求个java的正则表达式

public class Regular{

public static void main(String[]args){

//把字符串中的 "aaa"全部替换为"z" 打印zbzcz

System.out.println("aaabaaacaaa".replaceAll("a{3}","z"));

//把字符串的"aaa","aa"或者"a" 全部替换为"*" 打印*b*c*

System.out.println("aaabaaca".replaceAll("a{1,3},"\\*"));

//把字符串中的数字全部替换为"z" 打印zzzazzbzzcc

System.out.println("123a44b35cc".replaceAll("\ \d","z"));

//把字符串中的非数字全部替换为"0" 打印1234000435000

System.out.println("1234abc435def".replaceAll("\ \D","0"));

//把字符串中的"."全部替换为"\"打印abc\def\ghi\jk

System.out.println("abc.def.ghi.jk".replaceAll("\\.","\\\\"));

//把字符串中的"a.b"