慕无忌6386368
2016-04-20 20:15
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();
}
}
public class Course {
public String id;
public String name;
public Course(String id, String name) {
this.id = id;
this.name = name;
}
先导入import java.util.ArrayList;
然后你在 package 课程选择 包下新建一个Course类
然后就ok啦~~
太粗心了吧~报错的地方是在添加3,4的地方,应该是addAll而不是add
Course[] courses={new Course("3","离散数学"),new Course("4","汇编语言")};
coursesToSelect.addAll(Arrays.asList(courses));
Java入门第三季
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