Lombok中关于@Data的使用解析

目录

• Lombok
• @Data注解

• 内部实现
• 问题总结
• 解决方法

• 证明
• 小结一下

@Data
public class TestA {
    String oldName;
}

public class TestA {
    String oldName;
    public TestA() {
    }
    public String getOldName() {
        return this.oldName;
    }
    public void setOldName(String oldName) {
        this.oldName = oldName;
    }
    public boolean equals(Object o) {
        // 判断是否是同一个对象
        if (o == this) {
            return true;
        }
        // 判断是否是同一个类
        else if (!(o instanceof TestA)) {
            return false;
        } else {
            TestA other = (TestA) o;
            if (!other.canEqual(this)) {
                return false;
            } else {
                // 比较类中的属性(注意这里，只比较了当前类中的属性)
                Object this$oldName = this.getOldName();
                Object other$oldName = other.getOldName();
                if (this$oldName == null) {
                    if (other$oldName != null) {
                        return false;
                    }
                } else if (!this$oldName.equals(other$oldName)) {
                    return false;
                }
                return true;
            }
        }
    }
    protected boolean canEqual(Object other) {
        return other instanceof TestA;
    }
    public int hashCode() {
        int PRIME = true;
        int result = 1;
        Object $oldName = this.getOldName();
        int result = result * 59   ($oldName == null ? 43 : $oldName.hashCode());
        return result;
    }
    public String toString() {
        return "TestA(oldName="   this.getOldName()   ")";
    }
}

@Data
public class TestB extends TestA {
    private String name;
    private int age;
}

public class TestB extends TestA {
    private String name;
    private int age;
    public TestB() {
    }
    public String getName() {
        return this.name;
    }
    public int getAge() {
        return this.age;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public boolean equals(Object o) {
        if (o == this) {
            return true;
        } else if (!(o instanceof TestB)) {
            return false;
        } else {
            TestB other = (TestB)o;
            if (!other.canEqual(this)) {
                return false;
            } else {
                // 注意这里，真的是只比较了当前类中的属性，并没有比较父类中的属性
                Object this$name = this.getName();
                Object other$name = other.getName();
                if (this$name == null) {
                    if (other$name == null) {
                        return this.getAge() == other.getAge();
                    }
                } else if (this$name.equals(other$name)) {
                    return this.getAge() == other.getAge();
                }
                return false;
            }
        }
    }
    protected boolean canEqual(Object other) {
        return other instanceof TestB;
    }
    public int hashCode() {
        int PRIME = true;
        int result = 1;
        Object $name = this.getName();
        int result = result * 59   ($name == null ? 43 : $name.hashCode());
        result = result * 59   this.getAge();
        return result;
    }
    public String toString() {
        return "TestB(name="   this.getName()   ", age="   this.getAge()   ")";
    }
}

    public static void main(String[] args) {
        TestB t1 = new TestB();
        TestB t2 = new TestB();
        t1.setOldName("123");
        t2.setOldName("12345");
        String name = "1";
        t1.name = name;
        t2.name = name;
        int age = 1;
        t1.age = age;
        t2.age = age;
        System.out.println(t1.equals(t2));
        System.out.println(t2.equals(t1));
        System.out.println(t1.hashCode());
        System.out.println(t2.hashCode());
        System.out.println(t1 == t2);
        System.out.println(Objects.equals(t1, t2));
    }