JAVA正则表达式替换，替换不成功

str = "D:\code\erp\target\class\artifacts\erp_war_exploded\/attachment/image/seal/4//5858.png"
我想把str的\/和//都替换成/
String REGEX = "\/|//";
Pattern p = Pattern.compile(REGEX);
Matcher m = p.matcher(str);
str=m.replaceAll("/");

这样写为什么不行？？该怎么搞？

     String str ="D:\\code\\erp\\target\\class\\artifacts\\erp_war_exploded\\/attachment/image/seal/4//5858.png";
     System.out.println(str);
        //   我想把str的\/和//都替换成/
    String REGEX = "\\\\/|//";
    Pattern p = Pattern.compile(REGEX);
    Matcher m = p.matcher(str);
    str=m.replaceAll("/");
    System.out.println(str);

        运行结果：
        D:\code\erp\target\class\artifacts\erp_war_exploded\/attachment/image/seal/4//5858.png
  D:\code\erp\target\class\artifacts\erp_war_exploded/attachment/image/seal/4/5858.png