java字符排序_如何按字母顺序对字符串进行排序java

如果先将字符放入数组中,则可以使用Arrays.sort执行此操作. (它必须是Character对象的数组而不是char基元,以便使用自定义的不区分大小写的比较器.)

// put the characters into an array

Character[] chars = new Character[str.length()];

for (int i = 0; i < chars.length; i++)

chars[i] = str.charAt(i);

// sort the array

Arrays.sort(chars, new Comparator() {

public int compare(Character c1, Character c2) {

int cmp = pare(

Character.toLowerCase(c1.charValue()),

Character.toLowerCase(c2.charValue())

);

if (cmp != 0) return cmp;

return pare(c1.charValue(), c2.charValue());

}

});

// rebuild the string

StringBuilder sb = new StringBuilder(chars.length);

for (char c : chars) sb.append(c);

str = sb.toString();