排序的hashmap（guava）

Builder<String, String> b2 = ImmutableSortedMap.naturalOrder();
b2.put("sta_1111", "sta_1111");
b2.put("sta_2222", "sta_2222");
        b2.put("sys_1123", "sys_1123");
        b2.put("sta_1122", "sta_1122");
        b2.put("sys_1122", "sys_1122");
ImmutableSortedMap<String, String> map = b2.build();
        for(Entry<String, String> entry : map.entrySet()) {
            System.out.println(entry.getKey());
        }