java基础–(7)–一个标准的POJO，hashCode和equals方法的正确重写

版权声明：编码不易，禁止转载 https://blog.csdn.net/u_ascend/article/details/82152061

学生类

import org.apache.commons.lang3.builder.ReflectionToStringBuilder;

import java.util.Objects;

/**
 * Student
 *
 * @author ascend
 * @date 2018/5/25 14:42.
 */
public class Student {
    private Integer age;
    private String name;
    private Book book;

    public Student() {
        // default constructor
    }

    public Integer getAge() {
        return age;
    }

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

    public String getName() {
        return name;
    }

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

    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    @Override
    public int hashCode() {
        int result = 17;
        result = 31 * result + Objects.hashCode(age);
        result = 31 * result + Objects.hashCode(name);
        result = 31 * result + Objects.hashCode(book);
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Student)) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        Student student = (Student) obj;
        return Objects.equals(student.age, this.age) &&
                Objects.equals(student.name, this.name) &&
                Objects.equals(student.book, this.book);
    }

    @Override
    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }
}

书籍类

import org.apache.commons.lang3.builder.ReflectionToStringBuilder;

import java.util.Objects;

/**
 * Book
 *
 * @author ascend
 * @date 2018/5/25 14:42.
 */
public class Book {
    private String name;

    public Book() {
        // default constructor
    }

    public String getName() {
        return name;
    }

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

    @Override
    public int hashCode() {
        int result = 17;
        result = 31 * result + Objects.hashCode(name);
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (!(obj instanceof Book)) {
            return false;
        }
        if (obj == this) {
            return true;
        }
        Book book = (Book) obj;
        return Objects.equals(book.name, this.name);
    }

    @Override
    public String toString() {
        return ReflectionToStringBuilder.toString(this);
    }
}

看这里，看这里

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参考文章：https://segmentfault.com/q/1010000008435457?_ea=1648010