在最后一次出现字符后删除字符串

Question

在我的应用程序中,我附加一个字符串来创建生成URL的路径.现在我想在按下后退按钮时删除附加的字符串.

假设这是字符串:

/String1/String2/String3/String4/String5

现在我想要一个这样的字符串:

/String1/String2/String3/String4/

我怎样才能做到这一点？

Answer 1

您可以使用lastIndexOf()相同的方法

if (null != str && str.length() > 0 )
{
    int endIndex = str.lastIndexOf("/");
    if (endIndex != -1)  
    {
        String newstr = str.substring(0, endIndex); // not forgot to put check if(endIndex != -1)
    }
}  

Answer 2

String whatyouaresearching = myString.substring(0, myString.lastIndexOf("/"))

Answer 3

您可以使用空安全的org.apache.commons.lang3.StringUtils.substringBeforeLast。

从javadoc：

// The symbol * is used to indicate any input including null.
StringUtils.substringBeforeLast(null, *)      = null
StringUtils.substringBeforeLast("", *)        = ""
StringUtils.substringBeforeLast("abcba", "b") = "abc"
StringUtils.substringBeforeLast("abc", "c")   = "ab"
StringUtils.substringBeforeLast("a", "a")     = ""
StringUtils.substringBeforeLast("a", "z")     = "a"
StringUtils.substringBeforeLast("a", null)    = "a"
StringUtils.substringBeforeLast("a", "")      = "a"

Maven 依赖：

// The symbol * is used to indicate any input including null.
StringUtils.substringBeforeLast(null, *)      = null
StringUtils.substringBeforeLast("", *)        = ""
StringUtils.substringBeforeLast("abcba", "b") = "abc"
StringUtils.substringBeforeLast("abc", "c")   = "ab"
StringUtils.substringBeforeLast("a", "a")     = ""
StringUtils.substringBeforeLast("a", "z")     = "a"
StringUtils.substringBeforeLast("a", null)    = "a"
StringUtils.substringBeforeLast("a", "")      = "a"