這是測(cè)試頁(yè)面

package uuu;

import java.util.Arrays;

import java.util.Iterator;

import java.util.List;

public class ListTest {

? ?private List courseToselect;

public List getCourseToselect() {

return courseToselect;

}

public void setCourseToselect(List courseToselect) {

this.courseToselect = courseToselect;

}

? ?public ListTest(){

? this.courseToselect = ArrayList();

? ?}

private List ArrayList() {

// TODO Auto-generated method stub

return null;

}

public void ?listAdd(){

Course cr1 = new Course("01 ", " ?JAVA");

courseToselect.add(cr1);

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

System.out.println("添加了課程： "+temp.getId()+temp.getName());

Course cr2 = new Course("02 ", " ?C語(yǔ)言");

courseToselect.add(0, cr2);

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

System.out.println("添加了課程： "+temp2.getId()+temp2.getName());

Course cr3 = new Course("03 ", " ?大學(xué)數(shù)學(xué)");

courseToselect.add( cr3);

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

System.out.println("添加了課程： "+temp3.getId()+temp3.getName());

Course cr4 = new Course("04 ", " ?大學(xué)英語(yǔ)");

courseToselect.add(2, cr2);

Course temp4 = (Course)courseToselect.get(2);

System.out.println("添加了課程： "+temp4.getId()+temp4.getName());

Course as[] = {new Course("5 ", " ?大學(xué)語(yǔ)文"),

new Course("6 ", " ?毛概")};

courseToselect.addAll(3,Arrays.asList(as));

Course temp5 = (Course) courseToselect.get(3);

Course temp6 = (Course) courseToselect.get(4);

System.out.println("添加了課程： "+temp5.getId()+temp5.getName()

? ? ? ? +temp6.getId()+temp6.getName());

}

? public void getcourse(){

?Iterator it ?= courseToselect.iterator();

?while (it.hasNext()) {

?Course course ?= (Course) it.next();

System.out.println("添加了如下課程:");

System.out.println(course.getId()+":"+course.getName());

}

? }

? ?public static void main(String[] args) {

ListTest ?lt = new ListTest();

lt.addtest();

}

}

在我所有的屬性封裝操作以后 ? 調(diào)用lt.addtest(); ?為什么會(huì)報(bào)錯(cuò)

出現(xiàn)提示 是 ?Add cast to'lt'

變成??((Object) lt).addtest();

請(qǐng)教大神 ?這一節(jié)封裝 ? 該怎么寫?

學(xué)生類封裝 ：

package uuu;

import java.util.HashSet;

import java.util.Set;

import asd.student;

public class Students {

? ?private String ?id;

? ?private String ?name;

? ?private Set ?courses;

? ?

? ?public Students (String id, String name){

? ?this.id = id;

? ?this.name = name;

? ?this.courses = new HashSet();

??

??

??

? ?}

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public Set getCourses() {

return courses;

}

public void setCourses(Set courses) {

this.courses = courses;

}

? ?

}

課程類封裝：

package uuu;

import java.util.List;

public class CourseList {

? ? private String ?id;

? ? private String name;

public String getId() {

return id;

}

public void setId(String id) {

this.id = id;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

? ? public CourseList(String id,String name){

? ? this.id = id;

? ? this.name = name;

? ? }

}

拜托諸位大神