Spring （三）注入依赖对象、注入集合类型的属性

1、 注入依赖对象
a. 基本类型对象注入：

<bean id="serviceDao" class="ServiceDaoBean" >
        <constructor-arg index="0" type="java.lang.String" /> // 构造器注入
        <property name="name" value="zhao" /> // 属性setter方法注入
    </bean>

b. 注入其他bean
方式1：

<bean id="serviceDao" class="ServiceDaoBean" ></bean>
    <bean id="service" class="ServiceBean" >
        <property name="serviceDao" ref="serviceDao" />
    </bean>

方式2：

<bean id="service" class="ServiceBean" >
        <property name="serviceDao" >
            <bean class="ServiceDaoBean" />
        </property>
    </bean>

c. 注入基本属性类型

<bean id="service" class="ServiceBean" >
        <property name="name" value="zhangsan" />
        <property name="id" value="88" />
    </bean>

原理如下:

 private void readXml(String filename) {
        SAXReader reader = new SAXReader();
        Document doc = null;
try {
            URL xmlPath = this.getClass().getClassLoader().getResource(filename); // 可以获取bin目录下的资源文件
            doc = reader.read(xmlPath);
            Map<String, String> nsMap = new HashMap<String, String>();
// 加入命名空间
            nsMap.put("ns", "http://www.springframework.org/schema/beans");
// 创建beans/bean查询路径
            XPath xsub = document.createXPath("//ns:beans/ns:bean");
// 设置命名空间
            xsub.setNamespaceURIs(nsMap);
// 获取文档下所有的bean
            List<Element> beans = xsub.selectNodes(document);
for (Element element : beans) {
                String id = element.attributeValue("id");
                String clazz = element.attributeValue("class");
                BeanDefinition d = new BeanDefinition(id, clazz);
                XPath propertySub = element.createXPath("ns:property");
                propertySub.setNamespaceURIs(nsMap);
                List<Element> propertyBeans = propertySub.selectNodes(element);
for ( Element propE : propertyBeans ) {
                    String pName = propE.attributeValue("name");
                    String pRef = propE.attributeValue("ref");
                    String value = propE.attributeValue("value");
                    PropertyDefinition pd = new PropertyDefinition(pName, pRef, value);
                    bds.getProperties().add(pd);
                }

                bds.add(d);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
}


private void injuectObject() {
for ( BeanDefinition beanDefinition : beanDefinition ) {
            Object bean = sigletons.get(beanDefinition.getId());
if ( bean != null ) {
try {
                    PropertyDescriptor[] ps = Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();
for ( PropertyDefinition propertyDefinition : beanDefinition.getProperties() ) {
for ( PropertyDescriptor propertyDesc : ps ) {
if ( propertyDefinition.getName().equals(propertyDesc.getName())) {
// 获取属性的setter方法
                                Method setter = propertyDesc.getWriteMethod();
if ( setter != null ) {
                                    Object value = null;
if ( propertyDefinition.getRef() != null && !"".equals(propertyDefinition.getRef().trim()) {
value = sigletons.get(propertyDefinition.getRef());
                                    } else {
// 需要引入commons-beanutils-core.jar包
value = ConvertUtils.convert(propertyDefinition.getValue(), propertyDesc.getPropertyType());
                                    }

                                    setter.setAccessible(true); // 如果setter为private
                                    setter.invoke(bean, value); //把引用注入到属性
                                }
                            }
                        }
                    }
                } catch (Exception e ) {
// TODO
                }
            }
        }
    }

2、 注入集合类型的属性

public class PersonServiceBean {
    private Set<String> sets = new HashSet<String>();
    private List<String> lists = new ArrayList<String>();
    private Properties properties = new Properties();
    private Map<String, String> maps = new HashMap<String, String>();

    // set和get方法必须有
}

applicationContext.xml

<bean id="personService" class="PersonServiceBean">
<property name="sets">
<set>
<value>第一个</value>
<value>第二个</value>
<value>第三个</value>
</set>
</property>
<property name="lists">
<list>
<value>第一个</value>
<value>第二个</value>
<value>第三个</value>
</list>
</property>
<property name="properties">
<props>
<prop key="key1">value1</prop>
<prop key="key2">value2</prop>
<prop key="key3">value3</prop>
</props>
</property>
<property name="maps">
<map>
<entry key="key-1" value="value-1">第一个</entry>
<entry key="key-2" value="value-2">第一个</entry>
<entry key="key-3" value="value-3">第一个</entry>
</map>
</property>
</bean>