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package com.xiaobu.entity;import lombok.Data;import java.io.Serializable;/** * @author xiaobu * @version JDK1.8.0_171 * @date on  2020/9/1 9:24 * @description */@Datapublic class Father implements Serializable {
       private static final long serialVersionUID = -3605840195099107460L;    private int age;    private String name;}

package com.xiaobu.entity;import lombok.Data;import java.io.Serializable;/** * @author xiaobu * @version JDK1.8.0_171 * @date on  2020/9/1 9:24 * @description */@Datapublic class Son  extends Father implements Serializable {
       private static final long serialVersionUID = -3605840195099107460L;    private String address;    public static void main(String[] args) {
           Son son1 = new Son();        son1.setAge(1);        son1.setName("laowang");        son1.setAddress("shenzhen");        Son son2 = new Son();        son2.setAge(2);        son2.setName("laoliu");        son2.setAddress("shenzhen");        System.out.println("son2 .equals(son1) " + son2 .equals(son1) );    }}

结果为true。

在Son类添加 @EqualsAndHashCode(callSuper = true) 默认为false。

可以看出没有@EqualsAndHashCode(callSuper = true)的Son类编译后的equals()方法

public boolean equals(final Object o) {
           if (o == this) {
               return true;        } else if (!(o instanceof Son)) {
               return false;        } else {
               Son other = (Son)o;            if (!other.canEqual(this)) {
                   return false;            } else {
                   Object this$address = this.getAddress();                Object other$address = other.getAddress();                if (this$address == null) {
                       if (other$address != null) {
                           return false;                    }                } else if (!this$address.equals(other$address)) {
                       return false;                }                return true;            }        }    }

有@EqualsAndHashCode(callSuper = true)的Son类编译后的equals()方法

public boolean equals(final Object o) {
           if (o == this) {
               return true;        } else if (!(o instanceof Son)) {
               return false;        } else {
               Son other = (Son)o;            if (!other.canEqual(this)) {
                   return false;            } else if (!super.equals(o)) {
                   return false;            } else {
                   Object this$address = this.getAddress();                Object other$address = other.getAddress();                if (this$address == null) {
                       if (other$address != null) {
                           return false;                    }                } else if (!this$address.equals(other$address)) {
                       return false;                }                return true;            }        }    }

可以看出来后者多了个

else if (!super.equals(o)) {
                             return false;                      }

拓展:

Data 注解生成的 toString 方法也只包含了子类自有属性。

参考:

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