# 比較兩個bean的內容是否相同

package gov.nii.iim.common.util;

import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.sql.Timestamp;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;

public class ClassCompareUtil {
    /**
     * 比較兩個bean的屬性值，返回一個boolean,true則表示兩個bean的內容是有差異的
     * @param oldObject 比較對象1
     * @param newObject 比較對象2
     * @return 回傳boolean值
     */
    public static boolean compareObject(Object oldObject, Object newObject) {
        Map<String, Map<String,Object>> resultMap=compareFields(oldObject,newObject);
        
        if(resultMap.size()>0) {
            System.out.println("兩個bean不相等");
            return true;
        }else {
            System.out.println("兩個bean相等");
            return false;
        }
    }
    
    /**
     * 比較兩個bean的屬性值，返回一個map以有差異的屬性值當作key和value做為一個Map,分別存oldObject,newObject的屬性值
     * @param oldObject 比較對象1
     * @param newObject 比較對象2
     * @return 比較结果回傳map
     */
    @SuppressWarnings("rawtypes")
    public static Map<String, Map<String,Object>> compareFields(Object oldObject, Object newObject) {
        Map<String, Map<String, Object>> map = null;
        
        try{    
            /**
             * 同一個class才做比較
             */
            if (oldObject.getClass() == newObject.getClass()) {
                map = new HashMap<String, Map<String,Object>>();
                
                Class clazz = oldObject.getClass();
                //獲取object的所有屬性
                PropertyDescriptor[] pds = Introspector.getBeanInfo(clazz,Object.class).getPropertyDescriptors();
                
                for (PropertyDescriptor pd : pds) {
                    //獲取所有屬姓名稱
                    String name = pd.getName();
                    
                    //獲取所有屬姓名稱的get方法
                    Method readMethod = pd.getReadMethod();
                    
                    // 在oldObject上用get方法來獲得oldObject的屬性值
                    Object oldValue = readMethod.invoke(oldObject);
                    // 在newObject上用get方法來獲得newObject的屬性值
                    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());
                    }
                    
                    
                    //如果欄位名稱等於這些欄位就不比較
                    if(name.equals("createUserId") || name.equals("createDeptId") || name.equals("createTime") ||
                       name.equals("maintainUserId") || name.equals("maintainDeptId") || 
                       name.equals("maintainProgramId") || name.equals("maintainHost") || name.equals("lastUpdateTime")) {
                        continue;
                    }
                    
                    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)) {// 比較兩個值是否相等，如果不相等就放入Map
                        
                        if(name.equals("newExtendDate") || name.equals("extendMark")) {
                            System.out.println("newValue:"+newValue.toString());
                                if(newValue == null || newValue.toString().equals("")) {
                                    continue;
                                }
                        }
                        
                        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;
    }

}

###### tags: `Java`