感覺最后多了個 }

你把testForEachForSet方法放到main方法前面試試

package?com.test.collection;

import?java.util.ArrayList;
import?java.util.Arrays;
import?java.util.List;
import?java.util.Scanner;

public?class?SetTest?{

????public?List<Course>?coursesToSelect;
????//構造器
????public?SetTest(){
????????coursesToSelect=new?ArrayList<Course>();
????}

/*????public?static?class?List_Test?{
????????//用于存放備選課程的List
????????public?List?coursesToSelect;

????????public?List_Test(){
????????????this.coursesToSelect=new?ArrayList();
????????}
????????}*/
????????//用于網coursesToSelet中添加備選課程
????????public?void?testAdd(){
????????????//創建一個課程對象，并通過調用add方法，添加到備選課程中
????????????Course?cr1=new?Course("1","數據結構");
????????????coursesToSelect.add(cr1);
????????????Course?temp=?(Course)?coursesToSelect.get(0);
????????????//System.out.println("添加了課程："+temp.id+";"+temp.name);


????????????Course?cr2=new?Course("2","C語言");
????????????coursesToSelect.add(0,cr2);
????????????Course?temp2=?(Course)?coursesToSelect.get(0);
????????????//System.out.println("添加了課程："+temp2.id+";"+temp2.name);

????????????//coursesToSelect.add(cr1);
????????????//Course?temp0=?(Course)?coursesToSelect.get(2);
????????????//System.out.println("添加了課程："+temp.id+";"+temp.name);

????????????//下面方法會拋出數組下標越界異常
????????????//?Course?cr3=new?Course("3","test");
????????????//coursesToSelect.add(4,cr3);

????????????Course[]?courses={new?Course("3","離散數學"),new?Course("4","匯編語言")};
????????????coursesToSelect.addAll(Arrays.asList(courses));
????????????Course?temp3=?(Course)?coursesToSelect.get(3);
????????????Course?temp4=?(Course)?coursesToSelect.get(4);

????????????//System.out.println("添加了兩門課程："+temp3.id+";"+temp.name+";"+temp4.id+";"+temp4.name);

????????????Course[]?courses2={new?Course("5","高等數學"),new?Course("6","大學英語")};
????????????coursesToSelect.addAll(2,Arrays.asList(courses2));
????????????Course?temp5=?(Course)?coursesToSelect.get(2);
????????????Course?temp6=?(Course)?coursesToSelect.get(3);
????????????//System.out.println("添加了兩門課程："+temp5.id+";"+temp5.name+";"+temp6.id+";"+temp6.name);

????????}


????????/*
????????for?each方法訪問集合元素??更好
?????????*/
????????public?void?testForEach(){
????????????System.out.println("有如下課程待選（通過foreach訪問：");
????????????for?(Object?obj:coursesToSelect){
????????????????Course?cr=(Course)obj;
????????????????System.out.println("課程："+cr.id+";"+cr.name);
????????????}
????????}


????public?static?void?main(String[]?args)?{
????????????SetTest?st=new?SetTest();
????????????st.testAdd();
????????????st.testForEach();
????????????Student?student=new?Student("1","小埋");
????????System.out.println("歡迎學生?"+student.name+"選課");
????????//創建一個scanner對象，用來接收從鍵盤輸入的課程ID
????????Scanner?console=new?Scanner(System.in);

????????for?(int?i=0;i<3;i++){
????????????System.out.println("輸入課程ID");
????????????String?courseId=console.next();
????????????for?(Course?cr:st.coursesToSelect){
????????????????if?(cr.id.equals(courseId)){
????????????????????student.courses.add(cr);
????????????????}
????????????}
????????}
????????st.testForEachForSet(student);
????}
????public?void?testForEachForSet(Student?student){
????????????//打印輸出?學生所選的課程
????????System.out.println("xuanle"?+student.courses.size()+"ke");
????????for?(Course?cr:student.courses){
????????????System.out.println("選擇了課程?"+cr.id+":"+cr.name);
????????}
????}
????}