReplaceSpecial(String text) {
     if (text.trim().length() > 0) {
    text = text.replaceAll("\", "%5C");
}

It does not work because Java doesn't allow me. Any suggestions?

Answer 1

Try this: You have to use escape character '\'

text = text.replaceAll("\\\\", "%5C");

Answer 2

尝试

text = text.replaceAll("\\\\", "%5C");

replaceAll使用正则表达式语法 where\是特殊字符，因此您需要对其进行转义。为此，您需要传递\\给正则表达式引擎，但要创建表示正则表达式的字符串，\\您需要将其写为"\\\\"（\也是 String 中的特殊字符，每个都需要另一个转义\）

---

为了避免这种正则表达式混乱，您可以使用replace正在处理文字的

text = text.replace("\\", "%5C");

Answer 3

text = text.replaceAll("\", "%5C");

Should be:

text = text.replaceAll("\\\\", "%5C");

Why?

Since the backward slash is an escape character. If you want to represent a real backslash, you should use double \ (\\)

Now the first argument of replaceAll is a regular expression. So you need to escape this too! (Which will end up with 4 backslashes).

Alternatively you can use replace which doesn't expect a regex, so you can do:

text = text.replace("\\", "%5C");

Answer 4

第一个参数 toreplaceAll被解释为正则表达式，因此您实际上需要四个反斜杠：

text = text.replaceAll("\\\\", "%5C");

字符串文字中的四个反斜杠表示实际中的两个反斜杠String，这反过来表示匹配单个反斜杠字符的正则表达式。

或者，按照Pshemo的建议，使用replace而不是，它将其第一个参数视为文字字符串而不是正则表达式。replaceAll

Answer 5

首先，由于“\”是 Java 中的转义字符，因此您需要使用两个反斜杠来获得一个反斜杠。其次，由于 replaceAll() 方法将正则表达式作为参数，因此您还需要转义该反斜杠。因此，您需要使用

text = text.replaceAll("\\\\", "%5C");

Answer 6

我可能会迟到，但并非最不重要。

添加\\\\以下正则表达式以启用\.

示例正则表达式：

private val specialCharacters = "-@%\\[\\}+'!/#$^?:;,\\(\"\\)~`.*=&\\{>\\]<_\\\\"
private val PATTERN_SPECIAL_CHARACTER = "^(?=.*[$specialCharacters]).{1,20}$"

希望能帮助到你。