Apache Commons BeanUtils 使用教程

admin 10年前
     <p><span style="font-size:medium;"><strong><span style="font-size:small;"><span style="color:#ff0000;">功能说明:</span> 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。<br /> <span style="color:#ff0000;">主要功能:</span> 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<br />  <br /> </span></strong></span></p>    <h2><span style="font-size:medium;"><span style="font-size:small;"><strong>2.1 org.apache.commons.beanutils.PropertyUtils 利用反射操作bean的属性</strong> </span></span></h2>    <p><span style="font-size:medium;"><span style="font-size:small;"><strong>getSimpleProperty()通过反射读取属性</strong> </span></span></p>    <pre class="brush:java; toolbar: true; auto-links: false;">Person person=new Person(); person.setName=("heis"); String name=(String)PropertyUtils.getSimpleProperty(person,"name");->heis</pre>    <strong>getNestedProperty()检索嵌套的bean属性</strong>    <pre class="brush:java; toolbar: true; auto-links: false;">Book book=new Book(); book.setAuthor(person); String authorName=(String)PropertyUtils.getNestedProperty(book,"author.name");//得到person的name</pre>    <p><span style="font-size:medium;"><span style="font-size:small;"> <strong>getIndexedProperty()访问数组或List型内Object的属性</strong> </span></span></p>    <pre class="brush:java; toolbar: true; auto-links: false;">Chapter chapter1=new Chapter(); Chapter chapter2=new Chapter(); book.getChapters().add(chapter1); book.getChapters().add(chapter2); Chapter chapter=(Chapter)PropertyUtils.getIndexedProperty(book,"chapter[0]");</pre>    <span style="font-size:small;"><span style="font-size:medium;"> <strong>getMappedProperty()访问Map型bean属性的值<pre class="brush:java; toolbar: true; auto-links: false;">Person person=new Person(); person.setName=("heis"); Map favorites=new HashMap(); favorites.put("food","rice"); person.setFavorite(favorites); String favorFood=(String)PropertyUtils.getMappedProperty(person,"favorites(food)");->rice</pre><span style="font-size:medium;"><span style="font-size:small;"><strong>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</strong> <pre class="brush:java; toolbar: true; auto-links: false;">这是一个树型的Bean属性视图 Book book |--List authors       |--[0]->Person person                     |--Map favorites                              |--Entry(key->"food",value->"") PropertyUtils.setProperty(book,"authors[0].favorites(food)","rice"); String favorFood=(String)PropertyUtils.getProperty(book,"authors[0].favorites(food)");->rice</pre> <p><span style="font-size:medium;"><span style="font-size:small;"> <strong>isReadable()和isWritable()检查bean是否可读(有getter)或可写(有setter)</strong> </span></span></p> <pre class="brush:java; toolbar: true; auto-links: false;">PropertyUtils.isReadable(book,"name"); PropertyUtils.isWritable(book,"name");</pre>getPropertyType()获取属性类型 <pre class="brush:java; toolbar: true; auto-links: false;">System.out.println(PropertyUtils.getPropertyType(person,"favorites"));->java.util.Map</pre>copyProperty()复制Bean属性,只复制引用,final类型和原始类型(primitive type) <pre class="brush:java; toolbar: true; auto-links: false;">Book book1=new Book(); book1.setName("Commons Cookbook Notes"); Book book2=new Book(); PropertyUtils.copyProperty(book2,book1);//将book1的name属性copy到book2</pre>describe()创建包含Bean属性的Map <pre class="brush:java; toolbar: true; auto-links: false;">Person person=new Person(); person.setName("heis"); Book book=new Book(); book.setName("Commons Cookbook Notes"); book.setAuthor(person); Map propMap=PropertyUtils.describe(book); propMap.get("name");->Commons Cookbook Notes propMap.get("author");->person</pre></span></span></strong></span></span>