spring笔记-AttributeAccessor（转载）

原文出处：https://www.jianshu.com/p/3b338dda2437

1. 接口定义

 

 

定义了对对象元数据访问的抽象接口

2. AttributeAccessorSupport

AttributeAccessorSupport是实现AttributeAccessor的抽象类,内部由LinkedHashMap实现

 

 

测试代码:

public class AttributeAccessorSupportTests {

    private static final String NAME = "foo";

    private static final String VALUE = "bar";

    private AttributeAccessor attributeAccessor = new SimpleAttributeAccessorSupport();

    @Test
    public void setAndGet() throws Exception {
        this.attributeAccessor.setAttribute(NAME, VALUE);
        assertEquals(VALUE, this.attributeAccessor.getAttribute(NAME));
    }

    @Test
    public void setAndHas() throws Exception {
        assertFalse(this.attributeAccessor.hasAttribute(NAME));
        this.attributeAccessor.setAttribute(NAME, VALUE);
        assertTrue(this.attributeAccessor.hasAttribute(NAME));
    }

    @Test
    public void remove() throws Exception {
        assertFalse(this.attributeAccessor.hasAttribute(NAME));
        this.attributeAccessor.setAttribute(NAME, VALUE);
        assertEquals(VALUE, this.attributeAccessor.removeAttribute(NAME));
        assertFalse(this.attributeAccessor.hasAttribute(NAME));
    }

    @Test
    public void attributeNames() throws Exception {
        this.attributeAccessor.setAttribute(NAME, VALUE);
        this.attributeAccessor.setAttribute("abc", "123");
        String[] attributeNames = this.attributeAccessor.attributeNames();
        Arrays.sort(attributeNames);
        assertTrue(Arrays.binarySearch(attributeNames, NAME) > -1);
        assertTrue(Arrays.binarySearch(attributeNames, "abc") > -1);
    }

    @SuppressWarnings("serial")
    private static class SimpleAttributeAccessorSupport extends AttributeAccessorSupport {
    }

}

3.BeanMetadataAttributeAccessor

 

 

BeanMetadataAttributeAccessor继承自AttributeAccessorSupport,
其重写了相关方法,对象BeanMetadataAttribute定义了key和value2个属性

 

 

 

 

4. PropertyValue

继承自BeanMetadataAttributeAccessor

 

 

PropertyValue具备Name和Value属性,继承了BeanMetadataAttributeAccessor,那么可以理解PropertyValue具备动态扩展属性的能力

 

 

5.MutablePropertyValues

对PropertyValue的容器管理

测试代码:

    @Test
    public void testValid() throws Exception {
        MutablePropertyValues pvs = new MutablePropertyValues();
        pvs.addPropertyValue(new PropertyValue("forname", "Tony"));
        pvs.addPropertyValue(new PropertyValue("surname", "Blair"));
        pvs.addPropertyValue(new PropertyValue("age", "50"));
    }

6. PropertyValue应用

bean的property是最常用的

  <bean id="company" class="core.di.innerBeans.CompanyInfo">
        <property name="cname" value="Google"/>
        <property name="clocation"  value="Mountain View, US"/>  
        <property name="cturnover" value="2000000"/>
  </bean> 

对应的BeanDefinition中的propertyValues属性

 

 

也可以以代码的形式手动添加PropertyValue来为对象动态设置属性

    @Test
    public void test1()
    {
        GenericBeanDefinition item=new GenericBeanDefinition();

        item.setBeanClass(TestBean.class);
        item.getPropertyValues().add("name","test");
        AnnotationConfigApplicationContext applicationContext=new AnnotationConfigApplicationContext();
        applicationContext.registerBeanDefinition("item",item);
        applicationContext.refresh();
        TestBean bean= (TestBean) applicationContext.getBean("item");
    }

参考:
http://blog.csdn.net/dfl_always/article/details/53610351
http://blog.csdn.net/u012665780/article/details/18364309

作者：兴浩
链接：https://www.jianshu.com/p/3b338dda2437
來源：简书
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