1.功能说明: 顾名思义,Bean Utility就是Bean小工具,主要是封装了反射(reflection)和自省(introspection)的API(可以查看java.lang.reflect和java.beans文档),对bean进行操作。
主要功能: 操作Bean的属性,针对Bean属性排序,Bean和Map的转换,创建动态的Bean等
2.使用缺点,当两个不同的类A 类B有相同的字段名称,若类A的类型为 string,类B的类型为Integer,这里会报错。这种情况若要支持需要做特殊处理。
3. org.apache.commons.beanutils.PropertyUtils 利用反射操作bean的属性
getSimpleProperty()通过反射读取属性
1 | Person person=newPerson(); |
2 | person.setName=("heis"); |
3 | String name=(String)PropertyUtils.getSimpleProperty(person,"name");->heis |
getNestedProperty()检索嵌套的bean属性
3 | String authorName=(String)PropertyUtils.getNestedProperty(book,"author.name"); |
getIndexedProperty()访问数组或List型内Object的属性
1 | Chapter chapter1=newChapter(); |
2 | Chapter chapter2=newChapter(); |
3 | book.getChapters().add(chapter1); |
4 | book.getChapters().add(chapter2); |
5 | Chapter chapter=(Chapter)PropertyUtils.getIndexedProperty(book,"chapter[0]"); |
getMappedProperty()访问Map型bean属性的值
1 | Person person=newPerson(); |
2 | person.setName=("heis"); |
3 | Map favorites=newHashMap(); |
4 | favorites.put("food","rice"); |
5 | person.setFavorite(favorites); |
6 | String favorFood=(String)PropertyUtils.getMappedProperty(person,"favorites(food)");->rice |
getProperty()和setProperty()可以访问任何bean属性,通过表达式可以完成上面方法的功能
6 | |--Entry(key->"food",value->"") |
7 | PropertyUtils.setProperty(book,"authors[0].favorites(food)","rice"); |
8 | String favorFood=(String)PropertyUtils.getProperty(book,"authors[0].favorites(food)");->rice |
isReadable()和isWritable()检查bean是否可读(有getter)或可写(有setter)
1 | PropertyUtils.isReadable(book,"name"); |
2 | PropertyUtils.isWritable(book,"name"); |
getPropertyType()获取属性类型
1 | System.out.println(PropertyUtils.getPropertyType(person,"favorites"));->java.util.Map |
copyProperty()复制Bean属性,只复制引用,final类型和原始类型(primitive type)
2 | book1.setName("Commons Cookbook Notes"); |
4 | PropertyUtils.copyProperty(book2,book1); |
describe()创建包含Bean属性的Map
1 | Person person=newPerson(); |
4 | book.setName("Commons Cookbook Notes"); |
6 | Map propMap=PropertyUtils.describe(book); |
7 | propMap.get("name");->Commons Cookbook Notes |
8 | propMap.get("author");->person |