package com.test.collection;/*** 课程类* @author Administrator**/
public class Course {public String id;public String name;public Course(String id, String name){this.id = id;this.name = name;}
}

package com.test.collection;import java.util.HashSet;
import java.util.Set;
/*** 学生类* @author Administrator**/
public class Student {public String id;public String name;public Set courses;//所选课程public Student(String id, String name) {this.id = id;this.name = name;this.courses = new HashSet();//实例化sourses（Set是接口，接口不能被直接实例化）
    }
}

package com.test.collection;import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;/*** 备选课程类* @author Administrator**/
public class ListTest {/*** 用于存放备选课程的List*/public List coursesToSelect;public ListTest() {this.coursesToSelect = new ArrayList();}/*** 用于向coursesToSelect中添加备选课程*/public void testAdd() {Course c1 = new Course("1", "数据结构");//创建课程对象的实例coursesToSelect.add(c1);//调用add方法，添加课程到备选课程List中Course temp = (Course) coursesToSelect.get(0);//对象存入集合都变成Object，忽略对象之前的类型，取出时需类型转换System.out.println("添加了课程：" + temp.id + ":" + temp.name);Course c2 = new Course("2", "C语言");coursesToSelect.add(0, c2);//List中重载的另一个add()方法，可指定元素所添加的位置Course temp2 = (Course) coursesToSelect.get(0);System.out.println("添加了课程：" + temp2.id + ":" + temp2.name);coursesToSelect.add(c1);//List中元素可以重复Course temp0 = (Course) coursesToSelect.get(2);System.out.println("添加了课程：" + temp0.id + ":" + temp0.name);//以下方法会抛出数组下标越界异常//Course c3 = new Course("3", "Java");//coursesToSelect.add(4, c3);
        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(3);Course temp4 = (Course) coursesToSelect.get(4);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", "计算机网络")};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);}public static void main(String[] args) {ListTest lt = new ListTest();lt.testAdd();}
}

package com.test.collection;import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;/*** 备选课程类* @author Administrator**/
public class ListTest {/*** 用于存放备选课程的List*/public List coursesToSelect;public ListTest() {this.coursesToSelect = new ArrayList();}/*** 取得List中的元素的方法*/public void testGet() {int size = coursesToSelect.size();System.out.println("有以下课程选择：");for (int i = 0; i < size; i++) {Course c = (Course) coursesToSelect.get(i);System.out.println("课程：" + c.id + ":" + c.name);}}/*** 通过迭代器访问集合元素*/public void testIterator() {Iterator it = coursesToSelect.iterator();System.out.println("有以下课程选择(通过迭代器访问)：");while (it.hasNext()) {Course c = (Course) it.next();System.out.println("课程：" + c.id + ":" + c.name);}}/*** 通过for each方法访问集合元素*/public void testForEach() {System.out.println("有以下课程选择(通过for each访问)：");for (Object obj : coursesToSelect) {Course c = (Course) obj;System.out.println("课程：" + c.id + ":" + c.name);}}public static void main(String[] args) {ListTest lt = new ListTest();lt.testGet();lt.testIterator();lt.testForEach();}
}

public class ListTest {public void testModify() {Course c = new Course("7", "毛概");coursesToSelect.set(4, c);}
}

public class ListTest {public void testDelete() {/*coursesToSelect.remove(4);*//*Course c = (Course) coursesToSelect.get(4);coursesToSelect.remove(c); */Course[] courses = {(Course) coursesToSelect.get(4), (Course) coursesToSelect.get(5)};coursesToSelect.removeAll(Arrays.asList(courses));System.out.println("删除了课程");}
}