java - 替换字符串中的字符序列不起作用

Question

我正在从 URL 检索数据到字符串 a，并将该字符串作为参数传递给 gson 的 fromJson 方法。现在我需要替换字符串 a 中的一些子字符串。

    String url = "abc";
    String a = getDataFromURL(url); //this string contains all the data from the URL, and getDataFromURL is the method that reads the data from the URL.
    String tmp = "\"reservation\":\"www.\"";
    String tmpWithHttp = "\"reservation\":\"http://www.\"";

    if(a.contains(tmp))
    {
    a = a.replace(a, tmpWithHttp);
    }

URL 中的所有数据都是 JSON。我在这里的要求是，如果字符串 a 包含子字符串 - "reservation":"www.，请将其替换为"reservation":"http://www.

我上面的代码不起作用。有人可以在这里帮助我吗？

Answer 1

你可能的意思是：

a = a.replace(tmp, tmpWithHttp);

代替：

a = a.replace(a, tmpWithHttp);

而且您无需contains()在更换前进行检查。String#replace仅当要替换的子字符串存在时，方法才会替换。因此，您可以删除周围的if.

Answer 2

In your question, you specify that you want to replace "reservation":"www.. However, in your code, you've added an extra escaped quote, causing the replacement to search for "reservation":"www.", which isn't present in the string.

Simply remove that last escaped quote:

String tmp = "\"reservation\":\"www.";