Lombok @equalsandhashcode annotation how to make objects The equals () method compares only some attributes

Entity class

import lombok.Data;
import lombok.EqualsAndHashCode;


@Data
@EqualsAndHashCode
public class Cs {
    
    private int id;
    private String name;

    public Cs(int id, String name) {
    
        this.id = id;
        this.name = name;
    }
}

function

    public static void main(String[] args) {
    
        Cs cs1=new Cs(1," Little ");
        Cs cs2=new Cs(1," Little ");
        System.out.println(cs1.equals(cs2));
    }

View the generated class file

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package com.hieasy.rftools.common;

public class Cs {
    
    private int id;
    private String name;

    public Cs(int id, String name) {
    
        this.id = id;
        this.name = name;
    }

    public int getId() {
    
        return this.id;
    }

    public String getName() {
    
        return this.name;
    }

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

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

    public String toString() {
    
        return "Cs(id=" + this.getId() + ", name=" + this.getName() + ")";
    }

    public boolean equals(Object o) {
    
        if (o == this) {
    
            return true;
        } else if (!(o instanceof Cs)) {
    
            return false;
        } else {
    
            Cs other = (Cs)o;
            if (!other.canEqual(this)) {
    
                return false;
            } else if (this.getId() != other.getId()) {
    
                return false;
            } else {
    
                Object this$name = this.getName();
                Object other$name = other.getName();
                if (this$name == null) {
    
                    if (other$name != null) {
    
                        return false;
                    }
                } else if (!this$name.equals(other$name)) {
    
                    return false;
                }

                return true;
            }
        }
    }

    protected boolean canEqual(Object other) {
    
        return other instanceof Cs;
    }

    public int hashCode() {
    
        int PRIME = true;
        int result = 1;
        int result = result * 59 + this.getId();
        Object $name = this.getName();
        result = result * 59 + ($name == null ? 43 : $name.hashCode());
        return result;
    }
}

If we remove the annotation, it is the same , If you compare them all, you can not @EqualsAndHashCode annotation

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package com.hieasy.rftools.common;

public class Cs {
    
    private int id;
    private String name;

    public Cs(int id, String name) {
    
        this.id = id;
        this.name = name;
    }

    public int getId() {
    
        return this.id;
    }

    public String getName() {
    
        return this.name;
    }

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

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

    public boolean equals(Object o) {
    
        if (o == this) {
    
            return true;
        } else if (!(o instanceof Cs)) {
    
            return false;
        } else {
    
            Cs other = (Cs)o;
            if (!other.canEqual(this)) {
    
                return false;
            } else if (this.getId() != other.getId()) {
    
                return false;
            } else {
    
                Object this$name = this.getName();
                Object other$name = other.getName();
                if (this$name == null) {
    
                    if (other$name != null) {
    
                        return false;
                    }
                } else if (!this$name.equals(other$name)) {
    
                    return false;
                }

                return true;
            }
        }
    }

    protected boolean canEqual(Object other) {
    
        return other instanceof Cs;
    }

    public int hashCode() {
    
        int PRIME = true;
        int result = 1;
        int result = result * 59 + this.getId();
        Object $name = this.getName();
        result = result * 59 + ($name == null ? 43 : $name.hashCode());
        return result;
    }

    public String toString() {
    
        return "Cs(id=" + this.getId() + ", name=" + this.getName() + ")";
    }
}

But if we just want to compare name Attribute words , Class needs to be added @EqualsAndHashCode(onlyExplicitlyIncluded = true), If you want to compare only those attributes, add @EqualsAndHashCode.Include

import lombok.Data;
import lombok.EqualsAndHashCode;

/** * @author Zc * @date 2022 year 06 month 24 Japan  16:04 */
@Data
@EqualsAndHashCode(onlyExplicitlyIncluded = true)
public class Cs {
    
    private int id;
    @EqualsAndHashCode.Include
    private String name;

    public Cs(int id, String name) {
    
        this.id = id;
        this.name = name;
    }
}

result