例如下述Java类:
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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; }
@Override public 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?
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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:
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@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 ; }
@Override public int hashCode() { return topology_pk.hashCode()+topology_id.hashCode(); } |
测试代码如下:
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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:
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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:
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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。
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原文链接:https://xiaoer.blog.csdn.net/article/details/85005295
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