点击关注公众号，实用技术文章及时了解

来源：xiaoer.blog.csdn.net/article/details/85005295

例如下述Java类：

import java.io.Serializable;
import java.util.List;public class Bean_Topology implements Serializable {private static final long serialVersionUID = 1L;public static long getSerialversionuid() {return serialVersionUID;}private Long topology_pk;private String topology_id;public String getTopology_id() {return topology_id;}public void setTopology_id(String topology_id) {this.topology_id = topology_id;}public Long getTopology_pk() {return topology_pk;}public void setTopology_pk(Long topology_pk) {this.topology_pk = topology_pk;}@Overridepublic String toString() {return "当前拓扑的PK为：" + topology_pk + "，ID为：" + topology_id;}
}

如下想判断下面两个对象中全部属性值是否一致时，有哪些办法呢？

Bean_Topology topology1 = new Bean_Topology();topology1.setTopology_id("1");Bean_Topology topology2 = new Bean_Topology();topology2.setTopology_pk(1L);topology2.setTopology_id("1");

方法一：重写Bean_Topology的equals方法和hashcode方法，代码如下：

@Override
public boolean equals(Object obj) {if (this == obj) {return true;}if (obj == null || getClass() != obj.getClass()) {return false;}Bean_Topology topology = (Bean_Topology) obj;if (topology_pk == null) {if (topology.topology_pk != null) {return false;} }else if (!topology_pk.equals(topology.topology_pk)) {return false; }if (topology_id == null) {if (topology.topology_id != null) {return false;} }else if (!topology_id.equals(topology.topology_id)) {return false; }return true;}@Overridepublic int hashCode() {return  topology_pk.hashCode()+topology_id.hashCode();}

测试代码如下：

if(topology1.equals(topology2)) {System.out.println("对象1与对象2的属性值无差异。");
}else {System.out.println("对象1与对象2的属性值有差异。");
}

输出结果为：

对象1与对象2的属性值有差异。

方法二：调用文章末尾的工具类，代码如下：

Map<String, Map<String,Object>> resultMap=compareFields(topology1,topology2);
int size=resultMap.size();
if(size>0) {System.out.println("对象1与对象2的属性值有差异,差异结果如下：");Iterator<String> it = resultMap.keySet().iterator();while(it.hasNext()) {String key=it.next();System.out.println("  "+key+"(oldValue:"+resultMap.get(key).get("oldValue")+",newValue:"+resultMap.get(key).get("newValue")+")");}
}else {System.out.println("对象1与对象2的属性值无差异！");
}

输出结果为：

对象1与对象2的属性值有差异,差异结果如下：topology_pk(oldValue:null,newValue:1)

工具类如下：

package com.sitech.modual.util.compare;import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;import com.sitech.modual.bean.Bean_Link;
import com.sitech.modual.bean.Bean_Topology;public class ClassCompareUtil {/*** 比较两个实体属性值，返回一个boolean,true则表时两个对象中的属性值无差异* @param oldObject 进行属性比较的对象1* @param newObject 进行属性比较的对象2* @return 属性差异比较结果boolean*/public static boolean compareObject(Object oldObject, Object newObject) {Map<String, Map<String,Object>> resultMap=compareFields(oldObject,newObject);if(resultMap.size()>0) {return false;}else {return true;}}/*** 比较两个实体属性值，返回一个map以有差异的属性名为key，value为一个Map分别存oldObject,newObject此属性名的值* @param oldObject 进行属性比较的对象1* @param newObject 进行属性比较的对象2* @return 属性差异比较结果map*/@SuppressWarnings("rawtypes")public static Map<String, Map<String,Object>> compareFields(Object oldObject, Object newObject) {Map<String, Map<String, Object>> map = null;try{ /*** 只有两个对象都是同一类型的才有可比性*/if (oldObject.getClass() == newObject.getClass()) {map = new HashMap<String, Map<String,Object>>();Class clazz = oldObject.getClass();//获取object的所有属性PropertyDescriptor[] pds = Introspector.getBeanInfo(clazz,Object.class).getPropertyDescriptors();for (PropertyDescriptor pd : pds) {//遍历获取属性名String name = pd.getName();//获取属性的get方法Method readMethod = pd.getReadMethod();// 在oldObject上调用get方法等同于获得oldObject的属性值Object oldValue = readMethod.invoke(oldObject);// 在newObject上调用get方法等同于获得newObject的属性值Object newValue = readMethod.invoke(newObject);if(oldValue instanceof List){continue;}if(newValue instanceof List){continue;}if(oldValue instanceof Timestamp){oldValue = new Date(((Timestamp) oldValue).getTime());}if(newValue instanceof Timestamp){newValue = new Date(((Timestamp) newValue).getTime());}if(oldValue == null && newValue == null){continue;}else if(oldValue == null && newValue != null){Map<String,Object> valueMap = new HashMap<String,Object>();valueMap.put("oldValue",oldValue);valueMap.put("newValue",newValue);map.put(name, valueMap);continue;}if (!oldValue.equals(newValue)) {// 比较这两个值是否相等,不等就可以放入map了Map<String,Object> valueMap = new HashMap<String,Object>();valueMap.put("oldValue",oldValue);valueMap.put("newValue",newValue);map.put(name, valueMap);}}}}catch(Exception e){e.printStackTrace();}return map;}}

注意： 本工具类不适用于比较包含List，Map等类的Class。

●【练手项目】基于SpringBoot的ERP系统，自带进销存+财务+生产功能

●分享一套基于SpringBoot和Vue的企业级中后台开源项目，代码很规范！

●能挣钱的，开源 SpringBoot 商城系统，功能超全，超漂亮！

PS：因为公众号平台更改了推送规则，如果不想错过内容，记得读完点一下“在看”，加个“星标”，这样每次新文章推送才会第一时间出现在你的订阅列表里。点“在看”支持我们吧！