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14.判断List中课程是否存在

分类： Java

2015-02-19 15:00:07


  1. package com.imooc.collection;

  3. import java.util.ArrayList;
  4. import java.util.Arrays;
  5. import java.util.List;
  6. import java.util.Scanner;

  8. /**
  9.  * @author ECJTU IsayesHu
  10.  *
  11.  */
  12. public class SetTest {

  14.     public List<Course> coursesToSelect;

  16.     private Scanner console;

  18.     public SetTest() {
  19.         coursesToSelect = new ArrayList<Course>();
  20.         console = new Scanner(System.in);
  21.     }

  23.     /**
  24.      * @param args
  25.      */

  27.     public void testAdd() {
  28.         // 创建一个对象，并通过调用add方法，添加到备选课程List中
  29.         Course cr1 = new Course("1", "数据结构");
  30.         coursesToSelect.add(cr1);
  31.         Course temp = (Course) coursesToSelect.get(0);

  33.         Course cr2 = new Course("2", "C语言");
  34.         coursesToSelect.add(0, cr2);
  35.         Course temp2 = (Course) coursesToSelect.get(0);

  37.         Course[] course = { new Course("3", "离散数学"), new Course("4", "汇编语言") };
  38.         coursesToSelect.addAll(Arrays.asList(course));
  39.         Course temp3 = (Course) coursesToSelect.get(2);
  40.         Course temp4 = (Course) coursesToSelect.get(3);

  42.         Course[] course2 = { new Course("5", "高等数学"), new Course("6", "大学英语") };
  43.         coursesToSelect.addAll(2, Arrays.asList(course2));
  44.         Course temp5 = (Course) coursesToSelect.get(2);
  45.         Course temp6 = (Course) coursesToSelect.get(3);
  46.     }

  48.     public void testForEach() {
  49.         System.out.println("有如下课程可以选择（通过foreach访问）：");
  50.         for (Object obj : coursesToSelect) {
  51.             Course cr = (Course) obj;
  52.             System.out.println("课程：" + cr.id + ":" + cr.name);
  53.         }
  54.     }

  56.     /*
  57.      * 测试List的contains方法
  58.      */
  59.     public void testListContains() {
  60.         // 取得被选课序列的第0个元素
  61.         Course course = coursesToSelect.get(0);
  62.         // 打印输出coursesToSelected是否包含course对象
  63.         System.out.println("取得课程：" + course.name);
  64.         System.out.println("备选课程中是否包含课程：" + course.name + ", "
  65.                 + coursesToSelect.contains(course));
  66.         // 创建一个新的课程对象，ID和名称，与对象完全一样
  67.         Course course2 = new Course(course.id, course.name);
  68.         System.out.println("新创建课程：" + course2.name);
  69.         System.out.println("备选课程中是否包含课程：" + course2.name + ", "
  70.                 + coursesToSelect.contains(course2));
  71.     }

  73.     public static void main(String[] args) {
  74.         SetTest st = new SetTest();
  75.         st.testAdd();
  76.         /*
  77.          * st.testForEach(); // 创建一个学生对象 Student student = new Student("1",
  78.          * "小明"); System.out.println("欢迎学生：" + student.name + "选课!"); //
  79.          * 创建一个Scanner对象，用来接收从键盘输入的课程ID Scanner console = new
  80.          * Scanner(System.in); for (int i = 0; i < 3; i++) {
  81.          * System.out.println("请输入课程ID"); String courseId = console.next(); for
  82.          * (Course cr : st.coursesToSelect) { if (cr.id.equals(courseId)) {
  83.          * student.courses.add(cr); student.courses.add(cr); } } }
  84.          * st.testForEachSet(student);
  85.          */
  86.         st.testListContains();
  87.     }

  89.     public void testForEachSet(Student student) {
  90.         // 打印输出，学生所选的课程
  91.         System.out.println("共选了" + student.courses.size() + "门课程!");
  92.         for (Course cr : student.courses) {// 记得把Student.java中的Set改成泛型Course
  93.             System.out.println("选择了课程：" + cr.id + ":" + cr.name);
  94.         }
  95.     }
  96. }







  1. package com.imooc.collection;

  3. import java.util.ArrayList;
  4. import java.util.Arrays;
  5. import java.util.List;
  6. import java.util.Scanner;

  8. /**
  9.  * @author ECJTU IsayesHu
  10.  *
  11.  */
  12. public class SetTest {

  14.     public List<Course> coursesToSelect;

  16.     private Scanner console;

  18.     public SetTest() {
  19.         coursesToSelect = new ArrayList<Course>();
  20.         console = new Scanner(System.in);
  21.     }

  23.     /**
  24.      * @param args
  25.      */

  27.     public void testAdd() {
  28.         // 创建一个对象，并通过调用add方法，添加到备选课程List中
  29.         Course cr1 = new Course("1", "数据结构");
  30.         coursesToSelect.add(cr1);
  31.         Course temp = (Course) coursesToSelect.get(0);

  33.         Course cr2 = new Course("2", "C语言");
  34.         coursesToSelect.add(0, cr2);
  35.         Course temp2 = (Course) coursesToSelect.get(0);

  37.         Course[] course = { new Course("3", "离散数学"), new Course("4", "汇编语言") };
  38.         coursesToSelect.addAll(Arrays.asList(course));
  39.         Course temp3 = (Course) coursesToSelect.get(2);
  40.         Course temp4 = (Course) coursesToSelect.get(3);

  42.         Course[] course2 = { new Course("5", "高等数学"), new Course("6", "大学英语") };
  43.         coursesToSelect.addAll(2, Arrays.asList(course2));
  44.         Course temp5 = (Course) coursesToSelect.get(2);
  45.         Course temp6 = (Course) coursesToSelect.get(3);
  46.     }

  48.     public void testForEach() {
  49.         System.out.println("有如下课程可以选择（通过foreach访问）：");
  50.         for (Object obj : coursesToSelect) {
  51.             Course cr = (Course) obj;
  52.             System.out.println("课程：" + cr.id + ":" + cr.name);
  53.         }
  54.     }

  56.     /*
  57.      * 测试List的contains方法
  58.      */
  59.     public void testListContains() {
  60.         // 取得被选课序列的第0个元素
  61.         Course course = coursesToSelect.get(0);
  62.         // 打印输出coursesToSelected是否包含course对象
  63.         System.out.println("取得课程：" + course.name);
  64.         System.out.println("备选课程中是否包含课程：" + course.name + ", "
  65.                 + coursesToSelect.contains(course));

  67.         // 提示输入课程名称
  68.         System.out.println("请输入课程名称：");
  69.         String name = console.next();
  70.         // 创建一个新的课程对象，ID和名称，与对象完全一样
  71.         Course course2 = new Course();
  72.         course2.name = name;
  73.         System.out.println("新创建课程：" + course2.name);
  74.         System.out.println("备选课程中是否包含课程：" + course2.name + ", "
  75.                 + coursesToSelect.contains(course2));
  76.     }

  78.     public static void main(String[] args) {
  79.         SetTest st = new SetTest();
  80.         st.testAdd();
  81.         /*
  82.          * st.testForEach(); // 创建一个学生对象 Student student = new Student("1",
  83.          * "小明"); System.out.println("欢迎学生：" + student.name + "选课!"); //
  84.          * 创建一个Scanner对象，用来接收从键盘输入的课程ID Scanner console = new
  85.          * Scanner(System.in); for (int i = 0; i < 3; i++) {
  86.          * System.out.println("请输入课程ID"); String courseId = console.next(); for
  87.          * (Course cr : st.coursesToSelect) { if (cr.id.equals(courseId)) {
  88.          * student.courses.add(cr); student.courses.add(cr); } } }
  89.          * st.testForEachSet(student);
  90.          */
  91.         st.testListContains();
  92.     }

  94.     public void testForEachSet(Student student) {
  95.         // 打印输出，学生所选的课程
  96.         System.out.println("共选了" + student.courses.size() + "门课程!");
  97.         for (Course cr : student.courses) {// 记得把Student.java中的Set改成泛型Course
  98.             System.out.println("选择了课程：" + cr.id + ":" + cr.name);
  99.         }
  100.     }
  101. }


  1. package com.imooc.collection;

  3. /**
  4.  * 课程类
  5.  *
  6.  * @author
  7.  *
  8.  */
  9. public class Course {

  11.     public String id;
  12.     public String name;

  14.     public Course(String id, String name) {
  15.         this.id = id;
  16.         this.name = name;
  17.     }

  19.     public Course() {

  21.     }

  23.     /*
  24.      * 重写某个类的equals方法
  25.      */
  26.     @Override
  27.     public boolean equals(Object obj) {
  28.         if (this == obj) {
  29.             return true;
  30.         }
  31.         if (obj == null) {
  32.             return false;
  33.         }
  34.         if (!(obj instanceof Course)) {
  35.             return false;
  36.         }
  37.         Course course = (Course) obj;
  38.         if (this.name == null) {
  39.             if (course.name == null) {
  40.                 return true;
  41.             } else
  42.                 return false;
  43.         } else {
  44.             if (this.name.equals(course.name))
  45.                 return true;
  46.             else
  47.                 return false;
  48.         }
  49.     }
  50. }



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