第一種方式：方法注入
方法注入在Spring中是很少用的，主要應用是， 對象中可能定義了一個受保護的抽象方法，而容器可能在運行時實現他以返回由容器查詢得到的對象。
方法注入的最好用途之一就是處理單態、無狀態對象需要調用非單態、有狀態或者非線程安全對象的情況。
package com.mzsx.spring.notsingleton;
public interface IUserDao {
public void add();
public void delete();
public void load();package com.mzsx.spring.notsingleton;
public class UserDaoImp implements IUserDao {
@Override
public void add() {
System.out.println("dao添加用戶。。。。");
}
@Override
public void delete() {
System.out.println("dao***用戶。。。。");
}
@Override
public void load() {
System.out.println("dao加載用戶。。。。");
}
}package com.mzsx.spring.notsingleton;
public abstract class UserService {
protected abstract IUserDao getUserDao();
public void add() {
getUserDao().add();
}<?xml version="1.0" encoding="UTF-8"?> <beans xmlns=" http://www.springframework.org/schema/beans " xmlns:xsi=" http://www.w3.org/2001/XMLSchema-instance " xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd "> <bean id="userDao" class="com.mzsx.spring.notsingleton.UserDaoImp" scope="prototype"></bean> <bean id="userService" class="com.mzsx.spring.notsingleton.UserService" > <lookup-method name="getUserDao" bean="userDao" /> </bean>
package com.mzsx.spring.notsingleton;
import org.junit.Test;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestMain {
private BeanFactory factory= new ClassPathXmlApplicationContext("beans1.xml");
@Test
public void notSingleton(){
UserService users=(UserService)factory.getBean("userService");
System.out.println(users.getUserDao());
UserService users1=(UserService)factory.getBean("userService");
System.out.println(users1.getUserDao());
}
}結果：
2014-6-3 22:00:10 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons 信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@5bb966 : defining beans [userDao,userService]; root of factory hierarchy com.mzsx.spring.notsingleton.UserDaoImp@caf6c1 com.mzsx.spring.notsingleton.UserDaoImp@10e35d5
需要使用cgLib。
第二種方式：ApplicationContextAware
package com.mzsx.spring.notsingleton2;
public interface IUserDao {
public void add();
public void delete();
public void load();package com.mzsx.spring.notsingleton2;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
public class UserDaoImp implements IUserDao,ApplicationContextAware {
private ApplicationContext app;
@Override
public void add() {
System.out.println((IUserDao)app.getBean("userDao"));
System.out.println("dao添加用戶。。。。");
}
@Override
public void delete() {
System.out.println("dao***用戶。。。。");
}
@Override
public void load() {
System.out.println("dao加載用戶。。。。");
}
@Override
public void setApplicationContext(ApplicationContext app)
throws BeansException {
// TODO Auto-generated method stub
this.app=app;
}
}package com.mzsx.spring.notsingleton2;
public class UserService {
private IUserDao userDao;
public IUserDao getUserDao() {
return userDao;
}
public void setUserDao(IUserDao userDao) {
this.userDao = userDao;
}
public void add() {
userDao.add();
}<?xml version="1.0" encoding="UTF-8"?> <beans xmlns=" http://www.springframework.org/schema/beans " xmlns:xsi=" http://www.w3.org/2001/XMLSchema-instance " xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd "> <bean id="userDao" class="com.mzsx.spring.notsingleton2.UserDaoImp" scope="prototype"></bean> <bean id="userService" class="com.mzsx.spring.notsingleton2.UserService" > <property name="userDao" ref="userDao"></property> </bean>
package com.mzsx.spring.notsingleton2;
import org.junit.Test;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestMain {
private BeanFactory factory= new ClassPathXmlApplicationContext("beans2.xml");
@Test
public void notSingleton(){
UserService users=(UserService)factory.getBean("userService");
users.add();
UserService users1=(UserService)factory.getBean("userService");
users1.add();
}
}
結果：d
2014-6-3 22:03:20 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons 信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@1e903d5 : defining beans [userDao,userService]; root of factory hierarchy com.mzsx.spring.notsingleton2.UserDaoImp@1554d32 dao添加用戶。。。。 com.mzsx.spring.notsingleton2.UserDaoImp@13f136e dao添加用戶。。。。
ApplicationContextAware接口，此接口定義了一個方法setApplicationContext()方法，此方法在Spring初始化類以後，調用實現了ApplicationContextAware接口的類的setApplicationContext()方法，將自身的一個引用傳遞給此實例。
我們將這兩種單例調用非單例的例子對比一下，不難看出，第一種方式：方法注入要好於第二種方式：實現接口。原因是，第二種方式與Spring綁定了。而第一種方式則沒有這種情況，在Service中，我們根本看不出Spring的影子。