Java 去掉字符串中空格:
package com.string.to;package com.string.to;public class Thirth {public static void main(String args[]){String s="a 1 b 2 c 3 d 4 a1b2c3d4";String t=s.replaceAll("\\s{1,}", "");System.out.println(t);String g=s.replaceFirst("a", "A");System.out.println(g);String h=s.replaceAll("\\d", "*");System.out.println(h);String j=s.replaceAll("a", "X");System.out.println(j);}}