spring5.0学习笔记4

dependency injection DI
IOC的作用是削减程序间的耦合关系
依赖关系的管理都交给spring管理，即当前类要用到其他对象，由spring为我们提供，只需在配置文件中说明依赖关系，称之为依赖注入

能注入的数据有三类 基本数据类型String，其他bean类型，集合类型
注入方式有三种，使用构造函数提供，使用set方法提供，使用注解注入

<?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"
		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/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">	
<!-- 把创建对象交给spring管理 -->	
<!-- 1.使用构造函数注入	type index name value ref-->		
<bean id="accountService" class="com.test.AccountServiceImp">
	<constructor-arg index="0" value="xiaohua"></constructor-arg>
	<constructor-arg index="1" value="18"></constructor-arg>
	<constructor-arg index="2" ref="now"></constructor-arg>
</bean>

<bean id="now" class="java.util.Date"/>

<!-- set方法注入  常用，要求有默认构造函数-->
<bean id="accountService2" class="com.test.AccountServiceImp">
	<property name="name" value="张绍文"></property>
	<property name="age" value="33"></property>
	<property name="birthday" ref="now"></property>
</bean>

<!-- 注入集合 
	用于list的标签有list set array
	用于map的标签有map props
-->
<bean id="accountService3" class="com.test.AccountServiceImp">
	<property name="strs">
		<set>
			<value>aaa</value>
			<value>bbb</value>
			<value>ccc</value>
		</set>
	</property>
	
	<property name="list">
		<list>
			<value>aaa</value>
			<value>bbb</value>
			<value>ccc</value>
		</list>
	</property>
	
	<property name="set">
		<set>
			<value>aaa</value>
			<value>bbb</value>
			<value>ccc</value>
		</set>
	</property>
	
	<property name="map">
		<map>
			<entry key="testA" value="aaa"></entry>
			<entry key="testB" value="bbb"></entry>
			<entry key="testC" value="ccc"></entry>
		</map>
	</property>
	
	<property name="props">
		<props>
			<prop key="testC">ccc</prop>
			<prop key="testD">ddd</prop>
		</props>
	</property>
		
</bean>
</beans>

/**
 * 依赖注入
 */
package com.test;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;

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

public class Test{
    public static void main(String[] args){
    	//1.获取核心容器对象
    	ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
    	//2.根据id获取bean对象
    	IAccountService as = (IAccountService)ac.getBean("accountService");
    	System.out.println(as);
    	as.saveAccount();
    	IAccountService as2 = (IAccountService)ac.getBean("accountService2");
    	as2.saveAccount();
    	IAccountService as3 = (IAccountService)ac.getBean("accountService3");
    	as3.saveAccount();
    }
}

interface IAccountService{
	/**
	 * 模拟保存账户
	 */
	public void saveAccount();
}

/**
 * 业务层实现类
 */
class AccountServiceImp implements IAccountService{
	//若是经常变化的数据，并不适用配置文件注入的方式
	private String name;
	private Integer age;
	private Date birthday;
	
	private String[] strs;
	private List<String> list;
	private Set<String> set;
	private Map<String,String> map;
	private Properties props;
	public AccountServiceImp(String name,Integer age,Date birthday){
		this.name=name;
		this.age=age;
		this.birthday=birthday;
	}
	
	public AccountServiceImp(){
		
	}
	public void saveAccount(){
		 System.out.println("save a account"+name+" "+age+" "+birthday);
		 System.out.println(Arrays.toString(strs));
		 System.out.println(list);
		 System.out.println(set);
		 System.out.println(map);
		 System.out.println(props);
	 }

	public void setAge(Integer age) {
		this.age = age;
	}

	public void setBirthday(Date birthday) {
		this.birthday = birthday;
	}

	public void setName(String name) {
		this.name = name;
	}

	public void setList(List<String> list) {
		this.list = list;
	}

	public void setMap(Map<String, String> map) {
		this.map = map;
	}

	public void setProps(Properties props) {
		this.props = props;
	}

	public void setSet(Set<String> set) {
		this.set = set;
	}

	public void setStrs(String[] strs) {
		this.strs = strs;
	}
}

2020-3-24 23:43:55 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1ef9f1d: display name [org.springframework.context.support.ClassPathXmlApplicationContext@1ef9f1d]; startup date [Tue Mar 24 23:43:55 CST 2020]; root of context hierarchy
2020-3-24 23:43:55 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [bean.xml]
2020-3-24 23:43:55 org.springframework.context.support.AbstractApplicationContext obtainFreshBeanFactory
信息: Bean factory for application context [org.springframework.context.support.ClassPathXmlApplicationContext@1ef9f1d]: org.springframework.beans.factory.support.DefaultListableBeanFactory@bc8e1e
2020-3-24 23:43:55 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@bc8e1e: defining beans [accountService,now,accountService2,accountService3]; root of factory hierarchy
com.test.AccountServiceImp@b9e45a
save a accountxiaohua 18 Tue Mar 24 23:43:55 CST 2020
null
null
null
null
null
save a account张绍文 33 Tue Mar 24 23:43:55 CST 2020
null
null
null
null
null
save a accountnull null null
[aaa, bbb, ccc]
[aaa, bbb, ccc]
[aaa, bbb, ccc]
{testA=aaa, testB=bbb, testC=ccc}
{testD=ddd, testC=ccc}