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Spring 装配bean

一、实例化方式：

三种实例化方式：默认构造，静态工厂，实例工厂

1、默认构造（前面的文章都是最基本的默认构造）

配置语法：

<bean id="" class="">

2、静态工厂

配置语法：

<bean id=""  class="工厂全限定类名"  factory-method="静态方法">

咱们来举个栗子：
代码：

public class MyBeanFactory {
	 // 创建实例
	public static UserService createService(){
		return new UserServiceImpl();
	}
}

配置：

	<!--class 确定静态工厂全限定类名
		factory-method 确定静态方法名-->
	<bean id="userServiceId" class="[包名].MyBeanFactory" factory-method="createService"></bean>

3、实例工厂

public class MyBeanFactory {
	public UserService createService(){
		return new UserServiceImpl();
	}
}

	<!-- 创建工厂实例 -->
	<bean id="myBeanFactoryId" class="com.itheima.c_inject.c_factory.MyBeanFactory"></bean>
	<!-- 获得userservice 
		* factory-bean 确定工厂实例
		* factory-method 确定普通方法
	-->
	<bean id="userServiceId" factory-bean="myBeanFactoryId" factory-method="createService"></bean>

二、作用域

配置信息：
<bean id="" class="" scope="">

<bean id="userServiceId" class="[包名].UserServiceImpl" 
		scope="prototype" ></bean>

如图所示为作用域类别与说明，Spring默认作用域为单例，常用的为单例（singleton）与多例（prototype）
bean作用域.png

三、生命周期

主要介绍初始化与销毁、后处理bean

1、初始化与销毁

目标方法执行前或后，将进行初始化或销毁。初始化方法常用于准备资源、初始化数据，销毁方法常用于释放资源等。
要求：1.容器必须close，销毁方法执行; 2.必须是单例的

public class UserServiceImpl implements UserService {

	@Override
	public void addUser() {
		System.out.println("e_lifecycle add user");
	}
	
	public void myInit(){
		System.out.println("初始化");
	}
	public void myDestroy(){
		System.out.println("销毁");
	}

}

	<bean id="userServiceId" class="com.itheima.e_lifecycle.UserServiceImpl" 
		init-method="myInit" destroy-method="myDestroy" ></bean>

2、BeanPostProcessor 后处理Bean

spring 提供一种机制，只要实现此接口BeanPostProcessor，并将实现类提供给spring容器，spring容器将自动执行，在初始化方法前执行before()，在初始化方法后执行after() 。配置

public class MyBeanPostProcessor implements BeanPostProcessor {
	@Override
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
		System.out.println("前方法 ： " + beanName);
		return bean;
	}
	@Override
	public Object postProcessAfterInitialization(final Object bean, String beanName) throws BeansException {
		System.out.println("后方法 ： " + beanName);
		// bean 目标对象,可生成 jdk 代理
		return Proxy.newProxyInstance(
					MyBeanPostProcessor.class.getClassLoader(), 
					bean.getClass().getInterfaces(), 
					new InvocationHandler(){
						@Override
						public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
							System.out.println("------开启事务");
							//执行目标方法
							Object obj = method.invoke(bean, args);
							System.out.println("------提交事务");
							return obj;
						}});
	}
}

配置添加：

<!-- 将后处理的实现类注册给spring -->
	<bean class="[包名].MyBeanPostProcessor"></bean>

四、属性依赖注入

依赖注入方式分为：手动装配和自动装配；

1、基于XML的手动装配：构造方法、setter方法；

1.1构造方法

目标类：

public class User {
	
	private Integer uid;
	private String username;
	private Integer age;
	
	public User(Integer uid, String username) {
		super();
		this.uid = uid;
		this.username = username;
	}
	
	public User(String username, Integer age) {
		super();
		this.username = username;
		this.age = age;
	}

	<!-- 构造方法注入 
		* <constructor-arg> 用于配置构造方法一个参数argument
			name ：参数的名称
			value：设置普通数据
			ref：引用数据，一般是另一个bean id值
			index ：参数的索引号，从0开始 。如果只有索引，匹配到了多个构造方法时，默认使用第一个。
			type ：确定参数类型
	-->
	<bean id="userId" class="com.itheima.f_xml.a_constructor.User" >
		<constructor-arg index="0" type="java.lang.String" value="1"></constructor-arg>
		<constructor-arg index="1" type="java.lang.Integer" value="2"></constructor-arg>
	</bean>

1.2setter方法

	<bean id="personId" class="com.itheima.f_xml.b_setter.Person">
		<property name="pname" value="阳志"></property>
		<property name="age">
			<value>1234</value>
		</property>
		
		<property name="homeAddr" ref="homeAddrId"></property>
		<property name="companyAddr">
			<ref bean="companyAddrId"/>
		</property>
	</bean>
	
	<bean id="homeAddrId" class="com.itheima.f_xml.b_setter.Address">
		<property name="addr" value="阜南"></property>
		<property name="tel" value="911"></property>
	</bean>
	<bean id="companyAddrId" class="com.itheima.f_xml.b_setter.Address">
		<property name="addr" value="北京八宝山"></property>
		<property name="tel" value="120"></property>
	</bean>

1.3 P命令空间

对“setter方法注入”进行简化，替换，而是在
<bean p:属性名="普通值" p:属性名-ref="引用值">
p命名空间使用前提，必须添加命名空间

public class Person {
	private String pname;
	private Integer age;
	private Address homeAddr;
	private Address componyAddr;
	public String getPname() {
		return pname;
	}
	public void setPname(String pname) {
		this.pname = pname;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public Address getHomeAddr() {
		return homeAddr;
	}
	public void setHomeAddr(Address homeAddr) {
		this.homeAddr = homeAddr;
	}
	public Address getComponyAddr() {
		return componyAddr;
	}
	public void setComponyAddr(Address componyAddr) {
		this.componyAddr = componyAddr;
	}
	@Override
	public String toString() {
		return "Person [pname=" + pname + ", age=" + age + ", homeAddr="
				+ homeAddr + ", componyAddr=" + componyAddr + "]";
	}
	
	
}

public class Address {
	private String addr;
	private String tel;
	public String getAddr() {
		return addr;
	}
	public void setAddr(String addr) {
		this.addr = addr;
	}
	public String getTel() {
		return tel;
	}
	public void setTel(String tel) {
		this.tel = tel;
	}
	@Override
	public String toString() {
		return "Address [addr=" + addr + ", tel=" + tel + "]";
	}
	
}

<?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:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="
            http://www.springframework.org/schema/beans 
            http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean id="person" class="com.jdwa.spring.f_xml.c_p.Person" p:pname="zkn" p:age="22" 
		p:componyAddr-ref="componyAddr" p:homeAddr-ref="homeAddr" />
	<bean id="homeAddr" class="com.jdwa.spring.f_xml.c_p.Address" 
		p:addr="南京" p:tel="666"/>
	<bean id="componyAddr" class="com.jdwa.spring.f_xml.c_p.Address"
		p:addr="沈阳" p:tel="888"/>
</beans>

1.4.集合注入

public class CollData {
	private String[] arrayData;
	private List<String> listData;
	private Set<String> setData;
	private Map<String,String> mapData;
	private Properties propsData;
	public String[] getArrayData() {
		return arrayData;
	}
	public void setArrayData(String[] arrayData) {
		this.arrayData = arrayData;
	}
	public List<String> getListData() {
		return listData;
	}
	public void setListData(List<String> listData) {
		this.listData = listData;
	}
	public Set<String> getSetData() {
		return setData;
	}
	public void setSetData(Set<String> setData) {
		this.setData = setData;
	}
	public Map<String, String> getMapData() {
		return mapData;
	}
	public void setMapData(Map<String, String> mapData) {
		this.mapData = mapData;
	}
	public Properties getPropsData() {
		return propsData;
	}
	public void setPropsData(Properties propsData) {
		this.propsData = propsData;
	}
	@Override
	public String toString() {
		return "CollData [
arrayData=" + Arrays.toString(arrayData)
				+ ", 
listData=" + listData + ",
 setData=" + setData
				+ ", 
mapData=" + mapData + ",
 propsData=" + propsData + "
]";
	}
	
	
	
	
	
}

<?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.xsd">
	
	<bean id="collData" class="com.jdwa.spring.f_xml.e_coll.CollData">
		<property name="arrayData">
			<array>
				<value>array1</value>
				<value>array2</value>
				<value>array3</value>
			</array>
		</property>
		<property name="listData">
			<list>
				<value>list1</value>
				<value>list2</value>
				<value>list3</value>
			</list>
		</property>
		<property name="setData">
			<set>
				<value>set1</value>
				<value>set2</value>
				<value>set3</value>
			</set>
		</property>
		<property name="mapData">
			<map>
				<entry key="map-key1" value="map-val1"></entry>
				<entry key="map-key2" value="map-val2"></entry>
				<entry key="map-key3" value="map-val3"></entry>
			</map>
		</property>
		<property name="propsData">
			<props>
				<prop key="prop-key1">prop-val1</prop>
				<prop key="prop-key2">prop-val2</prop>
				<prop key="prop-key3">prop-val3</prop>
			</props>
		</property>
	</bean>
</beans>

五、装配Bean 基于注解

@Component取代
@Component("id") 取代
2.web开发，提供3个@Component注解衍生注解（功能一样）取代
@Repository ：dao层
@Service：service层
@Controller：web层
3.依赖注入，给私有字段设置，也可以给setter方法设置
普通值：@Value("")
引用值：
方式1：按照【类型】注入
@Autowired
方式2：按照【名称】注入1
@Autowired
@Qualifier("名称")
方式3：按照【名称】注入2
@Resource("名称")
4.生命周期
初始化：@PostConstruct
销毁：@PreDestroy
5.作用域
@Scope("prototype") 多例

注解使用前提，添加命名空间，让spring扫描含有注解类
xmlns:context="http://www.springframework.org/schema/context"
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
<context:component-scan base-package="【包名】"></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"
       xsi:schemaLocation="
			http://www.springframework.org/schema/beans 
			http://www.springframework.org/schema/beans/spring-beans.xsd
			http://www.springframework.org/schema/context
			http://www.springframework.org/schema/context/spring-context.xsd">
		
		 <context:component-scan base-package="【包名】"></context:component-scan>
</beans>

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原文地址：https://www.cnblogs.com/caozz/p/11070519.html