如何找到String.indexOf（“ \\”）？

Question

I need to get the substring that appears before a bunch of \\r\\n\\r\\n junk. So I want to geto the first /that appears. indexOf("\\") is not accepted. String.indexOf("\\") does not match the first . ????? Thanks

Answer 1

If you're looking for the first occurrence of \\n in a string then searching for \\\\ won't help. You need to look for \\n .

String.indexOf("\n")

Note that \\n is one character, not two. It's an escape sequence that evaluates to the character with ASCII value 10.

Answer 2

String s1 = "LINE1\r\n\r\nLINE2";
Matcher matcher = Pattern.compile(".+").matcher(s1);
if (matcher.find()) {
    System.out.println(matcher.group());
} else {
    System.out.println("String contains no character other than \\n and \\r");
}

or a bit more perverted:

String s1 = "LINE1\r\n\r\nLINE2";
BufferedReader br = new BufferedReader(new StringReader(s1));
try {
    System.out.println(br.readLine());
} finally {
    br.close();
}

Output in both cases: LINE1

Answer 3

indexOf("/") 

should work fine. Why do you say it is not?

Answer 4

Works fine for me:

System.out.println( "abc//def//".indexOf("/") );

Post your SSCCE demonstrating the problem.

Answer 5

Why does indexOf('/') not work? Does it return the wrong index? Forward slashes should be fine -- backward slashes ( \\ ) are escape characters.

Answer 6

如果您要查找'\\'，请使用.indexOf（“ \\”）;