紧凑的等于和哈希码 [英] Compact equals and hashcode

问题描述

我有一个具有4个属性的bean:

I have a bean with 4 attributes:

user
institutionId
groupId
postingDate

我使用Eclipse生成equals和hashcode，但是生成的代码不是很漂亮.有没有紧凑的方法可以做到这一点?假设我要等于&哈希码以使用所有属性或它们的子集.

I use Eclipse to generate equals and hashcode but the resulting code is not pretty. Is there a compact way to do the same? Assuming I want equals & hashcode to use all the attributes or a subset of them.

@Override
public int hashCode() {
    final int prime = 31;
    int result = 1;
    result = prime * result + ((groupId == null) ? 0 : groupId.hashCode());
    result = prime * result + ((institutionId == null) ? 0 : institutionId.hashCode());
    result = prime * result + ((postingDate == null) ? 0 : postingDate.hashCode());
    result = prime * result + ((user == null) ? 0 : user.hashCode());
    return result;
}

@Override
public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    ManGroupKey other = (ManGroupKey) obj;
    if (groupId == null) {
        if (other.groupId != null)
            return false;
    } else if (!groupId.equals(other.groupId))
        return false;
    if (institutionId == null) {
        if (other.institutionId != null)
            return false;
    } else if (!institutionId.equals(other.institutionId))
        return false;
    if (postingDate == null) {
        if (other.postingDate != null)
            return false;
    } else if (!postingDate.equals(other.postingDate))
        return false;
    if (user == null) {
        if (other.user != null)
            return false;
    } else if (!user.equals(other.user))
        return false;
    return true;
}

推荐答案

您可以使用Apache-common-langs(

Instead of using the eclipse generated code, you can use Apache-common-langs(http://commons.apache.org/proper/commons-lang/) class HashCodeBuilder and EqualsBuilder to do this:

public int hashCode() {
   return HashCodeBuilder.reflectionHashCode(this);
}


public boolean equals(Object obj) {
   return EqualsBuilder.reflectionEquals(this);
 }

这篇关于紧凑的等于和哈希码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！