Java string removes whitespace and null characters at both ends

String in Java has a trim () that removes the front and back spaces of a string.
However, trim () removes only the half-width spaces in the string, not the full-width spaces.
Removing the full-width space requires some judgment on the basis of the trim () method.
String textcontent = "Abctest";
Textcontent = Textcontent.trim ();
while (Textcontent.startswith ("")) {//Here is judged to be an all-width space
Textcontent = textcontent.substring (1, Textcontent.length ()). Trim ();
}
while (Textcontent.endswith ("")) {
textcontent = textcontent.substring (0, Textcontent.length ()-1). Trim ();
}

Java string removes whitespace and null characters at both ends