7-2 jmu-Java-03面向对象-06-继承覆盖综合练习-Person、Student、Employee、Company (15分)
定义Person抽象类,Student类、Company类,Employee类。
Person类的属性:String name
, int age
, boolean gender
Person类的方法:
public Person(String name, int age, boolean gender);
public String toString(); //返回"name-age-gender"格式的字符串
public boolean equals(Object obj);//比较name、age、gender,都相同返回true,否则返回false
Student类继承自Person
,属性:String stuNo, String clazz
Student类的方法:
//建议使用super复用Person类的相关有参构造函数
public Student(String name, int age, boolean gender, String stuNo, String clazz);
public String toString(); //返回 “Student:person的toString-stuNo-clazz”格式的字符串
public boolean equals(Object obj);//首先调用父类的equals方法,如果返回true,则继续比较stuNo与clazz。
Company类属性:String name
Company类方法:
public Company(String name);
public String toString(); //直接返回name
public boolean equals(Object obj);//name相同返回true
Employee类继承自Person
,属性:Company company, double salary
Employee类方法:
//建议使用super复用Person类的相关有参构造函数
public Employee(String name, int age, boolean gender, double salary, Company company);
public String toString(); //返回"Employee:person的toString-company-salary"格式的字符串
public boolean equals(Object obj);//首先调用父类的equals方法,如果返回true。再比较company与salary。
//比较salary属性时,使用DecimalFormat df = new DecimalFormat("#.#");保留1位小数
编写equals方法重要说明:
- 对Employee的company属性的比较。要考虑传入为null的情况。如果company不为null且传入为null,返回false
- 对所有String字符类型比较时,也要考虑null情况。
提示
- 排序可使用Collections.sort
- equals方法要考虑周全
main方法说明
-
创建若干Student对象、Employee对象。
输入s
,然后依次输入name age gender stuNo clazz
创建Student对象。
输入e
,然后依次输入name age gender salary company
创建Employee对象。
然后将创建好的对象放入List<Person> personList
。输入其他字符,则结束创建。
创建说明:对于String类型,如果为null
则不创建对象,而赋值为null
。对于company属性,如果为null
则赋值为null
,否则创建相应的Company对象。 -
对personList中的元素实现先按照姓名升序排序,姓名相同再按照年龄升序排序。提示:可使用
Comparable<Person>
或Comparator<Person>
-
接受输入,如果输入为
exit
则return
退出程序,否则继续下面步骤。 -
将personList中的元素按照类型分别放到
stuList
与empList
。注意:不要将两个内容相同的对象放入列表(是否相同是根据equals返回结果进行判定)。 -
输出字符串
stuList
,然后输出stuList中的每个对象。 -
输出字符串
empList
,然后输出empList中的每个对象。
1-3为一个测试点 4-6为一个测试点
输入样例:
s zhang 23 false 001 net15
e wang 18 true 3000.51 IBM
s zhang 23 false 001 net15
e bo 25 true 5000.51 IBM
e bo 25 true 5000.52 IBM
e bo 18 true 5000.54 IBM
e tan 25 true 5000.56 IBM
e tan 25 true 5000.51 IBM
s wang 17 false 002 null
s wang 17 false 002 null
e hua 16 false 1000 null
s wang 17 false 002 net16
e hua 16 false 1000 null
e hua 18 false 1234 MicroSoft
!
continue
输出样例:
Employee:bo-18-true-IBM-5000.54
Employee:bo-25-true-IBM-5000.51
Employee:bo-25-true-IBM-5000.52
Employee:hua-16-false-null-1000.0
Employee:hua-16-false-null-1000.0
Employee:hua-18-false-MicroSoft-1234.0
Employee:tan-25-true-IBM-5000.56
Employee:tan-25-true-IBM-5000.51
Student:wang-17-false-002-null
Student:wang-17-false-002-null
Student:wang-17-false-002-net16
Employee:wang-18-true-IBM-3000.51
Student:zhang-23-false-001-net15
Student:zhang-23-false-001-net15
stuList
Student:wang-17-false-002-null
Student:wang-17-false-002-net16
Student:zhang-23-false-001-net15
empList
Employee:bo-18-true-IBM-5000.54
Employee:bo-25-true-IBM-5000.51
Employee:hua-16-false-null-1000.0
Employee:hua-18-false-MicroSoft-1234.0
Employee:tan-25-true-IBM-5000.56
Employee:tan-25-true-IBM-5000.51
Employee:wang-18-true-IBM-3000.51
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws InterruptedException {
Scanner sc=new Scanner(System.in);
List<Person> personList=new ArrayList<Person>();
String name;
int age;
boolean gender;
String stuNo;
String clazz;
String companyName;
Company company;
double salary;
//输入
while(true) {
String t=sc.next();
if(t.equals("s")) {
name=sc.next();
age=sc.nextInt();
gender=sc.nextBoolean();
stuNo=sc.next();
clazz=sc.next();
if(name==null||stuNo==null||clazz==null) {
continue;
}
personList.add(new Student(name, age, gender, stuNo, clazz));
}else if(t.equals("e")){
name=sc.next();
age=sc.nextInt();
gender=sc.nextBoolean();
salary=sc.nextDouble();
companyName=sc.next();
company=new Company(companyName);
if(name==null) {
continue;
}
//除了companyName可以为空,其他为空均不能创建对象(应该是这么理解吧)
if(companyName==null) {
companyName="null"; //为空的话要给他赋值为空(删了也能过 可能写了句废话 )
}
personList.add(new Employee(name, age, gender, company, salary));
}else{ //要是遇到感叹号就该结束输入啦(题目上好像没说)
break;
}
}
//排序(因为之前的类都建好了,Person类还是抽象类,所以比较器只能用Comparator了)
Collections.sort(personList, new Name_AgeComparator());
for(int i=0;i<personList.size();i++) {
System.out.println(personList.get(i).toString());
}
//只要不输入return和exit就要分组啦
String str=sc.next();
while(true) {
if(str.equals("return")||str.equals("exit")) {
break;
}else {
//分组
List<Person> stuList=new ArrayList<Person>();
List<Person> empList=new ArrayList<Person>();
//判断过程要根据equals 是自己定义的 所以比较工资那有坑,用contains是不行的 所以还是循环比较吧
boolean flag1=true;
boolean flag2=true;
for(int i=0;i<personList.size();i++) {
if(personList.get(i).toString().indexOf("Student")>=0) {
if(stuList.size()==0) {
stuList.add(personList.get(i));
}
for(int j=0;j<stuList.size();j++) {
if(personList.get(i).equals(stuList.get(j))){
flag1=false;
}
}
if(flag1) {
stuList.add(personList.get(i));
}
flag1=true;
}else {
if(empList.size()==0) {
empList.add(personList.get(i));
}
for(int j=0;j<empList.size();j++) {
if(personList.get(i).equals(empList.get(j))){
flag2=false;
}
}
if(flag2) {
empList.add(personList.get(i));
}
flag2=true;
}
}
System.out.println("stuList");
for(int i=0;i<stuList.size();i++) {
System.out.println(stuList.get(i).toString());
}
System.out.println("empList");
for(int i=0;i<empList.size();i++) {
System.out.println(empList.get(i).toString());
}
break;
}
}
}
//Comparator需要创建一个类,又因为想在main方法里直接调,所以就要用static修饰
static class Name_AgeComparator implements Comparator<Person>{ //不加这个泛型也可以,但以后要强制转换
@Override
public int compare(Person o1, Person o2) {
if(o1.name.compareTo(o2.name)==0) {
if(o1.age==o2.age) {
return 0;
}else if(o1.age<o2.age) {
return -1;
}else {
return 1;
}
}else {
//比较字符串的方法(放张图片吧)
return(o1.name.compareTo(o2.name));
}
}
}
}
abstract class Person{
String name;
int age;
boolean gender;
public Person(String name, int age, boolean gender) {
super();
this.name = name;
this.age = age;
this.gender = gender;
}
@Override
public String toString() {
return this.name+'-'+String.valueOf(this.age)+'-'+String.valueOf(this.gender);
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Person other = (Person) obj;
if (age != other.age)
return false;
if (gender != other.gender)
return false;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
}
class Student extends Person{
String stuNo;
String clazz;
public Student(String name, int age, boolean gender, String stuNo, String clazz) {
super(name,age,gender);
this.clazz=clazz;
this.stuNo=stuNo;
}
@Override
public String toString() {
return"Student:"+ super.toString()+'-'+this.stuNo+'-'+this.clazz;
}
@Override
public boolean equals(Object obj) {
if (!super.equals(obj))
return false;
if (this == obj)
return true;
if (getClass() != obj.getClass())
return false;
Student other = (Student) obj;
if (clazz == null) {
if (other.clazz != null)
return false;
} else if (!clazz.equals(other.clazz))
return false;
if (stuNo == null) {
if (other.stuNo != null)
return false;
} else if (!stuNo.equals(other.stuNo))
return false;
return true;
}
}
class Company{
String name;
public Company(){
}
public Company(String name) {
this.name = name;
}
@Override
public String toString() {
return name;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Company other = (Company) obj;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
}
class Employee extends Person{
Company company;
double salary;
public Employee(String name, int age, boolean gender, Company company, double salary) {
super(name, age, gender);
this.company = company;
this.salary = salary;
}
@Override
public String toString() {
return "Employee:"+ super.toString()+'-'+company+'-'+salary;
}
@Override
public boolean equals(Object obj) {
if (!super.equals(obj))
return false;
if (this == obj)
return true;
if (getClass() != obj.getClass())
return false;
Employee other = (Employee) obj;
if (company == null) {
if (other.company != null)
return false;
}
else if (!company.equals(other.company))
return false;
//坑在这啊,要用decimal比较,要学会decimal这种用法
DecimalFormat df = new DecimalFormat("#.#");
if (!df.format(salary) .equals( df.format(other.salary)))
return false;
return true;
}
}
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