201771010126.王燕《面向对象程序设计(Java)》第六周学习总结
实验六 继承定义与使用
实验时间 2018-9-28
1、实验目的与要求
(1) 理解继承的定义;
继承就是用已有类来构建新类的一种机制,当你继承了一个类时,就继承了这个类的方法和字段,同时你也可以在新类中添加新的方法和变量以适应新的情况。
继承的本质是代码复用。
(2) 掌握子类的定义要求
子类和超类是“is-a”关系。一般来说,子类比超类拥有的功能更加丰富。使用父类类型的引用指向子类的对象; 该引用只能调用父类中定义的方法和变量; 如果子类中重写了父类中的一个方法,那么在调用这个方法的时候,将会调用子类中的这个方法;(动态连接、动态调用) 变量不能被重写(覆盖),”重写“的概念只针对方法,如果在子类中”重写“了父类中的变量,那么在编译时会报错。
(3) 掌握多态性的概念及用法;
多态性:发送消息给某个对象,让该对象自行决定响应何种行为。 通过将子类对象引用赋值给超类对象引用变量来实现动态方法调用。 java 的这种机制遵循一个原则:当超类对象引用变量引用子类对象时,被引用对象的类型而不是引用变量的类型决定了调用谁的成员方法,但是这个被调用的方法必须是在超类中定义过的,也就是说被子类覆盖的方法。
(4) 掌握抽象类的定义及用途;如果自下而上仰视类的继承层次结构,位于上层的类更具通用性,甚至可能更加抽象。从某种角度看,祖先类更加通用,人们只将它作为派生其他类的基类,而不想作为使用的特定的实例类。为了提高程序的清晰度,包含一个或多个抽象方法的类本身必须被声明为抽象的。除了抽象方法之外,抽象类还可以包含具体数据和具体方法。 抽象方法充当着占位的角色,它们的具体实现在子类中。扩展抽象类可以有两种选择:一种是在子类中实现部分抽象方法,这样就必须将子类也标记为抽象类;另一种是实现全部抽象方法,这样子类就可以不是抽象的了。此外,类即使不含抽象方法,也可以将类声明为抽象类。 抽象类不能被实例化,即不能创建对象,只能产生子类。可以创建抽象类的对象变量,只是这个变量必须指向它的非抽象子类的对象。
(5) 掌握类中4个成员访问权限修饰符的用途
private--私有域或私有方法:只能在定义它的类中使用
public--公有域或公有方法:在任何其他的类中都可以访问
protected--受保护的域或方法:在所有子类和本包中可以访问
不用修饰符--友好域和友好方法:在同一包中的不同类之间访问
(7)掌握Object类的用途及常用API;
Object类是Java中所有类最终的祖先——每一个类都由它扩展而来。也就是说,在不给出超类的情况下,Java会自动把Object作为要定义类的超类。 可以使用类型为Object的变量指向任意类型的对象。但要对他们进行专门的操作,都要进行类型转换。
(8) 掌握ArrayList类的定义方法及用法;
ArrayList提供了三个构造器: public ArrayList(); 默认的构造器,将会以默认(16)的大小来初始化内部的数组
(9) 掌握枚举类定义方法及用途。
2、实验内容和步骤
实验1: 导入第5章示例程序,测试并进行代码注释。
测试程序1:
Ÿ 在elipse IDE中编辑、调试、运行程序5-1 (教材152页-153页) ;
Ÿ 掌握子类的定义及用法;
Ÿ 结合程序运行结果,理解并总结OO风格程序构造特点,理解Employee和Manager类的关系子类的用途,并在代码中添加注释。
1 package inheritance;
2
3 import java.time.*;
4
5 public class Employee
6 {
7 private String name;//定义成员变量
8 private double salary;
9 private LocalDate hireDay;
10
11 public Employee(String name, double salary, int year, int month, int day) //创建类对象的方法
12 {
13 this.name = name;
14 this.salary = salary;
15 hireDay = LocalDate.of(year, month, day);
16 }
17
18 public String getName()
19 {
20 return name;
21 }
22
23 public double getSalary()
24 {
25 return salary;
26 }
27
28 public LocalDate getHireDay()
29 {
30 return hireDay;
31 }
32
33 public void raiseSalary(double byPercent) // 创建计算薪资的方法
34 {
35 double raise = salary * byPercent / 100;
36 salary += raise;
37 }
38 } ![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929173838074-733315239.png)
1 package inheritance;
2
3 public class Manager extends Employee//Manager类继承Employee类{
5 private double bonus;
6
7 /**
8 * @param name the employee's name
9 * @param salary the salary
10 * @param year the hire year
11 * @param month the hire month
12 * @param day the hire day
13 */
14 public Manager(String name, double salary, int year, int month, int day)//定义Manager方法
15 {
16 super(name, salary, year, month, day);
17 bonus = 0;
18 }
19
20 public double getSalary()//添加计算工资的方法
21 {
22 double baseSalary = super.getSalary();
23 return baseSalary + bonus;
24 }
25
26 public void setBonus(double b)
27 {
28 bonus = b;
29 }
30 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929173950921-708149829.png)
1 package inheritance;
2
3 /**
4 * This program demonstrates inheritance.
5 * @version 1.21 2004-02-21
6 * @author Cay Horstmann
7 */
8 public class ManagerTest
9 {
10 public static void main(String[] args)
11 {
12 // 创建一个Manager对象
13 Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15)//引用数组创建Manager的信息
14 boss.setBonus(5000);
15
16 Employee[] staff = new Employee[3];
17
18 // 将经理和雇员都填充到数组中
19
20 staff[0] = boss;
21 staff[1] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
22 staff[2] = new Employee("Tommy Tester", 40000, 1990, 3, 15);
23
24 // 输出雇员对象的信息
25 for (Employee e : staff)
26 System.out.println("name=" + e.getName() + ",salary=" + e.getSalary());
27 }
28 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929174930416-1849101567.png)
测试程序2:
Ÿ 编辑、编译、调试运行教材PersonTest程序(教材163页-165页);
Ÿ 掌握超类的定义及其使用要求;
Ÿ 掌握利用超类扩展子类的要求;
Ÿ 在程序中相关代码处添加新知识的注释。
1 package abstractClasses;
2
3 /**
4 * This program demonstrates abstract classes.
5 * @version 1.01 2004-02-21
6 * @author Cay Horstmann
7 */
8 public class PersonTest
9 {
10 public static void main(String[] args)
11 {
12 Person[] people = new Person[2];
13
14 // 填充学生和雇员类对象数组中的信息
15 people[0] = new Employee("Harry Hacker", 50000, 1989, 10, 1);
16 people[1] = new Student("Maria Morris", "computer science");
17
18 // 输出学生的姓名
19 for (Person p : people)
20 System.out.println(p.getName() + ", " + p.getDescription());
21 }
22 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929175303213-2128877782.png)
1 package abstractClasses;
2
3 public class Student extends Person
4 {
5 private String major;
6
7 /**
8 * @param nama the student's name
9 * @param major the student's major
10 */
11 public Student(String name, String major)
12 {
13 // 创建一个超类
14 super(name);
15 this.major = major;
16 }
17
18 public String getDescription()
19 {
20 return "a student majoring in " + major;
21 }
22 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929175451406-251353069.png)
1 package abstractClasses;
2
3 import java.time.*;
4
5 public class Employee extends Person
6 {
7 private double salary;
8 private LocalDate hireDay;
9
10 public Employee(String name, double salary, int year, int month, int day)
11 {
12 super(name);
13 this.salary = salary;
14 hireDay = LocalDate.of(year, month, day);
15 }
16
17 public double getSalary()
18 {
19 return salary;
20 }
21
22 public LocalDate getHireDay()
23 {
24 return hireDay;
25 }
26
27 public String getDescription()//创建雇员类型的方法
28 {
29 return String.format("an employee with a salary of $%.2f", salary);
30 }
31
32 public void raiseSalary(double byPercent)
33 {
34 double raise = salary * byPercent / 100;
35 salary += raise;
36 }
37 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929175451406-251353069.png)
1 package abstractClasses;
2
3 public abstract class Person
4 {
5 public abstract String getDescription();
6 private String name;
7
8 public Person(String name)
9 {
10 this.name = name;
11 }
12
13 public String getName()
14 {
15 return name;
16 }
17 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929175451406-251353069.png)
测试程序3:
Ÿ 编辑、编译、调试运行教材程序5-8、5-9、5-10,结合程序运行结果理解程序(教材174页-177页);
Ÿ 掌握Object类的定义及用法;
Ÿ 在程序中相关代码处添加新知识的注释。
1 package arrayList;
2
3 import java.util.*;
4
5 /**
6 * This program demonstrates the ArrayList class.
7 * @version 1.11 2012-01-26
8 * @author Cay Horstmann
9 */
10 public class ArrayListTest
11 {
12 public static void main(String[] args)
13 {
14 // 填充雇员数组信息
15 ArrayList<Employee> staff = new ArrayList<>();
16
17 staff.add(new Employee("Carl Cracker", 75000, 1987, 12, 15));
18 staff.add(new Employee("Harry Hacker", 50000, 1989, 10, 1));
19 staff.add(new Employee("Tony Tester", 40000, 1990, 3, 15));
20
21 // 用以下方法为雇员涨5%的薪资
22 for (Employee e : staff)
23 e.raiseSalary(5);
24
25 // 输出所有雇员对象的信息
26 for (Employee e : staff)
27 System.out.println("name=" + e.getName() + ",salary=" + e.getSalary() + ",hireDay="
28 + e.getHireDay());
29 }
30 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929180540819-479328616.png)
1 package arrayList;
2
3 import java.time.*;
4
5 public class Employee
6 {
7 private String name;
8 private double salary;
9 private LocalDate hireDay;
10
11 public Employee(String name, double salary, int year, int month, int day)
12 {
13 this.name = name;
14 this.salary = salary;
15 hireDay = LocalDate.of(year, month, day);
16 }
17
18 public String getName()
19 {
20 return name;
21 }
22
23 public double getSalary()
24 {
25 return salary;
26 }
27
28 public LocalDate getHireDay()
29 {
30 return hireDay;
31 }
32
33 public void raiseSalary(double byPercent)
34 {
35 double raise = salary * byPercent / 100;
36 salary += raise;
37 }
38 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929180633650-1782470984.png)
测试程序4:
Ÿ 在elipse IDE中调试运行程序5-11(教材182页),结合程序运行结果理解程序;
Ÿ 掌握ArrayList类的定义及用法;
Ÿ 在程序中相关代码处添加新知识的注释。
1 package enums;
2
3 import java.util.*;
4
5 /**
6 * This program demonstrates enumerated types.
7 * @version 1.0 2004-05-24
8 * @author Cay Horstmann
9 */
10 public class EnumTest
11 {
12 public static void main(String[] args)
13 {
14 Scanner in = new Scanner(System.in);//创建一个输入尺寸的输入流
15 System.out.print("Enter a size: (SMALL, MEDIUM, LARGE, EXTRA_LARGE) ");
16 String input = in.next().toUpperCase();
17 Size size = Enum.valueOf(Size.class, input);
18 System.out.println("size=" + size);
19 System.out.println("abbreviation=" + size.getAbbreviation());
20 if (size == Size.EXTRA_LARGE)
21 System.out.println("Good job--you paid attention to the _.");
22 }
23 }
24
25 enum Size//声明一个尺寸的枚举类型
26 {
27 SMALL("S"), MEDIUM("M"), LARGE("L"), EXTRA_LARGE("XL");//列举具体尺寸
28
29 private Size(String abbreviation) { this.abbreviation = abbreviation; }
30 public String getAbbreviation() { return abbreviation; }
31
32 private String abbreviation;
33 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929180744291-1999720758.png)
测试程序5:
Ÿ 编辑、编译、调试运行程序5-12(教材189页),结合运行结果理解程序;
Ÿ 掌握枚举类的定义及用法;
Ÿ 在程序中相关代码处添加新知识的注释。
1 package equals;
2
3 import java.time.*;
4 import java.util.Objects;
5
6 public class Employee
7 {
8 private String name;
9 private double salary;
10 private LocalDate hireDay;
11
12 public Employee(String name, double salary, int year, int month, int day)
13 {
14 this.name = name;
15 this.salary = salary;
16 hireDay = LocalDate.of(year, month, day);
17 }
18
19 public String getName()
20 {
21 return name;
22 }
23
24 public double getSalary()
25 {
26 return salary;
27 }
28
29 public LocalDate getHireDay()
30 {
31 return hireDay;
32 }
33
34 public void raiseSalary(double byPercent)
35 {
36 double raise = salary * byPercent / 100;
37 salary += raise;
38 }
39
40 public boolean equals(Object otherObject)//进行相等测试
41 {
42 // 测试对象是否想等
43 if (this == otherObject) return true;
44
45 // 若不相等则返回错误,或返回空
46 if (otherObject == null) return false;
47
48 // 如果不是相同类型则不相等,返回错误信息
49 if (getClass() != otherObject.getClass()) return false;
50
51 // 确定other中的对象是雇员对象
52 Employee other = (Employee) otherObject;
53
54 // 测试是否在此域中
55 return Objects.equals(name, other.name) && salary == other.salary && Objects.equals(hireDay, other.hireDay);
56 }
57
58 public int hashCode()
59 {
60 return Objects.hash(name, salary, hireDay);
61 }
62
63 public String toString()
64 {
65 return getClass().getName() + "[name=" + name + ",salary=" + salary + ",hireDay=" + hireDay
66 + "]";
67 }
68 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929180906300-1879386932.png)
1 package equals;
2
3 /**
4 * This program demonstrates the equals method.
5 * @version 1.12 2012-01-26
6 * @author Cay Horstmann
7 */
8 public class EqualsTest
9 {
10 public static void main(String[] args)
11 { //添加各雇员对象的信息
12 Employee alice1 = new Employee("Alice Adams", 75000, 1987, 12, 15);
13 Employee alice2 = alice1;
14 Employee alice3 = new Employee("Alice Adams", 75000, 1987, 12, 15);
15 Employee bob = new Employee("Bob Brandson", 50000, 1989, 10, 1);
16 //返回雇员信息
17 System.out.println("alice1 == alice2: " + (alice1 == alice2));
18
19 System.out.println("alice1 == alice3: " + (alice1 == alice3));
20
21 System.out.println("alice1.equals(alice3): " + alice1.equals(alice3));
22
23 System.out.println("alice1.equals(bob): " + alice1.equals(bob));
24
25 System.out.println("bob.toString(): " + bob);
26 //添加Manager的信息
27 Manager carl = new Manager("Carl Cracker", 80000, 1987, 12, 15);
28 Manager boss = new Manager("Carl Cracker", 80000, 1987, 12, 15);
29 boss.setBonus(5000);
30 System.out.println("boss.toString(): " + boss);
31 System.out.println("carl.equals(boss): " + carl.equals(boss));
32 System.out.println("alice1.hashCode(): " + alice1.hashCode());
33 System.out.println("alice3.hashCode(): " + alice3.hashCode());
34 System.out.println("bob.hashCode(): " + bob.hashCode());
35 System.out.println("carl.hashCode(): " + carl.hashCode());
36 }
37 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929181018255-1064477733.png)
1 package equals;
2
3 public class Manager extends Employee//Manager类继承Employee类
4 {
5 private double bonus;
6
7 public Manager(String name, double salary, int year, int month, int day)
8 {
9 super(name, salary, year, month, day);
10 bonus = 0;
11 }
12
13 public double getSalary()
14 {
15 double baseSalary = super.getSalary();
16 return baseSalary + bonus;
17 }
18
19 public void setBonus(double bonus)
20 {
21 this.bonus = bonus;
22 }
23
24 public boolean equals(Object otherObject)
25 {
26 if (!super.equals(otherObject)) return false;
27 Manager other = (Manager) otherObject;
28 // 检查超类是否与此类相等
29 return bonus == other.bonus;
30 }
31
32 public int hashCode()
33 {
34 return java.util.Objects.hash(super.hashCode(), bonus);
35 }
36
37 public String toString()
38 {
39 return super.toString() + "[bonus=" + bonus + "]";
40 }
41 }
![](https://img2018.cnblogs.com/blog/1475124/201809/1475124-20180929181111415-833291870.png)
实验2:编程练习1
Ÿ 定义抽象类Shape:
属性:不可变常量double PI,值为3.14;
方法:public double getPerimeter();public double getArea())。
Ÿ 让Rectangle与Circle继承自Shape类。
Ÿ 编写double sumAllArea方法输出形状数组中的面积和和double sumAllPerimeter方法输出形状数组中的周长和。
Ÿ main方法中
1)输入整型值n,然后建立n个不同的形状。如果输入rect,则再输入长和宽。如果输入cir,则再输入半径。 2) 然后输出所有的形状的周长之和,面积之和。并将所有的形状信息以样例的格式输出。 3) 最后输出每个形状的类型与父类型,使用类似shape.getClass()(获得类型),shape.getClass().getSuperclass()(获得父类型);
思考sumAllArea和sumAllPerimeter方法放在哪个类中更合适?
输入样例:
3
rect
1 1
rect
2 2
cir
1
输出样例:
18.28
8.14
[Rectangle [width=1, length=1], Rectangle [width=2, length=2], Circle [radius=1]]
class Rectangle,class Shape
class Rectangle,class Shape
class Circle,class Shape
1 import java.util.Scanner;
2 public class calculate
3 {
4 public static void main(String[] args)
5 {
6 int r;
7 int x;
8 int y;
9 int i;
10 int a=100;
11 Scanner num;
12 num = new Scanner(System.in);
13 System.out.println("Input the num");
14 i = num.nextInt();
15 for(i=0;i<a;i++)
16 {
17 Scanner kind;
18 kind = new Scanner(System.in);
19 System.out.println("Input the shape");
20 String rect="rect";
21 String cir="cir";
22 String input=kind.next();
23 if(input.equals(rect))
24 {
25 Scanner sc;
26 sc = new Scanner(System.in);
27 System.out.println("Input the Rectangle length:");
28 x = sc.nextInt();
29 System.out.println("Input the Rectangle width:");
30 y = sc.nextInt();
31 System.out.println("Rectangle:"+"\n\n" +"\t"+"Perimeter:"+rectangle.getPerimeter(x,y)+"\n\n"+"\t"+"Area:"+rectangle.getArea(x,y)+"\n");
32 }
33 if(input.equals(cir))
34 {
35 Scanner sc;
36 sc = new Scanner(System.in);
37 System.out.println("Input the Circle radius:");
38 r = sc.nextInt();
39 System.out.println("Circlr:"+"\n\n"+"\t"+"Perimeter:"+circle.getPerimeter(r)+"\n\n"+"\t"+"Area"+circle.getArea(r)+"\n");
40 }
41 }
42 }
43 }
import java.util.Scanner;
public class calculate
{
public static void main(String[] args)
{
int r;
int x;
int y;
int i;
int a=100;
Scanner num;
num = new Scanner(System.in);
System.out.println("Input the num");
i = num.nextInt();
for(i=0;i<a;i++)
{
Scanner kind;
kind = new Scanner(System.in);
System.out.println("Input the shape");
String rect="rect";
String cir="cir";
String input=kind.next();
if(input.equals(rect))
{
Scanner sc;
sc = new Scanner(System.in);
System.out.println("Input the Rectangle length:");
x = sc.nextInt();
System.out.println("Input the Rectangle width:");
y = sc.nextInt();
System.out.println("Rectangle:"+"\n\n" +"\t"+"Perimeter:"+rectangle.getPerimeter(x,y)+"\n\n"+"\t"+"Area:"+rectangle.getArea(x,y)+"\n");
}
if(input.equals(cir))
{
Scanner sc;
sc = new Scanner(System.in);
System.out.println("Input the Circle radius:");
r = sc.nextInt();
System.out.println("Circlr:"+"\n\n"+"\t"+"Perimeter:"+circle.getPerimeter(r)+"\n\n"+"\t"+"Area"+circle.getArea(r)+"\n");
}
}
}
}
1 class rectangle extends shape
2 {//子类继承父类
3 public static double getArea(double width, double height)
4 {
5 return width*height;
6 }
7
8
9 public static double getPerimeter(double width, double height)
10 {
11 return 2*(width+height);
12 }
13 }
1 class circle extends shape
2 {//子类继承父类
3 public static double getArea(int radius)
4 {
5 return radius*radius*pi;
6 }
7
8
9 public static double getPerimeter(int radius)
10 {
11 return 2*pi*radius;
12 }
13 }
1 class shape
2 {//父类
3 private static String rect;
4 private static String cir;
5 public double width;//成员变量
6 public double length;
7 public double area;
8 public double Perimeter;
9 final static double pi=3.1415926;
10 final static String n=rect;
11 final static String m=cir;
12
13 public double getArea()
14 {//成员方法
15 return area;
16 }
17
18
19 public double getPerimeter()
20 {
21 return Perimeter;
22 }
23 }
实验3: 编程练习2
编制一个程序,将身份证号.txt 中的信息读入到内存中,输入一个身份证号或姓名,查询显示查询对象的姓名、身份证号、年龄、性别和出生地。
1 package check;
2 public class Student {
3
4 private String name;
5 private String number ;
6 private String sex ;
7 private String year;
8 private String province;
9
10 public String getName() {
11 return name;
12 }
13 public void setName(String name) {
14 this.name = name;
15 }
16 public String getnumber() {
17 return number;
18 }
19 public void setnumber(String number) {
20 this.number = number;
21 }
22 public String getsex() {
23 return sex ;
24 }
25 public void setsex(String sex ) {
26 this.sex =sex ;
27 }
28 public String getyaer() {
29 return year;
30 }
31 public void setyear(String year ) {
32 this.year=year ;
33 }
34 public String getprovince() {
35 return province;
36 }
37 public void setprovince(String province) {
38 this.province=province ;
39 }
40 }
1 package check;
2 import java.io.*;
3 import java.util.*;
4 public class Check{
5 private static ArrayList<Student> studentlist;
6 public static void main(String[] args)
7 {
8 studentlist = new ArrayList<>();
9 Scanner scanner = new Scanner(System.in);
10 File file = new File("C:\\下载\\身份证号.txt");
11 try
12 {
13 FileInputStream fis = new FileInputStream(file);
14 BufferedReader in = new BufferedReader(new InputStreamReader(fis));
15 String temp = null;
16 while ((temp = in.readLine()) != null)
17 {
18 Scanner linescanner = new Scanner(temp);
19 linescanner.useDelimiter(" ");
20 String name = linescanner.next();
21 String number = linescanner.next();
22 String sex = linescanner.next();
23 String year = linescanner.next();
24 String province =linescanner.nextLine();
25 Student student = new Student();
26 student.setName(name);
27 student.setnumber(number);
28 student.setsex(sex);
29 student.setyear(year);
30 student.setprovince(province);
31 studentlist.add(student);
32 }
33 }
34 catch (FileNotFoundException e)
35 {
36 System.out.println("学生信息文件找不到");
37 e.printStackTrace();
38 }
39 catch (IOException e)
40 {
41 System.out.println("学生信息文件读取错误");
42 e.printStackTrace();
43 }
44 boolean isTrue = true;
45 while (isTrue)
46 {
47 System.out.println("1.按姓名查询");
48 System.out.println("2.按身份证号查询");
49 System.out.println("3.退出");
50 int nextInt = scanner.nextInt();
51 switch (nextInt)
52 {
53 case 1:
54 System.out.println("请输入姓名");
55 String studentname = scanner.next();
56 int nameint = findStudentByname(studentname);
57 if (nameint != -1) {
58 System.out.println("查找信息为:身份证号:"
59 + studentlist.get(nameint).getnumber() + " 姓名:"
60 + studentlist.get(nameint).getName() +" 性别:"
61 +studentlist.get(nameint).getsex() +" 年龄:"
62 +studentlist.get(nameint).getyaer()+" 地址:"
63 +studentlist.get(nameint).getprovince()
64 );
65 }
66 else
67 {
68 System.out.println("不存在该学生");
69 }
70 break;
71 case 2:
72 System.out.println("请输入身份证号");
73 String studentid = scanner.next();
74 int idint = findStudentByid(studentid);
75 if (idint != -1)
76 {
77 System.out.println("查找信息为:身份证号:"
78 + studentlist.get(idint ).getnumber() + " 姓名:"
79 + studentlist.get(idint ).getName() +" 性别:"
80 +studentlist.get(idint ).getsex() +" 年龄:"
81 +studentlist.get(idint ).getyaer()+" 地址:"
82 +studentlist.get(idint ).getprovince()
83 );
84 }
85 else
86 {
87 System.out.println("不存在该学生");
88 }
89 break;
90 case 3:
91 isTrue = false;
92 System.out.println("程序已退出!");
93 break;
94 default:
95 System.out.println("输入有误");
96 }
97 }
98 }
99
100 public static int findStudentByname(String name)
101 {
102 int flag = -1;
103 int a[];
104 for (int i = 0; i < studentlist.size(); i++