排列组合 查找出所有号码的组合情况

package com.test;

import java.util.Iterator;
import java.util.LinkedList;

public class Test {
    private LinkedList<String> list = new LinkedList<String>();
    private void PaiLie(String startStr, String str) {
            for (int i = 0; i < str.length(); i++) {
                for (int j = i + 1; j < str.length(); j++) {
                 char[] ch = str.toCharArray();
                    char temp = ch[i];
                    ch[i] = ch[j];
                    ch[j] = temp;
                    String startStr1 = startStr + String.valueOf(ch[0]);
                    String s = (new String(ch)).substring(1,(new String(ch)).length());
                    if ((!list.contains(startStr1 + s)) ){
                     list.add(startStr1 + s);
                    }
                    PaiLie(startStr1, s);
                }
            }
    }
    /**
     * 打印
     */
    private void display() {
        Iterator<String> it = list.listIterator();
        while (it.hasNext()) {
            System.out.println(it.next().toString());
        }
    }

    public static void main(String[] args) throws InterruptedException {
            Test test = new Test();
            test.PaiLie("","123");
            test.display();
    }
}