好心累，真的是。。打完了一样也有错= = 求大神

package 课程选择;

import java.util.List;

public class ListTest {

public List coursesToSelect;

public ListTest()

{

this.coursesToSelect=new ArrayList();

}

/*用于往coursesToSelect中添加备选课程*/

public void testAdd(){

//创建一个课程对象，并通过调用add方法，添加到备选课程List中

Course cr1=new Course("1","数据结构");

coursesToSelect.add(cr1);

Course temp=(Course)coursesToSelect.get(0);

System.out.println("添加了课程"+temp.id+":"+temp.name);

Course cr2=new Course("2","C语言");

coursesToSelect.add(0,cr2);

Course temp2=(Course)coursesToSelect.get(0);

System.out.println("添加了课程"+temp2.id+":"+temp2.name);

/*以下方法会抛出数组下标越界异常

Course cr3=new Course("3","List");

coursesToSelect.add(4,cr3);*/

Course[] course={new Course("3","离散数学"),new Course("4","汇编语言")};

coursesToSelect.add(Arrays.asList(course));

Course temp3=(Course)coursesToSelect.get(2);

Course temp4=(Course)coursesToSelect.get(3);

System.out.println("添加了课程"+temp3.id+":"+temp3.name);

System.out.println("添加了课程"+temp4.id+":"+temp4.name);

Course[] course2={new Course("5","高等数学"),new Course("6","大学英语")};

coursesToSelect.addAll(2,Arrays.asList(course2));

Course temp5=(Course)coursesToSelect.get(2);

Course temp6=(Course)coursesToSelect.get(3);

System.out.println("添加了课程"+temp5.id+":"+temp5.name);

System.out.println("添加了课程"+temp6.id+":"+temp6.name);

}

//取得List 中的元素方法

public void testGet(){

int size=coursesToSelect.size();

System.out.println("有如下课程可以选择：");

for(int i=0;i<size;i++)

{

Course cr=(Course)coursesToSelect.get(i);

System.out.println("课程："+cr.id+":"+cr.name);

}

}

public static void main(String args[])

{

ListTest It=new ListTest();

It.testAdd();

It.testGet();

}

}