BeanUtils工具類copyProperties方法缺點及解決

使用類為spring-beans:4.3.13release包中的 org.springframework.beans.BeanUtils

BeanUtils.copyProperties(Object source, Object target); 

該方法會將source中同名屬性的值賦值給target中的同名屬性。（前提是source中的改屬性類型屬於target中該屬性類型【即為相同類或其子類，否則目標屬性還是為原默認值】）

import com.alibaba.fastjson.JSON;
import lombok.Data;
import org.junit.Test;
import org.springframework.beans.BeanUtils;

import java.util.Arrays;
import java.util.List;

/**
 * @author
 * @date 2019/10/26
 */
public class BeanUtil {
    public static void main(String[] args) {
        Bean2 bean2 = new Bean2();
        bean2.setIntField(1);
        bean2.setStrField("str");
        bean2.setObjField("obj");
        bean2.setListIntegerField(Arrays.asList("1","2assdsdsf","3"));
        bean2.setObjField1("1");
        Bean1 bean1 = new Bean1();

        //屬性中有元素不滿足目標屬性時依舊賦值成功Bean1.listIntegerField），未對能強轉成功的屬性做賦值處理(Bean1.objField1)
        BeanUtils.copyProperties(bean2,bean1);

        System.out.println("bean2:\t"+bean2);
        System.out.println("bean1:\t"+bean1);
        System.out.println("bean1.getListIntegerField:\t"+bean1.getListIntegerField().get(0));//調用到具體異常元素再拋出異常

        System.out.println("--------------------分割線--------------------");

        Bean1 bean11 = new Bean1();
        bean11.setIntField(1);
        bean11.setStrField("str");
        bean11.setObjField("obj");
        bean11.setListIntegerField(Arrays.asList(1,2,3));
        bean11.setObjField1(1);
        Bean2 bean21 = new Bean2();

        //Bean2.objField1 類型大於Bean1.objField1類型，賦值成功
        BeanUtils.copyProperties(bean11,bean21);

        System.out.println("bean11:\t"+bean11);
        System.out.println("bean21:\t"+bean21);
        System.out.println("bean21.getListIntegerField:\t"+bean21.getListIntegerField());

　　　

/*

運行結果：

        bean2: BeanUtil.Bean2(intField=1, strField=str, objField=obj, objField1=1, listIntegerField=[1, 2assdsdsf, 3])
        bean1: BeanUtil.Bean1(intField=1, strField=str, objField=obj, objField1=null, listIntegerField=[1, 2assdsdsf, 3])
        bean1.getListIntegerField: 1
                --------------------分割線--------------------
        bean11:    BeanUtil.Bean1(intField=1, strField=str, objField=obj, objField1=1, listIntegerField=[1, 2, 3])
        bean21:    BeanUtil.Bean2(intField=1, strField=str, objField=obj, objField1=1, listIntegerField=[1, 2, 3])
        bean21.getListIntegerField:    [1, 2, 3]

*/

    }

    @Test
    public void optimizeCopyProperties(){
        Bean2 bean2 = new Bean2();
        bean2.setIntField(1);
        bean2.setStrField("str");
        bean2.setObjField("obj");
//        bean2.setListIntegerField(Arrays.asList("1assdsdsf","2","3"));
        bean2.setListIntegerField(Arrays.asList("1","2","3"));
        bean2.setObjField1("1");

        //借助json工具類，底層以字符串實現強轉。對能強轉成功的屬性做賦值並賦值成功，若同名屬性值強轉賦值失敗則拋出異常
        Bean1 bean1 = JSON.parseObject(JSON.toJSONBytes(bean2), Bean1.class);

        System.out.println("bean2:\t"+bean2);
        System.out.println("bean1:\t"+bean1);
        System.out.println("bean1.getListIntegerField:\t"+bean1.getListIntegerField());

/*　　運行結果：
        bean2: BeanUtil.Bean2(intField=1, strField=str, objField=obj, objField1=1, listIntegerField=[1, 2, 3])
        bean1: BeanUtil.Bean1(intField=1, strField=str, objField=obj, objField1=1, listIntegerField=[1, 2, 3])
        bean1.getListIntegerField: [1, 2, 3]
*/

} 

   @Data
    public static class Bean1{
        private int intField;
        private String strField;
        private Object objField;
        private Integer objField1;
        private List<Integer> listIntegerField;
    }
    @Data
    public static class Bean2{
        private int intField;
        private String strField;
        private Object objField;
        private Object objField1;
        private List<String> listIntegerField;
    }
}

 

總結：可用阿里的json轉換工具處理類似的屬性賦值。其強轉賦值對能用字符串強轉的類型賦值更智能，屬性元素的異常賦值檢查也更嚴格。