给属性赋值的四种方式

第一种  设置注入

<bean id="emp0" class="com.bean.Employee" >
    <!--第一种  -->
    <property name="name" value="李智恩"></property>
     <property name="age" value="24"></property>
    </bean>

 第二种 键值分开

<bean id="emp1" class="com.bean.Employee" >
    <property name="name" >
    <value>李智恩</value>
    </property>
     <property name="age">
     <value>24</value>
     </property>
    </bean>

 测试类

@Test
	public void creatSpring(){
		//需要通过一个类来加载spring的配置
		String resource = "Spring.xml";
		ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext(resource);
		//换了一种方式赋值相当于上面的set方法
		Employee emp=(Employee) ac.getBean("emp1");
		System.out.println(emp);
		
	}

 

第三种 构造器注入

<bean id="emp2" class="com.bean.Employee" >
   <constructor-arg name="name" value="李智恩"></constructor-arg>
   <constructor-arg name="age" value="25"></constructor-arg>
    </bean>

bean类

public Employee(String name, Integer age) {
		super();
		this.name = name;
		this.age = age;
	}
	public Employee() {
		
	}

第四种  数组下标

 <!--第四种  -->
    <bean id="emp3" class="com.bean.Employee" >
   <constructor-arg index="0" value="胡歌"></constructor-arg>
   <constructor-arg index="1" value="25"></constructor-arg>
    </bean>

测试类

@Test
	public void creatSpring2(){
		String resource = "Spring.xml";
		ClassPathXmlApplicationContext cs = new ClassPathXmlApplicationContext(resource);
		Object bean = cs.getBean("emp3");
		System.out.println(bean);
	}

注意：名字需要和配置文档名字一致。