Spring Ioc基础总结

1 Spring是一个解决企业应用的一个web容器，它的核心技术是IOC和AOP.

2 IoC 控制反转：

之前创建对象，需要手动去new，自己决定如何创建对象。在spring容器中，通过配置bean，来获取对象，让spring容器代替我们管理对象，这就是控制反转。

package com.sp.temp;

import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ApplicationContext sc=new ClassPathXmlApplicationContext("applicationContext.xml");
		UserDao ud=(UserDao) sc.getBean("userDao");
		System.out.println(ud.getAge()+":"+ud.getStr());
		List<String> list=ud.getList();
		for(String str:list){
			System.out.println("list:"+str);
		}
		Set<String> set=ud.getSet();
		for(String s:set){
			System.out.println("set:"+s);
		}
		Map map=ud.getMap();
		Set<String> keys=map.keySet();
		for(String s:keys){
			System.out.println(s+":"+(String)map.get(s));
		}
		
	}

}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="<a target=_blank href="http://www.springframework.org/schema/beans">http://www.springframework.org/schema/beans</a>"
  xmlns:xsi="<a target=_blank href="http://www.w3.org/2001/XMLSchema-instance">http://www.w3.org/2001/XMLSchema-instance</a>"
  xmlns:context="<a target=_blank href="http://www.springframework.org/schema/context">http://www.springframework.org/schema/context</a>"
  xmlns:tx="<a target=_blank href="http://www.springframework.org/schema/tx">http://www.springframework.org/schema/tx</a>"
  xmlns:aop="<a target=_blank href="http://www.springframework.org/schema/aop">http://www.springframework.org/schema/aop</a>"
  xsi:schemaLocation="<a target=_blank href="http://www.springframework.org/schema/beans">http://www.springframework.org/schema/beans</a> <a target=_blank href="http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">http://www.springframework.org/schema/beans/spring-beans-2.5.xsd</a>
        <a target=_blank href="http://www.springframework.org/schema/aop">http://www.springframework.org/schema/aop</a> <a target=_blank href="http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">http://www.springframework.org/schema/aop/spring-aop-2.5.xsd</a>">
 <bean name="userDao" class="com.sp.temp.UserDao">
  <property name="age" value="10"></property>
  <property name="str" value="test"></property>
  <property name="list">
   <list>
    <value>张三</value>
    <value>李四</value>
    <value>王五</value>
   </list>
  </property>
  <property name="set">
  <set>
   <value>张三</value>   
   <value>张三1</value>
  </set>   
  </property>
  <property name="map">
   <map>
    <entry>
     <key><value>zg</value></key>
     <value>中國</value>
    </entry>
    <entry>
     <key><value>mg</value></key>
     <value>美国</value>
    </entry>
   </map>
  </property>
 </bean>
 <bean name="userService" class="com.sp.temp.UserService">
  <property name="userDao" ref="userDao"></property>
 </bean>
</beans>

ApplicationContext继承于BeanFactory。

注入需要有属性声明和set方法。

3 用注解的方式完成注入：

（1） 在applicationContext.xml里的xsi:schemaLocation加入：

http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd
（2）被注入的属性值的set方法上加 @Autowired

<?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:tx="http://www.springframework.org/schema/tx"
		xmlns:aop="http://www.springframework.org/schema/aop"
		xsi:schemaLocation="http://www.springframework.org/schema/beans 
	 http://www.springframework.org/schema/beans/spring-beans-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/context         http://www.springframework.org/schema/context/spring-context-2.5.xsd"> 	<context:annotation-config/>
	<bean name="userDao" class="com.sp.temp.UserDao">
		<property name="age" value="10"></property>
		<property name="str" value="test"></property>
		<property name="list">
			<list>
				<value>张三</value>
				<value>李四</value>
				<value>王五</value>
			</list>
		</property>
		<property name="set">
		<set>
			<value>张三</value>			
			<value>张三1</value>
		</set>			
		</property>
		<property name="map">
			<map>
				<entry>
					<key><value>zg</value></key>
					<value>中國</value>
				</entry>
				<entry>
					<key><value>mg</value></key>
					<value>美国</value>
				</entry>
			</map>
		</property>
	</bean>
	<bean name="userService" class="com.sp.temp.UserService">
	
	</bean>
</beans>

在userService的bean中并没有配置属性userDao;

package com.sp.temp;

import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.beans.factory.annotation.Autowired;

public class UserService {
	private UserDao userDao;
	private String str;
	
	
	
	
	public UserDao getUserDao() {
		return userDao;
	}
	@Autowired
	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}
	public String getStr() {
		return str;
	}
	public void setStr(String str) {
		this.str = str;
	}
	
}

userDao的set方法上面加了注解 @Autowired完成该属性的注入；

使用注解的方式可以不用对要注入的属性进行引入，但是必须声明过这种属性的bean。

4 使用@resource注解进行注入：

@resouce注入资源，设置在要注入的属性set方法上，默认按名字查找，找不到再按类型，此时和@autowired相同。

@Autowired,按类型完成装载。

（1）在applicationContext.xml加入下面两句，声明使用注解和设置注解自动扫描的包。

<context:annotation-config/>

<context:component-scan base-package="com.sp.temp"></context:component-scan>

<?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:tx="http://www.springframework.org/schema/tx"
		xmlns:aop="http://www.springframework.org/schema/aop"
		xsi:schemaLocation="http://www.springframework.org/schema/beans 
	 http://www.springframework.org/schema/beans/spring-beans-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/context         http://www.springframework.org/schema/context/spring-context-2.5.xsd"> 	<context:annotation-config/>
	<context:component-scan base-package="com.sp.temp"></context:component-scan>
</beans>

（2）@Component(value="userDao") @Resource（name="userDao"） value和name要一致

package com.sp.temp;

import java.util.List;
import java.util.Map;
import java.util.Set;

import org.springframework.stereotype.Component;
@Component(value="userDao")
public class UserDao {
	private int age;
	
	private String str;
	private List list;
	private Set set;
	private Map map;
	
	public String getStr() {
		return str;
	}
	public void setStr(String str) {
		this.str = str;
	}
	public List getList() {
		return list;
	}
	public void setList(List list) {
		this.list = list;
	}
	public Set getSet() {
		return set;
	}
	public void setSet(Set set) {
		this.set = set;
	}
	public Map getMap() {
		return map;
	}
	public void setMap(Map map) {
		this.map = map;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	
	
}

package com.sp.temp;

import java.util.List;
import java.util.Map;
import java.util.Set;

import javax.annotation.Resource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service(value="userService")
public class UserService {
	private UserDao userDao;
	private String str;
	
	
	
	
	public UserDao getUserDao() {
		return userDao;
	}
	@Resource(name="userDao")
	public void setUserDao(UserDao userDao) {
		this.userDao = userDao;
	}
	public String getStr() {
		return str;
	}
	public void setStr(String str) {
		this.str = str;
	}
	
}

说明：spring常用的几个bean组件，@Component和@Repository,@service,@controller后面三个组件还没有扩展其他内容，和第一个组件作用一样。在spring容器启动的时候会加载配有这些组件的bean，相当于在xml里配置了bean.

@Resouce 注入资源，经常是注入上面的那几个组件资源。