轉(zhuǎn)載自?https://blog.csdn.net/u013905744/article/details/73167861

需求：

有一個(gè)Map對象

[java]?view plaincopy

Map<String,Object>?map?=?new?HashMap<>();??

map.put("name",?"bellychang");??

map.put("likes",?new?String[]{"football",?"basketball"});??

希望實(shí)現(xiàn)一個(gè)通用方法，將其轉(zhuǎn)換為如下的JavaBean

[java]?view plaincopy

public?class?SimpleBean?{??

??

????private?String?name;??

????private?String[]?likes;??

??

????public?SimpleBean()?{??

????}??

??

????public?SimpleBean(String?name,?String[]?likes){??

????????this.name?=?name;??

????????this.likes?=?likes;??

????}??

??

????public?String?getName()?{??

????????return?name;??

????}??

??

????public?void?setName(String?name)?{??

????????this.name?=?name;??

????}??

??

????public?String[]?getLikes()?{??

????????return?likes;??

????}??

??

????public?void?setLikes(String[]?likes)?{??

????????this.likes?=?likes;??

????}??

??

????@Override??

????public?String?toString()?{??

????????return?"SimpleBean{"?+??

????????????????"name='"?+?name?+?'\''?+??

????????????????",?likes="?+?Arrays.toString(likes)?+??

????????????????'}';??

????}??

}??

工具類

[java]?view plaincopy

public?static?<T>?T?convertMap(Class<T>?type,?Map?map)?throws?IntrospectionException,?IllegalAccessException,??

????????InstantiationException,?InvocationTargetException?{??

????BeanInfo?beanInfo?=?null;?//?獲取類屬性??

????T?obj?=?null;??

????beanInfo?=?Introspector.getBeanInfo(type);??

????//?創(chuàng)建?JavaBean?對象??

????obj?=?type.newInstance();??

??

????//?給?JavaBean?對象的屬性賦值??

??

????//?獲取屬性的描述器(PropertyDescriptor)??

????PropertyDescriptor[]?propertyDescriptors?=?beanInfo.getPropertyDescriptors();??

??

????//?通過這個(gè)屬性描述器就可以獲取某個(gè)屬性對應(yīng)的?getter/setter?方法,然后就可以通過反射機(jī)制來調(diào)用這些方法??

????for?(int?i?=?0;?i?<?propertyDescriptors.length;?i++)?{??

????????PropertyDescriptor?descriptor?=?propertyDescriptors[i];??

????????String?propertyName?=?descriptor.getName();??

????????if?(map.containsKey(propertyName))?{??

????????????//?下面一句可以?try?起來，這樣當(dāng)一個(gè)屬性賦值失敗的時(shí)候就不會(huì)影響其他屬性賦值。??

????????????Object?value?=?map.get(propertyName);??

??

????????????Object[]?args?=?new?Object[1];??

????????????//getPropertyType得到屬性類型??

????????????if?(descriptor.getPropertyType()?==?Long.class)?{??

????????????????args[0]?=?Long.parseLong(value.toString());??

????????????}?else?if?(descriptor.getPropertyType()?==?Integer.class)?{??

????????????????args[0]?=?Integer.valueOf(value.toString());??

????????????}?else?{??

????????????????args[0]?=?value;??

????????????}??

??

????????????//getWriteMethod()得到此屬性的set方法----Method對象,然后用invoke調(diào)用這個(gè)方法??

????????????descriptor.getWriteMethod().invoke(obj,?args);??

????????}??

????}??

????return?obj;??

}??

測試類

[java]?view plaincopy

@Test??

public?void?testConvertMap()?throws?Exception?{??

????//將一個(gè)Map對象轉(zhuǎn)換為JavaBean??

????Map<String,Object>?map?=?new?HashMap<>();??

????map.put("name",?"changliang");??

????map.put("likes",?new?String[]{"football",?"basketball"});??

????SimpleBean?simpleBean?=?BeanToMapUtil.convertMap(SimpleBean.class,?map);??

????System.out.println(simpleBean);??

}??

注意事項(xiàng)：

1. Map的key與JavaBean的key一致

2. JavaBean中要有空的構(gòu)造函數(shù)，以及get，set方法

參考：java 中的內(nèi)省機(jī)制

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