arraylist排序方法根据某个字段排序,arraylist排序函数

今天发现，ArrayList 排序不满足期望。

起先，List是这样Before sort: [1, @I, am, Love, java, very, Much]

使用Collections.sort()方法排后是这样

After sort: [1, @I, Love, Much, am, java, very]

顺序：数字-非数字和字母字符-大写字符串（A-Z）-小写字符串（a-z）

期望的是按照字母顺序，忽略大小写

After override sort method: [1, @I, am, java, Love, Much, very]

所以只能Override sort方法

ArrayList<String> list=new ArrayList<String>(); list.add("1"); list.add("@I"); list.add("am"); list.add("Love"); list.add("java"); list.add("very"); list.add("Much"); System.out.println("Before sort: "+list); Collections.sort(list); System.out.println("After sort: "+list); Collections.sort(list,new Comparator<Object>(){ @Override public int compare(Object obj1, Object obj2) { return ((String) obj1).toUpperCase().compareTo(((String) obj2).toUpperCase()); } }); System.out.println("After override sort method: "+list); Collections.reverse(list); System.out.println("After reverse: "+list);

 运行结果如下：

Before sort: [1, @I, am, Love, java, very, Much]
After sort: [1, @I, Love, Much, am, java, very]
After override sort method: [1, @I, am, java, Love, Much, very]
After reverse: [very, Much, Love, java, am, @I, 1]