Spring学习笔记之基础、IOC、DI（1）
时间:2022-06-22
本文章向大家介绍Spring学习笔记之基础、IOC、DI（1），主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项，具有一定的参考价值，需要的朋友可以参考一下。
0.0 Spring基本特性 Spring是一个开源框架；是基于Core来架构多层JavaEE系统 1.0 IOC 控制反转：把对象的创建过程交给spring容器来做。
1.1 applicationContext.xml
beans 存放了很多个类
把一个类放入到spring容器中，该类就是bean
一个bean就是描述一个类
id就是标示符
命名规范：类的第一个字母变成小写，其他的字母保持不变
class为类的全名
1.2 别名，模块别名<alias name="helloWorld" alias="雷">1.3 对象的创建方式
1.3.1 无参构造函数。(多数使用)<bean id=“personService" class="com.demo.bean.impl.PersonServiceImpl"/>/**
* spring容器在默认的情况下使用默认的构造函数创建对象
*/
@Test
public void testCreateObject_Default(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld");
helloWorld.hello();
} 1.3.2 静态工厂。<bean id="helloWorld2"
class="come.demo.spring.ioc.createobject.method.HelloWorldFactory"
factory-method="getInstance"></bean>
public class HelloWorldFactory {
public static HelloWorld getInstance(){
return new HelloWorld();
}
}
/**
* 在spring容器 内部，调用了HelloWorldFactory中的getInstance方法
* 而该方法的内容就是创建对象的过程，是由程序员来完成
*/
@Test
public void testCreateObject_StaticFactory(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld2");
helloWorld.hello();
} 1.3.3 实例工厂。<bean id="helloWorldFactory" class="come.demo.spring.ioc.createobject.method.HelloWorldFactory2"></bean>
<!--
factory-bean指向了实力工厂的bean
factory-method实例工厂对象的方法
-->
<bean id="helloWorld3" factory-bean="helloWorldFactory" factory-method="getInstance"></bean>public class HelloWorldFactory2 {
public HelloWorld getInstance(){
return new HelloWorld();
}
}
/**
* 实例工厂
* 1、spring容器创建一个实例工厂bean
* 2、该bean调用了工厂方法getInstance产生对象
*/
@Test
public void testCreateObject_InstanceFactory(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld3");
helloWorld.hello();
}1.4 范围
1.4.1 在默认情况下，spring容器产生的对象是单例的 <bean id="helloWorld"
class="come.demo.spring.ioc.scope.HelloWorld"></bean>public class HelloWorld {
public HelloWorld(){
System.out.println("new instance");
}
public void hello(){
System.out.println("hello world");
}
} @Test
public void testScope_Default(){
ApplicationContext context
= new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld");
System.out.println(helloWorld);
HelloWorld helloWorld2 = (HelloWorld)context.getBean("helloWorld");
System.out.println(helloWorld2);
} 1.4.2 如果scope为"prototype"，则为多实例<bean id="helloWorld"
class="come.demo.spring.ioc.scope.HelloWorld"
scope="prototype"></bean>
@Test
public void testScope_Prototype(){
ApplicationContext context
= new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld");
HelloWorld helloWorld2 = (HelloWorld)context.getBean("helloWorld");
} 1.4.3 larzyscope
如果scope为"prototype"，多例。
那么lazy-init属性将失去作用@Test
public void testScope_Prototype_Lazy_Default(){
ApplicationContext context
= new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld");
HelloWorld helloWorld2 = (HelloWorld)context.getBean("helloWorld");
System.out.println(helloWorld);
System.out.println(helloWorld2);
} 1.4.4 spring创建对象的时间。
1.0 默认（一般更安全，若果spring配置文件有错误，在启动spring容器时就会报错）<bean id="helloWorld"
class="come.demo.spring.ioc.scope.HelloWorld"></bean> 1.1 加载spring容器
1.2 spring容器调用默认的构造函数为bean创造对象
1.3 利用context.getBean把对象取出来
2.0 lazy-init=“true" ，在启动spring容器的时候是发现不了错误的<bean id="helloWorld"
class="come.demo.spring.ioc.scope.HelloWorld"
lazy-init="true"></bean> 2.1 启动spring容器
2.2 执行context.getBean
2.3 spring容器为该bean创建对象
1.5 ioc和destory
1.5.1 applicationContext.xml<!--
destroy-method 销毁该对象的方法
-->
<bean id="helloWorld"
class="come.demo.spring.ioc.initdestroy.HelloWorld"
init-method="init"
destroy-method="destroy"
scope="prototype"></bean> 1.5.2 HelloWorldpublic class HelloWorld {
public HelloWorld(){
System.out.println("new instance");
}
public void init(){
System.out.println("init");
}
public void destroy(){
System.out.println("detroy");
}
public void hello(){
System.out.println("hello world");
}
} 1.5.3 InitDestroyTest.javapublic class InitDestroyTest {
/**
* 1、启动spring容器
* 2、创建helloWorld对象
* 3、执行init方法 该方法是由spring容器内部调用
* 4、context.getBean把对象提取出来
* 5、对象调用方法
* 6、当执行close方法的时候，执行该对象的destroy方法 是由spring容器内部调用
*/
@Test
public void testInitDestroy_Scope_Default(){
ApplicationContext context = new
ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld");
helloWorld.hello();
ClassPathXmlApplicationContext applicationContext =
(ClassPathXmlApplicationContext)context;
applicationContext.close();
}
/**
* 1、启动spring容器
* 2、context.getBean把对象提取出来
* 3、创建helloWorld对象
* 4、执行init方法 该方法是由spring容器内部调用
* 5、对象调用方法
* 说明：不负责销毁
*/
@Test
public void testInitDestroy_Scope_Prototype(){
ApplicationContext context = new
ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld helloWorld = (HelloWorld)context.getBean("helloWorld");
helloWorld.hello();
ClassPathXmlApplicationContext applicationContext =
(ClassPathXmlApplicationContext)context;
applicationContext.close();
}
}2.0 DI(依赖注入)给属性赋值的过程就是依赖注入 2.1 DI setter 2.1.1 applicationContext.xml
<?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-2.5.xsd">
<bean id="person" class="come.demo.spring.di.xml.setter.Person">
<!--
property描述的就是bean中的属性
name属性就是描述属性的名称
value就是值 如果是基本属性(String)，就用value赋值
ref 如果是引用类型，用ref赋值
-->
<property name="pid" value="1"></property>
<property name="name" value="王二麻子"></property>
<property name="student" ref="student"></property>
<property name="lists">//装配，给list赋值的过程。
<list>
<value>list1</value>
<value>list2</value>
<!--
list中存放一个student对象
-->
<ref bean="student"/>
</list>
</property>
<property name="objects">
<list>
<value>obj1</value>
<ref bean="student"/>
</list>
</property>
<property name="sets">
<set>
<value>set1</value>
<ref bean="student"/>
</set>
</property>
<property name="map">
<map>
<entry key="m1">
<value>m1</value>
</entry>
<entry key="m2">
<ref bean="student"/>
</entry>
</map>
</property>
<property name="properties">
<props>
<prop key="p1">p1</prop>
<prop key="p2">p2</prop>
</props>
</property>
</bean>
<bean id="student" class="come.demo.spring.di.xml.setter.Student"
scope="prototype"></bean>
</beans>2.1.2 person.java
public class Person {
private Long pid;
private String name;
private Student student;//引用类型
private List lists;
private Set sets;//集合
private Map map;
private Object[] objects;//数组
private Properties properties;
public Person(){
System.out.println("person");
}
public Long getPid() {
return pid;
}
public void setPid(Long pid) {
this.pid = pid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public List getLists() {
return lists;
}
public void setLists(List lists) {
this.lists = lists;
}
public Set getSets() {
return sets;
}
public void setSets(Set sets) {
this.sets = sets;
}
public Map getMap() {
return map;
}
public void setMap(Map map) {
this.map = map;
}
public Object[] getObjects() {
return objects;
}
public void setObjects(Object[] objects) {
this.objects = objects;
}
public Properties getProperties() {
return properties;
}
public void setProperties(Properties properties) {
this.properties = properties;
}
@Override
public String toString() {
return "Person [pid=" + pid + ", name=" + name + ", student=" + student
+ ", lists=" + lists + ", sets=" + sets + ", map=" + map
+ ", objects=" + Arrays.toString(objects) + ", properties="
+ properties + "]";
}
}student.java
public class Student {
public Student(){
System.out.println("student");
}
public void say(){
System.out.println("student");
}
}2.1.3 Test.java
public class DIXMLSetterTest {
/**
* 1、启动spring容器
* 2、给person创建对象
* 3、给student创建对象
* 4、调用person的各个属性的setter方法赋值
* 5、context.getBean
* 6、对象调用方法
*/
@Test
public void testDI_XML_Setter_Default(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
@Test
public void testDI_XML_Setter_Person_Default_Student_Lazyinit_TRUE(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
/**
* 1、启动spring容器
* 2、创建Student对象
* 3、context.getBean
* 4、创建person对象
* 5、调用setter方法赋值
* 6、对象调用方法
*/
@Test
public void testDI_XML_Setter_Person_Lazyinit_TRUE_Student_Lazyinit_Default(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
/**
* 1、启动spring容器
* 2、创建Student对象
* 3、context.getBean
* 4、创建person对象
* 5、调用setter方法赋值
* 6、对象调用方法
*/
@Test
public void testDI_XML_Setter_Person_Scope_Prototype_Student_Scope_Default(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
/**
* 1、启动spring容器
* 2、创建person对象
* 3、创建student对象 student的scope为"prototype"，但是创建对象在spring容器启动的时候
* 因为Person中的很多属性都依赖于student,而这些属性的赋值发生在spring容器启动的时候
* 4、调用setter方法赋值
* 5、 context.getBean
* 6、对象调用方法
*/
@Test
public void testDI_XML_Setter_Person_Scope_Default_Student_Scope_Prototype(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
}2.2 Di的init、destroy执行顺序 2.2.1 applicationContext.xml
<?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-2.5.xsd">
<bean id="person" class="come.demo.spring.di.xml.setterinitdestroy.Person"
init-method="init">
<!--
property描述的就是bean中的属性
name属性就是描述属性的名称
value就是值 如果是基本属性(String)，就用value赋值
ref 如果是引用类型，用ref赋值
-->
<property name="pid" value="1"></property>
<property name="name" value="王二麻子"></property>
<property name="student" ref="student"></property>
<property name="lists">
<list>
<value>list1</value>
<value>list2</value>
<!--
list中存放一个student对象
-->
<ref bean="student"/>
</list>
</property>
<property name="objects">
<list>
<value>obj1</value>
<ref bean="student"/>
</list>
</property>
<property name="sets">
<set>
<value>set1</value>
<ref bean="student"/>
</set>
</property>
<property name="map">
<map>
<entry key="m1">
<value>m1</value>
</entry>
<entry key="m2">
<ref bean="student"/>
</entry>
</map>
</property>
<property name="properties">
<props>
<prop key="p1">p1</prop>
<prop key="p2">p2</prop>
</props>
</property>
</bean>
<bean id="student" class="come.demo.spring.di.xml.setterinitdestroy.Student"></bean>
</beans>2.2.2 java文件 Person.java
public class Person {
private Long pid;
private String name;
private Student student;
private List lists;
private Set sets;
private Map map;
private Object[] objects;
private Properties properties;
public void init(){
System.out.println("init");
}
public Person(){
System.out.println("person");
}
public Long getPid() {
return pid;
}
public void setPid(Long pid) {
this.pid = pid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
public List getLists() {
return lists;
}
public void setLists(List lists) {
this.lists = lists;
}
public Set getSets() {
return sets;
}
public void setSets(Set sets) {
this.sets = sets;
}
public Map getMap() {
return map;
}
public void setMap(Map map) {
this.map = map;
}
public Object[] getObjects() {
return objects;
}
public void setObjects(Object[] objects) {
this.objects = objects;
}
public Properties getProperties() {
return properties;
}
public void setProperties(Properties properties) {
this.properties = properties;
}
@Override
public String toString() {
return "Person [pid=" + pid + ", name=" + name + ", student=" + student
+ ", lists=" + lists + ", sets=" + sets + ", map=" + map
+ ", objects=" + Arrays.toString(objects) + ", properties="
+ properties + "]";
}
}Student.java
public class Student {
public Student(){
System.out.println("student");
}
public void say(){
System.out.println("student");
}
}2.2.3 TEST DIXMLSetterInitDetroyTest.java
public class DIXMLSetterInitDetroyTest {
/**
* 1、启动spring容器
* 2、实例化person,student
* 3、调用person的setter方法进行装配
* 4、调用person的init方法
* 5、context.getBean
* 6、person调用方法完成任务
*/
@Test
public void testDI_XML_Setter_InitDestroy(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
}2.3 DI的Setter和Constructor(构造器) 2.3.1 applicationContext.xml
<?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-2.5.xsd">
<bean id="person" class="come.demo.spring.di.xml.constructor.Person">
<!--
constructor-arg 代表某一个构造器的参数
index 构造器参数的下标
value
ref
type 类型
-->
<constructor-arg index="0" value="1" type="java.lang.String"></constructor-arg>
<constructor-arg index="1" ref="student"></constructor-arg>
</bean>
<bean id="student" class="come.demo.spring.di.xml.constructor.Student"></bean>
</beans>2.3.2 Person.java
public class Person {
private Long pid;
private String name;
private Student student;
private List lists;
private Set sets;
private Map map;
private Object[] objects;
private Properties properties;
//构造函数
public Person(Long pid,String name){
this.pid = pid;
this.name = name;
}
public Person(String name,Student student){
this.name = name;
this.student = student;
}
public void init(){
System.out.println("init");
}
@Override
public String toString() {
return "Person [pid=" + pid + ", name=" + name + ", student=" + student
+ ", lists=" + lists + ", sets=" + sets + ", map=" + map
+ ", objects=" + Arrays.toString(objects) + ", properties="
+ properties + "]";
}
}Student.java
public class Student {
public Student(){
System.out.println("student");
}
public void say(){
System.out.println("student");
}
}2.3.3 DIXMLSetterConstructorTest.java
public class DIXMLSetterConstructorTest {
@Test
public void testDI_XML_Constructor(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
Person person = (Person)context.getBean("person");
System.out.println(person.toString());
}
}2.3.4 如果person.java有set方法，则构造器和set均可以用 person.java
public class Person {
private Long pid;
private String name;
private Student student;
public Person(){}
public Person(String name,Student student){
this.name = name;
this.student = student;
}
public Long getPid() {
return pid;
}
public void setPid(Long pid) {
this.pid = pid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}
@Override
public String toString() {
return "Person [pid=" + pid + ", name=" + name + ", student=" + student
+ "]";
}
}2.4 IOC和DI的整合，完全的面向接口编程。Document实现。 applicationContext.xml
<?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-2.5.xsd">
<!--
把documentManager,wordDocument,excelDocument,pdfDocument放入到spring容器中
-->
<bean id="documentManager" class="come.demo.spring.di.xml.iocdi.setter.DocumentManager">
<!--
该属性是一个接口
-->
<property name="document">
<ref bean="excelDocument"/>
</property>
</bean>
<bean id="wordDocument" class="come.demo.spring.di.xml.iocdi.setter.WordDocument">
</bean>
<bean id="excelDocument" class="come.demo.spring.di.xml.iocdi.setter.ExcelDocument">
</bean>
<bean id="pdfDocument" class="come.demo.spring.di.xml.iocdi.setter.PDFDocument">
</bean>
</beans>Document.java
public interface Document {
public void read();
public void write();
}DocumentManager.java
public class DocumentManager {
/**
* 接口
*/
private Document document;
public DocumentManager(){}
public Document getDocument() {
return document;
}
public void setDocument(Document document) {
this.document = document;
}
public DocumentManager(Document document){
this.document = document;
}
public void read(){
//接口调用方法
this.document.read();
}
public void write(){
this.document.write();
}
}ExcelDocument.java
public class ExcelDocument implements Document{
public void read() {
// TODO Auto-generated method stub
System.out.println("excel read");
}
public void write() {
// TODO Auto-generated method stub
System.out.println("excel write");
}
}PDFDocument.java
public class PDFDocument implements Document{
public void read() {
// TODO Auto-generated method stub
System.out.println("pdf read");
}
public void write() {
// TODO Auto-generated method stub
System.out.println("pdf write");
}
}WordDocument.java
public class WordDocument implements Document{
public void read() {
// TODO Auto-generated method stub
System.out.println("word read");
}
public void write() {
// TODO Auto-generated method stub
System.out.println("word write");
}
}DocumentTest.java
public class DocumentTest {
@Test
public void testDocument_NO_Spring(){
/**
* 等号的左边是接口，等号的右边是实现类
*/
Document wordDocument = new WordDocument();
DocumentManager documentManager = new DocumentManager(wordDocument);
documentManager.read();
documentManager.write();
}
/**
* 在客户端做到了完全的面向接口编程,程序员再也不用在客户端关心document是由谁来实现的
*/
@Test
public void testDocument_Spring(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
DocumentManager documentManager = (DocumentManager)context.getBean("documentManager");
documentManager.read();
documentManager.write();
}
}2.5 IOC和DI整合，MVC实现。完全面向接口编程 applicationContext.xml
<?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-2.5.xsd">
<bean id="personDao" class="come.demo.spring.di.xml.iocdi.setter.mvc.PersonDaoImpl"></bean>
<bean id="personService" class="come.demo.spring.di.xml.iocdi.setter.mvc.PersonServiceImpl">
<property name="personDao">
<ref bean="personDao"/>
</property>
</bean>
<bean id="personAction" class="come.demo.spring.di.xml.iocdi.setter.mvc.PersonAction">
<property name="personService">
<ref bean="personService"/>
</property>
</bean>
</beans>PersonAction.java
public class PersonAction {
private PersonService personService;
public PersonService getPersonService() {
return personService;
}
public void setPersonService(PersonService personService) {
this.personService = personService;
}
public void savePerson(){
this.personService.savePerson();
}
}PersonDao.java
public interface PersonDao {
public void savePerson();
}PersonDaoImpl.java
public class PersonDaoImpl implements PersonDao{
public void savePerson() {
// TODO Auto-generated method stub
System.out.println("save person");
}
}PersonService.java
public interface PersonService {
public void savePerson();
}PersonServiceImpl.java
public class PersonServiceImpl implements PersonService{
private PersonDao personDao;
public PersonDao getPersonDao() {
return personDao;
}
public void setPersonDao(PersonDao personDao) {
this.personDao = personDao;
}
public void savePerson() {
// TODO Auto-generated method stub
this.personDao.savePerson();
}
}MVCTest.java
public class MVCTest {
@Test
public void testMVC(){
ApplicationContext context =
new ClassPathXmlApplicationContext("applicationContext.xml");
PersonAction personAction = (PersonAction)context.getBean("personAction");
personAction.savePerson();
}
}
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