在Java-11及以上版本中，可以使用String。strip API返回值为该字符串的字符串，删除所有前导和尾随空格。相同的javadoc代码如下:

/**
 * Returns a string whose value is this string, with all leading
 * and trailing {@link Character#isWhitespace(int) white space}
 * removed.
 * <p>
 * If this {@code String} object represents an empty string,
 * or if all code points in this string are
 * {@link Character#isWhitespace(int) white space}, then an empty string
 * is returned.
 * <p>
 * Otherwise, returns a substring of this string beginning with the first
 * code point that is not a {@link Character#isWhitespace(int) white space}
 * up to and including the last code point that is not a
 * {@link Character#isWhitespace(int) white space}.
 * <p>
 * This method may be used to strip
 * {@link Character#isWhitespace(int) white space} from
 * the beginning and end of a string.
 *
 * @return  a string whose value is this string, with all leading
 *          and trailing white space removed
 *
 * @see Character#isWhitespace(int)
 *
 * @since 11
 */
public String strip()

这些例子可以是:——

System.out.println("  leading".strip()); // prints "leading"
System.out.println("trailing  ".strip()); // prints "trailing"
System.out.println("  keep this  ".strip()); // prints "keep this"

在Java-11及以上版本中，可以使用String。strip API返回值为该字符串的字符串，删除所有前导和尾随空格。相同的javadoc代码如下:

/**
 * Returns a string whose value is this string, with all leading
 * and trailing {@link Character#isWhitespace(int) white space}
 * removed.
 * <p>
 * If this {@code String} object represents an empty string,
 * or if all code points in this string are
 * {@link Character#isWhitespace(int) white space}, then an empty string
 * is returned.
 * <p>
 * Otherwise, returns a substring of this string beginning with the first
 * code point that is not a {@link Character#isWhitespace(int) white space}
 * up to and including the last code point that is not a
 * {@link Character#isWhitespace(int) white space}.
 * <p>
 * This method may be used to strip
 * {@link Character#isWhitespace(int) white space} from
 * the beginning and end of a string.
 *
 * @return  a string whose value is this string, with all leading
 *          and trailing white space removed
 *
 * @see Character#isWhitespace(int)
 *
 * @since 11
 */
public String strip()

这些例子可以是:——

System.out.println("  leading".strip()); // prints "leading"
System.out.println("trailing  ".strip()); // prints "trailing"
System.out.println("  keep this  ".strip()); // prints "keep this"

private void capitaliseEveryWordInASentence() {

    String mm = "Hello there, this is the cluster";

    String[] words = mm.split(" ");
    String outt = "";

    for (String w : words) {

        outt = outt + Character.toUpperCase(w.charAt(0)) + w.substring(1) + " ";
    }

    System.out.println(outt.trim());
}

S.strip()你可以从Java 11开始使用。

S.trim()你可以使用。

Trim()是你的选择，但如果你想使用replace方法——这可能更灵活，你可以尝试以下方法:

String stripppedString = myString.replaceAll("(^ )|( $)", "");

您可以尝试trim()方法。

String newString = oldString.trim();

看一下javadocs