copy工具类--实现对象，对象内子对象，对象内集合等的复制

这里使用net.sf.dozer下的

DozerBeanMapper

实现对象,对象内子对象,以及对象内集合等的copy

需要引入net.sf.dozer的依赖  仓库链接net.sf.dozer:dozer:5.5.1

<dependency>
  <groupId>net.sf.dozer</groupId>
  <artifactId>dozer</artifactId>
  <version>5.5.1</version>
</dependency>

工具类实现主要有两个方法：一个是from方法，将原对象加载；一个是to方法，要copy到的对象；如果要对集合的copy，则用toList方法。

package xxx;

import org.dozer.DozerBeanMapper;
import org.dozer.Mapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

public class BeansCopy {
    private static Logger log = LoggerFactory.getLogger(BeansCopy.class);
    private static Mapper mapper = new DozerBeanMapper();
    private Object fromObj;
    private List<?> fromList;

    private BeansCopy() {
    }

    public static BeansCopy getInstance() {
        return new BeansCopy();
    }
    private static Mapper getMapperInstance() {
        return mapper;
    }

    public BeansCopy from(Object fromObj) {
        this.fromObj = fromObj;
        return this;
    }

    public BeansCopy from(List<?> fromList) {
        this.fromList = fromList;
        return this;
    }

    public <T> T to(Class<T> toClass) {
        return this.fromObj == null ? null : getMapperInstance().map(this.fromObj, toClass);
    }

    public <T> List<T> toList(Class<T> toClass) {
        if (this.fromList == null) {
            return null;
        } else {
            List<T> listTo = new ArrayList();
            Iterator var3 = this.fromList.iterator();

            while(var3.hasNext()) {
                Object myFromObj = var3.next();
                T toObj = getMapperInstance().map(myFromObj, toClass);
                listTo.add(toObj);
            }

            return listTo;
        }
    }

    public static void copy(Object from, Object to) {
        Method[] methods = from.getClass().getMethods();
        Map<String, Object> fromObj = new HashMap();
        Method[] var4 = methods;
        int var5 = methods.length;

        for(int var6 = 0; var6 < var5; ++var6) {
            Method method = var4[var6];
            String m = method.getName();
            if (m.startsWith("get")) {
                try {
                    Object result = method.invoke(from);
                    if (result != null) {
                        String field = m.substring(3).toLowerCase(Locale.getDefault());
                        fromObj.put(field, result);
                    }
                } catch (IllegalArgumentException | InvocationTargetException | IllegalAccessException var11) {
                    log.warn("{}", var11);
                }
            }
        }

        Set<String> fields = fromObj.keySet();
        Iterator var13 = fields.iterator();

        while(var13.hasNext()) {
            String str = (String)var13.next();
            invoke(to, str, fromObj.get(str));
        }

    }

    public static Object invoke(Object o, String field, Object value) {
        Method[] methods = o.getClass().getMethods();
        Method[] var4 = methods;
        int var5 = methods.length;

        for(int var6 = 0; var6 < var5; ++var6) {
            Method method = var4[var6];
            String m = method.getName();
            if (m.startsWith("set")) {
                String s = m.substring(3);
                if (s.equalsIgnoreCase(field)) {
                    try {
                        method.invoke(o, value);
                    } catch (IllegalArgumentException | InvocationTargetException | IllegalAccessException var11) {
                        log.warn("{}", var11);
                    }
                    break;
                }
            }
        }

        return o;
    }
}

调用方式：A是PO，AVo是VO，两个类属性一样。

//单个对象的复制
A a = new A();
AVo aVo = BeansCopy.getInstance().from(a).to(AVo.class);
log.info(JSON.toJSONString(aVo));

//集合的复制
List<A> As = Collections.singletonList(a);
List<AVo> AVoList = BeansCopy.getInstance().from(As).toList(AVo.class);
log.info(JSON.toJSONString(AVoList));

注意：日志是sl4j

很多东西更多的是写给自己的，下一次想用的时候能方便直接用。