package com_imooc_collection; /* * 备选课程类 * */ import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class ListTest { /* * 用于存放备选课程的list * */ public List coursesToSelect; public ListTest() { this.coursesToSelect=new ArrayList(); } //用于往coursesToSelect中添加备选课程 public void testAdd(){ //创建爱你一个课程对象,并通过调用add方法,添加到备选课程 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); /*Course cr3= new Course("3","test"); coursesToSelect.add(2,cr3); Course temp3= (Course)coursesToSelect.get(0); System.out.println("添加了课程"+temp3.id+":"+temp3.name);*/ Course[] course ={new Course("3","离散数学"),new Course("4","汇编语言")}; coursesToSelect.addAll(Arrays.asList(course)); Course temp3 = (Course) coursesToSelect.get(2); Course temp4 = (Course) coursesToSelect.get(3); System.out.println("添加了两门课程:"+temp3.id+":"+temp3.name+";"+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("添加了两门课程:"+temp5.id+";"+temp5.name+";"+temp6.id+":"+temp6.name); /* * 取得list中的元素的方法 * */ public void HY(){ //此处报错,提示缺少分号 int size = coursesToSelect.size(); System.out.println("有如下课程待选:"); 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[] arg) { ListTest lt=new ListTest(); lt.testAdd(); // lt.testGet(); } }
已经解决了,上一个方法的大括号位置错了