本文共 7700 字,大约阅读时间需要 25 分钟。
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falseStudent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trueEmployee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.sortequals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ListpersonList。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 或Comparator 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-3000.51import java.text.DecimalFormat;import java.util.ArrayList;import java.util.Arrays;import java.util.Collections;import java.util.Comparator;import java.util.Scanner;public class Main { public static void main(String[] args) { Scanner se = new Scanner(System.in); ArrayList列表=new ArrayList (); while (true) { String s或e =se.next(); if(s或e.equals("s")) { 列表.add(new Student(se.next(),se.nextInt(),se.nextBoolean(),se.next(),se.next())); }else if(s或e.equals("e")) { 列表.add(new Employee(se.next(),se.nextInt(),se.nextBoolean(),se.nextDouble(),new Company(se.next()))); }else { break; } } Collections.sort(列表, new 排序类()); for(Person 一个人:列表) { if(一个人 instanceof Student) { System.out.println(((Student)一个人).toString()); }else { System.out.println(((Employee)一个人).toString()); } } String 输入exit或其他=se.next(); if(输入exit或其他.equals("exit")) { return; }else { ArrayList stuList=new ArrayList (); ArrayList empList=new ArrayList (); for(Person w:列表) { if(w instanceof Student) { if(!stuList.contains((Student)w)) { stuList.add((Student)w); } } if(w instanceof Employee) { if(!empList.contains((Employee)w)) { empList.add((Employee)w); } } } System.out.println("stuList"); for(Student a:stuList) { System.out.println(a.toString()); } System.out.println("empList"); for(Employee a:empList) { System.out.println(a.toString()); } } }}abstract class Person{ String name;int age; boolean gender; public Person(String name, int age, boolean gender) { super(); if(name.equals("null")) { this.name = null; }else { this.name = name; } this.age = age; this.gender = gender; } @Override public String toString() { return name + "-" + age + "-" + 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,clazz; public Student(String name, int age, boolean gender, String stuNo, String clazz) { super(name, age, gender); if(stuNo.equals("null")) { this.stuNo = null; }else { this.stuNo = stuNo; } if(clazz.equals("null")) { this.clazz = null; }else { this.clazz = clazz; } } @Override public String toString() { return "Student:" + super.toString()+"-"+ stuNo + "-" + clazz; } @Override public boolean equals(Object obj) { if (this == obj) return true; if (!super.equals(obj)) return false; 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(String name) { if(!name.equals("null")) { this.name = name; }else { this.name = null; } } @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, double salary, Company company) { 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 (this == obj) return true; if (!super.equals(obj)) return false; if (getClass() != obj.getClass()) return false; Employee other = (Employee) obj; String newpersalary = new DecimalFormat("#.#").format(other.salary); String newthissalary = new DecimalFormat("#.#").format(this.salary); if (company == null) { if (other.company != null) return false; } else if (!company.equals(other.company)) return false; if (!newpersalary.equals(newthissalary)) return false; return true; }}class 排序类 implements Comparator { @Override public int compare(Person o1, Person o2) { if(o1.name.compareTo(o2.name)>0) { return 1; }else if(o1.name.compareTo(o2.name)<0) { return -1; }else { if(o1.age>o2.age) { return 1; }else if(o1.age
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