二、java项目常用工具类之beancopy，bean和map转换工具类

项目环境：jdk1.8+spring4.3.12一、问题描述及试用场景：在项目规范中，要求类名以DO为尾的类作为数据库层实体bean，类名以MO为尾的类作为系统传输层实体bean，类名以VO为尾的类作为服务端与前端交互的实体bean。由于以上要求，需要在各个bean直接进行copy数据，除了傻瓜式的set/get or constructor来copy数据外，spring提供了直接copybean的工具类，原理其实就是通过java反射来根据目标bean的字段名调用其set方法来设值注入。除此之外，项目中还常见map与bean之间的转换。特封装此类，以供大家使用。二、样例代码：package org.egg.utils;import org.egg.enums.CommonErrorEnum;import org.egg.exception.CommonException;import org.springframework.beans.BeanUtils;import org.springframework.util.CollectionUtils;import java.beans.BeanInfo;import java.beans.IntrospectionException;import java.beans.Introspector;import java.beans.PropertyDescriptor;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.HashMap;import java.util.List;import java.util.Map;/*** @author dataochen* @Description bean工具类* @date: 2017/11/7 17:30*/public class BeanUtil {/*** 拷贝实体，source,target不允许为空** @param source* @param target*/public static void copyProperties(Object source, Object target) {BeanUtils.copyProperties(source, target);}/*** 拷贝实体集合，sourceList*只支持自定义实体集合拷贝*应用场景：DTO <=> DO 等*/

public static void copyPropertiesList(List sourceList, List targetList,Class clazz) throws InstantiationException,IllegalAccessException {
if (CollectionUtils.isEmpty(sourceList)) {
throw new CommonException(CommonErrorEnum.PARAM_ERROR);
}
for (Object items : sourceList) {
Object target = clazz.newInstance();
BeanUtils.copyProperties(items, target);
targetList.add(target);
}

}

/**
* Map --> Bean 2: 利用org.apache.commons.beanutils 工具类实现 Map --> Bean
*
* @param map
* @param obj
*/
public static void transMap2Bean2(Map<String, Object> map, Object obj) throws InvocationTargetException, IllegalAccessException {
if (map == null || obj == null) {
return;
}
org.apache.commons.beanutils.BeanUtils.populate(obj, map);
}

/**
* Map --> Bean 1: 利用Introspector,PropertyDescriptor实现 Map --> Bean
*
* @param map
* @param obj
*/
public static void transMap2Bean(Map<String, Object> map, Object obj) throws IntrospectionException, InvocationTargetException, IllegalAccessException {
BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();

for (PropertyDescriptor property : propertyDescriptors) {
String key = property.getName();
if (map.containsKey(key)) {
Object value = map.get(key);
// 得到property对应的setter方法
Method setter = property.getWriteMethod();
setter.invoke(obj, value);
}
}
}

/**
* Bean --> Map 1: 利用Introspector和PropertyDescriptor 将Bean --> Map
*
* @param obj
*/
public static Map<String, Object> transBean2Map(Object obj) throws IntrospectionException, InvocationTargetException, IllegalAccessException {

if (obj == null) {
return null;
}
Map<String, Object> map = new HashMap<String, Object>();
BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
for (PropertyDescriptor property : propertyDescriptors) {
String key = property.getName();

// 过滤class属性
if (!key.equals("class")) {
// 得到property对应的getter方法
Method getter = property.getReadMethod();
Object value = getter.invoke(obj);

map.put(key, value);
}

}
return map;
}

代码所用jar包maven坐标：<dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-core</artifactId>    <version>4.3.12.RELEASE</version></dependency><!-- https://mvnrepository.com/artifact/org.springframework/spring-beans --><dependency>    <groupId>org.springframework</groupId>    <artifactId>spring-beans</artifactId>    <version>4.3.12.RELEASE</version></dependency>项目地址：https://github.com/SuperEggMan/renting_frame_finish_bek; ps:感兴趣的可以start哦！声明：此项目仅是抛砖引玉，内容不是特别完善。如有转载，请注明此处。