BeanUtils copyProperties to copy Arraylist

问题:

I know that BeanUtils can copy a single object to other.

Is it possible to copy an arraylist.

For example:

 FromBean fromBean = new FromBean("fromBean", "fromBeanAProp", "fromBeanBProp");
 ToBean toBean = new ToBean("toBean", "toBeanBProp", "toBeanCProp");
 BeanUtils.copyProperties(toBean, fromBean);

How to achieve this?

List<FromBean > fromBeanList = new ArrayList<FromBean >();  
List<ToBean > toBeanList = new ArrayList<ToBean >();  
BeanUtils.copyProperties(toBeanList , fromBeanList );

Its not working for me. Can any one please help me.

Thanks in advance.

回答1:

If you have two lists of equals size then you can do the following

for (int i = 0; i < fromBeanList.size(); i++) {
     BeanUtils.copyProperties(toBeanList.get(i), fromBeanList.get(i));
}

回答2:

If you have a list origin with data and list destination empty, the solution is:

    List<Object> listOrigin (with data)
    List<Object> listDestination= new ArrayList<Object>(); 

     for (Object source: listOrigin ) {
        Object target= new Object();
        BeanUtils.copyProperties(source , target);
        listDestination.add(target);
     }

回答3:

you can try something like this

for(int i=0; i<fromBeanList.size(); i++){
  BeanUtils.copyProperties(toBeanList.get(i) , fromBeanList.get(i) );
}

Hope this helps..

Oops it is already explained by someone now..

anyways try it.

回答4:

What you can do is to write your own generic copy class.

class CopyVector<S, T> {
    private Class<T> targetType;
    CopyVector(Class<T> targetType) {
        this.targetType = targetType;
    }
    Vector<T> copy(Vector<S> src) {
        Vector<T> target = new Vector<T>();
        for ( S s : src ) {
            T t = BeanUtils.instantiateClass(targetType);
            BeanUtils.copyProperties(s, t);
            target.add(t);
        }
        return target;
    }
}

A step further would also be to make the List type generic - this assumes you want to copy Vectors.

回答5:

BeanUtils.copyProperties, It only copy the property of same name. So, In case of ArrayList you can't do that.

According to docs:

Copy property values from the origin bean to the destination bean for all cases where the property names are the same.

回答6:

In spring BeanUtils.copyProperties, arguments are just opposite than apache commons lib

for(FromBean fromBean: fromBeanList) {
    if(fromBean != null) {
        ToBean toBean = new ToBean();
        org.springframework.beans.BeanUtils.copyProperties(fromBean, toBean);
        toBeanList.add(toBean);
    }
}