下面為程序：package?com.imooc.collection; import?java.util.ArrayList; import?java.util.List; import?java.util.Arrays; /* ?*? ?*??備選課程類 ?*/ public?class?ListTest?{ public?List?coursesToSelect; /* *? *?用于存放備選課程的List */ public?ListTest(){ this.coursesToSelect?=?new?ArrayList(); } /* *? *?用于往?coursesToSelect?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); // 以下方法會拋出數組下標越界異常 // Course?cr3?=?new?Course("3","test"); // coursesToSelect.add(4,cr3); // 以下為出現錯誤，自己不會調試過來，"沒有Arrays類" Course[]?course?=?{new?Course("3","離散數學"),new?Course("4","匯編語言")}; coursesToSelect.addAll(Arrays.asList(course)); Course?temp3?=(Course)?coursesToSelect.get(2); Course?temp4?=(Course)?coursesToSelect.get(3); System.out.println("添加了兩門課程："+temp3.id+":"+ temp3.name+";"+temp4.id+":"+temp4.name); // 同上問題，百度說是引入包不正常，但是已經引入了ArrayList包。 Course[]?course2?=?{new?Course("5","高等數學"),new?Course("6","匯編語言")}; coursesToSelect.addAll(2,Arrays.asLst(course2)); 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); } public?void?testGet(){ int?size?=?coursesToSelect.size(); for(int?i=0;?i<size;i++){ Course?cr?=?(Course)?coursesToSelect.get(i); System.out.println("課程"+cr.id+":"+cr.name); } } public?static?void?main(?String[]?args){ ListTest?lt?=new?ListTest(); lt.testAdd(); lt.testGet(); } }