Spring中的工厂类、bean的作用范围和生命周期
1.Spring中的工厂类
1.1ApplicationContext
-
ClassPathXmlApplicationContext：加载类路径下 Spring 的配置文件
-
FileSystemXmlApplicationContext：加载本地磁盘下 Spring 的配置文件
1.1.1service
ApplicationContext：只要一读取配置文件，默认情况下就会创建对象。
package com.by.service;
import com.by.dao.UserDao;
import com.by.dao.UserDaoImpl;
public class UserServiceImpl implements UserService{
private UserDao userDao;
private String msg;
public UserServiceImpl() {
System.out.println("测UserServiceImpl对象创建了...");
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void setMsg(String msg) {
this.msg = msg;
}
public UserServiceImpl(UserDao userDao, String msg) {
this.userDao = userDao;
this.msg = msg;
}
@Override
public void adduser() {
System.out.println(userDao+"============"+msg);
userDao.adduser();
}
}
1.1.2applicationContext.xml
1.1.3测试
package com.by.web;
import com.by.dao.UserDao;
import com.by.service.UserService;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.ContextResource;
public class Client {
public static void main(String[] args) {
/**
* 测试BeanFactory和ApplicationContext的区别
*/
new ClassPathXmlApplicationContext("applicationContext.xml");
//XmlBeanFactory xbf = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));
// UserService userService = xbf.getBean("userService", UserService.class);
System.out.println("Spring IOC容器被创建了...............");
}
}
1.1.4结果
1.2BeanFactory
- spring中工厂的类结构图
BeanFactory：是在 getBean 的时候才会创建对象。
1.2.1service
package com.by.service;
import com.by.dao.UserDao;
import com.by.dao.UserDaoImpl;
public class UserServiceImpl implements UserService{
private UserDao userDao;
private String msg;
public UserServiceImpl() {
System.out.println("测UserServiceImpl对象创建了...");
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void setMsg(String msg) {
this.msg = msg;
}
public UserServiceImpl(UserDao userDao, String msg) {
this.userDao = userDao;
this.msg = msg;
}
@Override
public void adduser() {
System.out.println(userDao+"============"+msg);
userDao.adduser();
}
}
1.2.2applicationContext.xml
1.2.3测试
package com.by.web;
import com.by.dao.UserDao;
import com.by.service.UserService;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.ContextResource;
public class Client {
public static void main(String[] args) {
/**
* 测试BeanFactory和ApplicationContext的区别
*/
//new ClassPathXmlApplicationContext("applicationContext.xml");
XmlBeanFactory xbf = new XmlBeanFactory(new ClassPathResource("applicationContext.xml"));
UserService userService = xbf.getBean("userService", UserService.class);
System.out.println("Spring IOC容器被创建了...............");
}
}
1.2.4结果
1.3BeanFactroy和ApplicationContext区别
BeanFactroy：顶级接口，getBean时才创建对象
ApplicationContext：子接口，加载配置文件时就创建对象
2.bean的作用范围
2.1概述
-
在Spring中，bean作用域用于确定bean实例应该从哪种类型的Spring容器中返回给调用者。
2.2五种作用域
目前Spring Bean的作用域或者说范围主要有五种：
| 作用域 | 说明 |
|---|---|
| singleton | 默认值，Bean以单例方式存在spring IoC容器 |
| prototype | 每次从容器中调用Bean时都返回一个新的实例，相当于执行newInstance() |
| request | WEB 项目中，Spring 创建一个 Bean 的对象,将对象存入到 request 域中 |
| session | WEB 项目中，Spring 创建一个 Bean 的对象,将对象存入到 session 域中 |
| application | WEB 项目中，Spring 创建一个 Bean 的对象,将对象存入到 ServletContext 域中 |
可以通过 scope 属性控制bean的作用范围，其配置方式如下所示：
-
需要根据场景决定对象的单例、多例模式
单例：Service、DAO、SqlSessionFactory（或者是所有的工厂）
多例：Connection、SqlSession
2.3测试单例singleton
2.3.1service
package com.by.service;
import com.by.dao.UserDao;
import com.by.dao.UserDaoImpl;
public class UserServiceImpl implements UserService{
private UserDao userDao;
private String msg;
public UserServiceImpl() {
System.out.println("测UserServiceImpl对象创建了...");
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void setMsg(String msg) {
this.msg = msg;
}
public UserServiceImpl(UserDao userDao, String msg) {
this.userDao = userDao;
this.msg = msg;
}
@Override
public void adduser() {
System.out.println(userDao+"============"+msg);
userDao.adduser();
}
}
2.3.2applicationContext.xml
2.3.3测试
package com.by.web;
import com.by.dao.UserDao;
import com.by.service.UserService;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.ContextResource;
public class Client {
public static void main(String[] args) {
/**
* bean的五种作用范围
*/
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
for (int i = 0; i < 5; i++) {
UserService userService = context.getBean("userService", UserService.class);
System.out.println(userService);
}
}
}
2.3.4结果
2.4测试原型模式(多例)prototype
2.4.1service
package com.by.service;
import com.by.dao.UserDao;
import com.by.dao.UserDaoImpl;
public class UserServiceImpl implements UserService{
private UserDao userDao;
private String msg;
public UserServiceImpl() {
System.out.println("测UserServiceImpl对象创建了...");
}
public void setUserDao(UserDao userDao) {
this.userDao = userDao;
}
public void setMsg(String msg) {
this.msg = msg;
}
public UserServiceImpl(UserDao userDao, String msg) {
this.userDao = userDao;
this.msg = msg;
}
@Override
public void adduser() {
System.out.println(userDao+"============"+msg);
userDao.adduser();
}
}
2.4.2 applicationContext.xml
2.4.3测试
package com.by.web;
import com.by.dao.UserDao;
import com.by.service.UserService;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.ContextResource;
public class Client {
public static void main(String[] args) {
/**
* bean的五种作用范围
*/
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
for (int i = 0; i < 5; i++) {
UserService userService = context.getBean("userService", UserService.class);
System.out.println(userService);
}
}
}
2.4.4结果
3.bean的生命周期
3.1单例bean
3.1.1service
package com.by.service;
import com.by.dao.UserDao;
import com.by.dao.UserDaoImpl;
public class UserServiceImpl implements UserService{
private UserDao userDao;
private String msg;
public UserServiceImpl() {
System.out.println("测UserServiceImpl对象创建了...");
}
/**
*
*/
public void setUserDao(UserDao userDao) {
System.out.println("使用set注入....");
this.userDao = userDao;
}
public void init(){
System.out.println("初始化bean....");
}
public void destroy(){
System.out.println("销毁bean....");
}
@Override
public void adduser() {
System.out.println(userDao+"============"+msg);
userDao.adduser();
}
}
3.1.2applicationContext.xml
3.1.3测试
package com.by.web;
import com.by.dao.UserDao;
import com.by.service.UserService;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.ContextResource;
public class Client {
public static void main(String[] args) {
/**
* bean的生命周期
* 单例模式的周期：[容器启动时]--》set方法注入-->构造方法(实例化对象)--->init(初始化)---》[关闭容器]---》destory(销毁)
* 多例模式的周期：使用对象时---》set方法注入---》构造方法(实例化对象)---->init(初始化)----》jvm销毁对象，释放内存----》destroy(销毁)
*/
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
// 关闭容器
context.close();
// context.getBean("userService", UserService.class);
}
}3.1.4结果
3.2原型模式、多例bean
3.2.1service
package com.by.service;
import com.by.dao.UserDao;
import com.by.dao.UserDaoImpl;
public class UserServiceImpl implements UserService{
private UserDao userDao;
private String msg;
public UserServiceImpl() {
System.out.println("测UserServiceImpl对象创建了...");
}
/**
*
*/
public void setUserDao(UserDao userDao) {
System.out.println("使用set注入....");
this.userDao = userDao;
}
public void init(){
System.out.println("初始化bean....");
}
public void destroy(){
System.out.println("销毁bean....");
}
@Override
public void adduser() {
System.out.println(userDao+"============"+msg);
userDao.adduser();
}
}
3.2.2applicationContext.xml
3.2.3测试
package com.by.web;
import com.by.dao.UserDao;
import com.by.service.UserService;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.ContextResource;
public class Client {
public static void main(String[] args) {
/**
* bean的生命周期
* 单例模式的周期：[容器启动时]--》set方法注入-->构造方法(实例化对象)--->init(初始化)---》[关闭容器]---》destory(销毁)
* 多例模式的周期：使用对象时---》set方法注入---》构造方法(实例化对象)---->init(初始化)----》jvm销毁对象，释放内存----》destroy(销毁)
*/
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
// 关闭容器
// context.close();
context.getBean("userService", UserService.class);
}
}3.2.4结果
3.3总结
spring bean的生命周期
1、单例
[容器启动]---->构造方法(实例化)----->set方法(注入)----->init方法(初始化)---->[容器关闭]---->destroy方法(销毁)
2、多例
[使用对象]---->构造方法(实例化)----->set方法(注入)----->init方法(初始化)---->[jvm垃圾回收]--->destroy方法(销毁)