检查字符串是否包含\n Java

Question

如何检查字符串是否包含\n或新行字符？

word.contains("\\n")
word.contains("\n")

Answer 1

如果字符串是在同一个程序中构建的,我建议使用它:

String newline = System.getProperty("line.separator");
boolean hasNewline = word.contains(newline);

但是如果你打算使用\n,这个驱动程序说明了该做什么:

class NewLineTest {
    public static void main(String[] args) {
        String hasNewline = "this has a newline\n.";
        String noNewline = "this doesn't";

        System.out.println(hasNewline.contains("\n"));
        System.out.println(hasNewline.contains("\\n"));
        System.out.println(noNewline.contains("\n"));
        System.out.println(noNewline.contains("\\n"));

    }

}

导致

true
false
false
false

在回应你的评论:

class NewLineTest {
    public static void main(String[] args) {
        String word = "test\n.";
        System.out.println(word.length());
        System.out.println(word);
        word = word.replace("\n","\n ");
        System.out.println(word.length());
        System.out.println(word);

    }

}

结果是

6
test
.
7
test
 .

Answer 2

为了便于携带,你真的应该做这样的事情:

public static final String NEW_LINE = System.getProperty("line.separator")
.
.
.
word.contains(NEW_LINE);

除非你绝对确定这"\n"是你想要的.

Answer 3

第二个:

word.contains("\n");