Crouse[] crouse={new Crouse("2","语文"),new Crouse("3","数学")};

  coursestoselect.addAll(Arrays.asList(crouse));

  Crouse temp2=(Crouse)coursestoselect.get(2);

  Crouse temp3=(Crouse)coursestoselect.get(3);

  System.out.print("添加了课程："+temp2.id+":"+temp2.name+"\n"+"添加了课程："+temp3.id+":"+temp3.name+"\n");

  Crouse[] crouse2={new Crouse("4","大文"),new Crouse("5","大学")};

  coursestoselect.addAll(Arrays.asList(2,crouse2));

  Crouse temp4=(Crouse)coursestoselect.get(2);

  Crouse temp5=(Crouse)coursestoselect.get(3);

  System.out.print("添加了课程："+temp4.id+":"+temp4.name+"\n"+"添加了课程："+temp5.id+":"+temp5.name+"\n");

   }
2次输出的结果是一样的，第二个数组里面的根本就没有插入到列表啊？