Java String replaceAll - 以奇怪的方式为 \

Question

我有这样的字符串：

My word is "I am busy" message

现在，当我将此字符串分配给 pojo 字段时，我得到的转义如下：

String test = "My word is \"I am busy\" message";

我有一些其他数据，我想用上面的字符串替换其中的内容：

假设我的基本字符串是：

String s = "There is some __data to be replaced here";

现在当我使用 replaceAll 时：

String s1 = s.replaceAll("__data", test);
System.out.println(s1);

这 returns 我的输出为：

There is some My word is "I am busy" message to be replaced here

为什么我替换后没有出现“\”。我需要转义 2 次吗？

还有这样使用的时候:

String test = "My word is \\"I am busy\\" message";

然后它也给出与 :

相同的输出

There is some My word is "I am busy" message to be replaced here

我的预期输出是：

There is some My word is \"I am busy\" message to be replaced here

Answer 1

您需要使用四个反斜杠来打印一个反斜杠。

String test = "My word is \\\"I am busy\\\" message";
String s = "There is some __data to be replaced here";
System.out.println(s.replaceAll("__data", test));

或

String test = "My word is \"I am busy\" message";
String s = "There is some __data to be replaced here";
System.out.println(s.replaceAll("__data", test.replace("\"", "\\\"")));

输出：

There is some My word is \"I am busy\" message to be replaced here

Answer 2

试试这个：

String test = "My word is \\\"I am busy\\\" message";
String s = "There is some __data to be replaced here";
System.out.println(s.replaceAll("__data", test));

要在输出中获得 \，您需要使用 \\\

来自docs：

Note that backslashes () and dollar signs ($) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see Matcher.replaceAll. Use Matcher.quoteReplacement(java.lang.String) to suppress the special meaning of these characters, if desired.

所以你可以使用 Matcher.quoteReplacement(java.lang.String)

String test = "My word is \"I am busy\" message";
String s = "There is some __data to be replaced here";
System.out.println(s.replaceAll("__data", test), Matcher.quoteReplacement(test));

Java String replaceAll - 以奇怪的方式为 \

Java String replaceAll - works in a wierd way for \

java

string

replaceall