java 集合输出所有组合结果

public static void main(String[] args) {            //定义数组            String[] strs={"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};           //定义随机组合最多位数           int size=5;           eachStr(size,strs);//调用       }       public static void pintStr(int num,String[] strs,String beforeStr,String beforeChar){           num--;           for(int i=0;i<strs.length;i++){               if(strs[i].equals(beforeChar)){                   continue;               }               if(num==0){                   System.out.PRintln((beforeStr==null?"":beforeStr)+strs[i]);               }else{                  pintStr(num,strs,(beforeStr==null?"":beforeStr)+strs[i],strs[i]);               }          }       }       public static void eachStr(int num,String[] strs){	    while (num>0) {	        pintStr(num, strs, null,null);               num--;            }       }