java知識點

1、實現list集合逆序排列

Collections.reverse(list);

2、將數組轉化爲String

StringBuilder sb = new StringBuilder();
String[] str = {“a”,”b”,”c”,”d”,”e”};
for (int i = 0; i < str.length; i++) {
sb.append(str[i]+”/”);
}
return sb.toString();

3、將list轉化爲String，每個元素用“/”隔開，去除最後的“/”

StringBuilder sb = new StringBuilder();
for (int j = 0; j < list.size(); j++) {
sb.append(list.get(j)+”/”);
}

return sb.toString().substring(0, sb.length()-1);