全排列处理接口    

public interface PermutationProcessor<T> {      void process(T[]array);  }  

全排列类    

public final class FullPermutation {        public  static <T> void permutate(T a[], PermutationProcessor<T> processor) {          permutate(a, 0, a.length,processor);        }     static <T>  void permutate(T a[], int m, int n,PermutationProcessor<T> processor) {          int i;          T t;          if (m < n - 1) {              permutate(a, m + 1, n,processor);              for (i = m + 1; i < n; i++) {                  swap(a, m, i);                  permutate(a, m + 1, n,processor);                  swap(a, m, i);              }          } else {              processor.process(a);          }      }        private static <T> void swap(T[] a, int m, int i) {          T t;          t = a[m];          a[m] = a[i];          a[i] = t;      }  }

[代码]调用示例    

    public static void main(String[] args) {          Integer[] a={1,2,4};          FullPermutation.permutate(a, new PermutationProcessor<Integer>() {              @Override              public void process(Integer[] array) {                  for(int i:array){                      System.out.printf("%d ",i);                  }                  System.out.println();              }          });      }  

[代码]运行结果    

1 2 4   1 4 2   2 1 4   2 4 1   4 2 1   4 1 2