java 自带的排序工具

import java.util.Arrays;

import java.util.Collections;

import java.util.List;

/**

 * <p>

 * <code>TT</code>

 * </p>

 * Description:

 *

 * @author Mcchu

 * @date 2017/12/8 10:43

 */

public class TT {

    /**

     * 正序

     *

     * 利用 jdk 自带排序工具

     */

    private static void positiveSequence(){

        System.out.println("正序排列数字数组：");

        Integer[] intArr = new Integer[]{3,6,2,1,6,7,24,7};

        Arrays.sort(intArr);

        for (Integer in: intArr){

            System.out.print(in);

            System.out.print(",");

        }

        System.out.println("\n正序排列字符串数组：");

        String[] arr1 = new String[]{"f","2","c","e","3","d","1","a","b","back"};

        Arrays.sort(arr1);

        for (String str: arr1){

            System.out.print(str);

            System.out.print(",");

        }

        System.out.println("\n正序排列List集合：");

        String[] arr2 = new String[]{"f","2","c","e","3","d","1","a","b","back"};

        List list = Arrays.asList(arr2);

        Collections.sort(list);

        for (String str: arr2){

            System.out.print(str);

            System.out.print(",");

        }

        System.out.println();

    }

    /**

     * 反序

     *

     * 利用字符串反转

     */

    private static void reverse(){

        StringBuffer sb = new StringBuffer();

        String s = "a,b,c,d,e,f,g";

        sb.append(s);

        sb.reverse();

        System.out.println(sb.toString());

    }

    public static void main(String[] args) {

        System.out.println("正序");

        positiveSequence();

        System.out.println("\n反序");

        reverse();

    }

}