java_去除字符串中的空格的几种方法

/** *  */package 作业0919;import java.util.regex.Matcher;import java.util.regex.Pattern;public class 去除空格 {public static void main(String[] args) {String string = "aa bb     cc   dd";String string1 = "";// 方法一:String string2 = string.replaceAll(" ", "");System.out.println(string2);// 方法二:for (int i = 0; i < string.length(); i++) {if (!String.valueOf(string.charAt(i)).equals(" ")) {string1 += string.charAt(i);}}System.out.println(string1);// 方法三:String regex = "\\s";String[] string3 = string.split(regex);String string4 = "";for (int i = 0; i < string3.length; i++) {string4 += string3[i];}System.out.println(string4);System.out.println("************");Matcher matcher = Pattern.compile(regex).matcher(string);while (matcher.find()) {System.out.println(matcher.group());}}}