⾯向对象和集合编程题

iiiiyu2026-05-18 12:33

代码过程：

复制代码 
package com.sy.homework;

import java.util.Objects;

public class Student {
    public String id = null; // 学号
    public String name; // 姓名
    public int age; // 年龄
    public double score; // 成绩

    public Student() {
    }

    public Student(String id, String name, int age, double score) {
        this.id = id;
        this.name = name;
        this.age = age;
        this.score = score;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Double getScore() {
        return score;
    }

    public void setScore(Double score) {
        this.score = score;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Student student = (Student) o;
        return age == student.age && Objects.equals(id, student.id) && Objects.equals(name, student.name) && Objects.equals(score, student.score);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id, name, age, score);
    }

    @Override
    public String toString() {
        return "Student{" +
                "id='" + id + '\'' +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", score='" + score + '\'' +
                '}';
    }
}
复制代码 
package com.sy.homework;

import java.util.ArrayList;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

public class Test {
    public static void main(String[] args) {
        List<Student> studentList = new ArrayList<>();
        studentList.add(new Student("S001", "张三", 20, 95.5));
        studentList.add(new Student("S002", "李四", 19, 88));
        studentList.add(new Student("S003", "王五", 21, 95.5));
        studentList.add(new Student("S002", "李四", 19, 88));

        Set<Student> set = new LinkedHashSet<>(studentList);
        List<Student> lists = new ArrayList<>(set);

        lists.sort((s1, s2) ->{
            int compare = Double.compare(s2.getScore(), s1.getScore());
            if(compare != 0){
                return compare;
            }
            return Integer.compare(s1.getAge(), s2.getAge());
        });
        System.out.println("===============去重+排序后学生列表==================");
        for (Student student : lists) {
            System.out.println(student);
        }
    }
}

代码过程：

复制代码 
package com.sy.homework2;

public class Employee extends  Person{
    private String number; //工号
    private String department; //部门
    private int salary; //薪资
    public Employee() {
    }
    public Employee(String name, int age, String number, String department, int salary) {
        super(name, age);
        this.number = number;
        this.department = department;
        this.salary = salary;
    }

    public String getNumber() {
        return number;
    }

    public void setNumber(String number) {
        this.number = number;
    }

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }

    public int getSalary() {
        return salary;
    }

    public void setSalary(int salary) {
        this.salary = salary;
    }

    @Override
    public String toString() {
        return "Employee{姓名='" + getName() + "', 部门='" + department + "', 薪资=" + salary + "}";
    }
}
复制代码 
package com.sy.homework2;

public class Person {
    private String name; // 姓名
    private int age; /// 年龄

    public Person() {
    }

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}
复制代码 
package com.sy.homework2;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

public class Test {
    public static void main(String[] args) {
        ArrayList<Employee> list = new ArrayList<>();
        list.add(new Employee("张三", 32 ,"1001","技术部",9500));
        list.add(new Employee("李四", 30 ,"1002","技术部",12000));
        list.add(new Employee("赵六", 31 ,"1003","市场部",7400));
        list.add(new Employee("王五", 29 ,"1004","行政部",8500));
        list.add(new Employee("小王", 28 ,"1005","市场部",7600));
        list.add(new Employee("小张", 27 ,"1006","行政部",8300));

        HashMap<String, List<Employee>> map = new HashMap<>();
        for (Employee e : list) {
            String dept = e.getDepartment();
            if (!map.containsKey(dept)){
                map.put(dept,new ArrayList<>());
            }
            map.get(dept).add(e);
        }

        System.out.println("=====部门薪资统计=====");
        for (String string : map.keySet()) {
            List<Employee> employees = map.get(string);
            double total = 0;
            for (Employee e : employees) {
                total += e.getSalary();
            }
            // 部门平均薪资
            double avg = total / employees.size();
            System.out.println("部门：" + string + "; 总薪资：" + total + "; 平均薪资：" + avg );
        }

        System.out.println("=====薪资大于8000的员工=====");
        ArrayList<Employee> arrayList = new ArrayList<>();
        for (Employee emp : list) {
            if (emp.getSalary() > 8000){
                arrayList.add(emp);
            }
        }
        //打印符合条件的员工
        for (Employee emp : arrayList) {
            System.out.println(emp);
        }

        System.out.println("=====技术部员工=====");
        List<Employee> employeeList = map.get("技术部");
        if (employeeList != null){
            for (Employee emp : employeeList) {
                System.out.println(emp);
            }
        }
    }
}

代码过程：

复制代码 
package com.sy.homework3;

import java.util.Objects;

public class Book {
    private String ISBN;
    private String name;// 书名
    private String author; // 作者
    private double price; // 价格

    public Book() {
    }

    public Book(String ISBN, String name, String author, double price) {
        this.ISBN = ISBN;
        this.name = name;
        this.author = author;
        this.price = price;
    }

    public String getISBN() {
        return ISBN;
    }

    public void setISBN(String ISBN) {
        this.ISBN = ISBN;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Book book = (Book) o;
        return Double.compare(price, book.price) == 0 && Objects.equals(ISBN, book.ISBN) && Objects.equals(name, book.name) && Objects.equals(author, book.author);
    }

    @Override
    public int hashCode() {
        return Objects.hash(ISBN, name, author, price);
    }

    @Override
    public String toString() {
        return "Book{ISBN='" + ISBN + "', 书名='" + name + "', 价格=" + price + "}";
    }
}
复制代码 
package com.sy.homework3;

import java.util.*;
import java.util.stream.Collectors;

public class Test {
    public static void main(String[] args) {
        List<Book> book1 = new ArrayList<>();
        book1.add(new Book("97801" , "Java编程思想" , "Rod" , 108));
        book1.add(new Book("97802" , "深入理解JVM" , "Rod" , 89));
        book1.add(new Book("97803" , "Spring实战" , "Rod" , 89));
        book1.add(new Book("97803" , "Spring实战" , "Rod" , 89));

        //去重
        Set<Book> book2 = new LinkedHashSet<>(book1);
        List<Book> list = new ArrayList<>(book2);

        //价格升序 书名字典序
        List<Book> sorted = list.stream()
                .sorted(new Comparator<Book>() {
                    @Override
                    public int compare(Book o1, Book o2) {
                        int compare = Double.compare(o1.getPrice(), o2.getPrice());
                        if (compare != 0) {
                            return compare;
                        }
                        return o1.getName().compareTo(o2.getName());
                    }
                })
                .collect(Collectors.toList());
        System.out.println("======图书列表========");
        for (Book book : sorted) {
            System.out.println(book);
        }
    }
}
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