Spring实例化bean过程解析及完整代码示例

/** 
 * 实体类 
 */
public class Employee implements InitializingBean, DisposableBean, BeanNameAware {
	private String id;
	// 员工编号 
	private String name;
	// 员工姓名 
	private String sex;
	// 员工性别 
	private String age;
	// 员工年龄 
	private String nativePlace;
	// 员工籍贯 
	private String department;
	// 员工部门 
	private String beanName;
	// bean的名称 
	public Employee() {
		System.out.println("**********第一步：调用Bean的默认构造方法**********");
		this.id = "bean1:G080405214";
		System.out.println("bean1的 值：" + this);
		System.out.println("**********第二步：检查Bean配置文件中是否注入了Bean的属性值**********");
	}
	public void afterPropertiesSet() throws Exception {
		System.out.println("bean2的值：" + this);
		System.out.println("**********第三步：检查Bean是否实现了InitializingBean接口**********");
		this.name = "bean3:李晓红";
		this.sex = "bean3:女";
		this.age = "bean3:25";
		System.out.println("bean3的值：" + this);
	}
	public void init() {
		System.out 
		        .println("**********第四步：检查Bean配置文件中是否指定了init-method此属性**********");
		this.nativePlace = "bean3:北京";
		System.out.println("bean4的值：" + this);
	}
	public void destroy() throws Exception {
		System.out.println("**********服务停止**********");
	}
	public void setBeanName(String arg0) {
		System.out.println("**********设置bean的名称**********");
		this.beanName = "myBeanName";
	}
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	public String getAge() {
		return age;
	}
	public void setAge(String age) {
		this.age = age;
	}
	public String getNativePlace() {
		return nativePlace;
	}
	public void setNativePlace(String nativePlace) {
		this.nativePlace = nativePlace;
	}
	public String getDepartment() {
		return department;
	}
	public void setDepartment(String department) {
		this.department = department;
	}
	public String getBeanName() {
		return beanName;
	}
	@Override 
	  public String toString() {
		return "Employee [id=" + id + ", name=" + name + ", sex=" + sex 
		        + ", age=" + age + ", nativePlace=" + nativePlace 
		        + ", department=" + department + ", beanName=" + beanName + "]";
	}
}

/** 
 * Bean上下文工具类 
 */
public class BeanContextHelper {
	private static ApplicationContext _instance;
	static {
		if (_instance == null) 
		      _instance = buildApplicationContext();
	}
	private BeanContextHelper() {
	}
	/** 
   * 重新构建ApplicationContext对象 
   */
	public static ApplicationContext buildApplicationContext() {
		return new ClassPathXmlApplicationContext("applicationContext-base.xml");
	}
	/** 
   * 获取一个ApplicationContext对象 
   */
	public static ApplicationContext getApplicationContext() {
		return _instance;
	}
}

<?xml version="1.0" encoding="UTF-8"?> 
<beans xmlns="http://www.springframework.org/schema/beans" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" 
  xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" 
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd 
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd 
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd 
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"> 
 
  <!--==============测试Spring BeanFactory实例化Bean的过程--> 
  <bean id="employee" class="bean_factory_test.Employee" 
    init-method="init" destroy-method="destroy"> 
    <!--默认部门为研发部的--> 
    <property name="department"> 
      <value>bean2:研发部</value> 
    </property> 
  </bean> 
 
</beans>

/** 
 * BeanFactory实例化Bean工程测试类 
 */
public class Test {
	public static void main(String args[]) {
		Test test = new Test();
		test.test();
	}
	public void test() {
		ApplicationContext context = BeanContextHelper.getApplicationContext();
		Employee employee = (Employee) context.getBean("employee");
		System.out.println("**********从Spring BeanFactory获取到的最终bean实例**********");
		System.out.println("最终bean的值：" + employee);
	}
}

**********第一步：调用Bean的默认构造方法********** 
bean1的 值：Employee [id=bean1:G080405214, name=null, sex=null, age=null, nativePlace=null, department=null, beanName=null] 
**********第二步：检查Bean配置文件中是否注入了Bean的属性值********** 
**********设置bean的名称********** 
bean2的值：Employee [id=bean1:G080405214, name=null, sex=null, age=null, nativePlace=null, department=bean2:研发部, beanName=myBeanName] 
**********第三步：检查Bean是否实现了InitializingBean接口********** 
bean3的值：Employee [id=bean1:G080405214, name=bean3:李晓红, sex=bean3:女, age=bean3:25, nativePlace=null, department=bean2:研发部, beanName=myBeanName] 
**********第四步：检查Bean配置文件中是否指定了init-method此属性********** 
bean4的值：Employee [id=bean1:G080405214, name=bean3:李晓红, sex=bean3:女, age=bean3:25, nativePlace=bean3:北京, department=bean2:研发部, beanName=myBeanName] 
**********从Spring BeanFactory获取到的最终bean实例********** 
最终bean的值：Employee [id=bean1:G080405214, name=bean3:李晓红, sex=bean3:女, age=bean3:25, nativePlace=bean3:北京, department=bean2:研发部, beanName=myBeanName]