第65节：Java后端的学习之Spring基础

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Java后端的学习之Spring基础

如果要学习spring,那么什么是框架,spring又是什么呢?学习spring中的ioc和bean,以及aop,IOC,Bean,AOP,(配置,注解,api)-springFramework.

各种学习的知识点:

spring expression language
spring integration
spring web flow
spring security
spring data
spring batch


spring网站:

http://spring.io/

http://spring.io/projects/spring-framework

spring是一种开源框架,是为了解决企业应用开发的复杂性问题而创建的,现在的发展已经不止于用于企业应用了.

spring是一种轻量级的控制反转(IoC)和面向切面(AOP)的容器框架.

一句名言:spring带来了复杂的javaee开发的春天.

jdbc orm
oxm jms
transactions
websocket servlet
web portlet
aop aspects instrumentation messaging
beans core context spel


springmvc+spring+hibernate/ibatis->企业应用

什么是框架,为什么要用框架:

什么是框架:

框架就是别人制定好的一套规则和规范,大家在这个规范或者规则下进行工作,可以说,别人盖好了楼,让我们住.

软件框架是一种半成品,具有特定的处理流程和控制逻辑,成熟的,可以不断升级和改进的软件.

使用框架重用度高,开发效率和质量的提高,容易上手,快速解决问题.

spring ioc容器

接口,是用于沟通的中介物的,具有抽象化,java中的接口,就是声明了哪些方法是对外公开的.

面向接口编程,是用于隐藏具体实现的组件.

案例:

// 声明一个接口
public interface DemoInterface{
String hello(String text);
// 一个hello方法,接收一个字符串型的参数,返回一个`String`类型.
}
// 实现
public class OneInterface implements DemoInterface{
@Override
public String hello(String text){
return "你好啊: " + text;
}
}
// 测试类
public class Main{
public static void main(String[] args){
DemoInterface demo = new OneInterface();
System.out.println(demo.hello("dashucoding");
}
}


什么是IOC,IOC是控制反转,那么什么控制反转,控制权的转移,应用程序不负责依赖对象的创建和维护,而是由外部容器负责创建和维护.

<?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="oneInterface" class="com.ioc.interfaces.OneInterfaceImpl"></bean>
</beans>


spring.xml

测试:

import org.junit.Test;
@RunWith(BlockJUnit4ClassRunner.class)
public class TestOneInterface extends UnitTestBase {
public TestOneInterface(){
super("spring.xml");
}
@Test
public void testHello(){
OneInterface oneInterface = super.getBean("oneInterface");
System.out.println(oneInterface.hello("dashucoding"));
}
}


单元测试

下载一个包junit-*.jar导入项目中,然后创建一个UnitTestBase类,用于对spring进行配置文件的加载和销毁,所有的单元测试都是继承UnitTestBase的,然后通过它的getBean方法获取想要的对象,子类要加注解@RunWith(BlockJUnit4ClassRunner.class),单元测试方法加注解@Test.

public ClassPathXmlApplicationContext context;
public String springXmlpath;
public UnitTestBase(){}
public UnitTestBase(String springXmlpath){
this.springXmlpath = springXmlpath;
}
@Before
public void before(){
if(StringUtils.isEmpty(springXmlpath)){
springXmlpath = "classpath*:spring-*.xml";
}
try{
context = new ClassPathXmlApplicationContext(springXmlpath.split("[,\\s]+"));
context.start();
}catch(BeansException e){
e.printStackTrace();
}
}
@After
public void after(){
context.destroy();
}
@SuppressWarnings("unchecked")
protected <T extends Object> T getBean(String beanId){
return (T)context.getBean(beanId);
}
protected <T extends Object> T getBean(Class<T> clazz){
return context.getBean(clazz);
}
}


bean容器:

org.springframework.beans和org.springframework.context

BeanFactory提供配置结构和基本功能,加载并初始化Bean,ApplicationContext保存了Bean对象.

// 文件
FileSystemXmlApplicationContext context = new FileSystemXmlApplicationContext("D:/appcontext.xml");
// Classpath
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:spring-context.xml");
// Web应用
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>context</servlet-name>
<servlet-class>org.springframework.web.context.ContextLoaderServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>


spring注入:启动spring加载bean的时候,完成对变量赋值的行为.注入方式:设值注入和构造注入.

// 设值注入
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="iService" class="com.service.iServiceImpl">
<property name="iDAO" ref="DAO"/>
</bean>
<bean id="DAO" class="com.iDAOImpl"></bean>
</beans>


// 构造注入
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="iService" class="com.service.iServiceImpl">
<constructor-arg name="DAO" ref="DAO"/>
<property name="injectionDAO" ref="injectionDAO"></property>
</bean>
<bean id="DAO" class="com.iDAOImpl"></bean>
</beans>


spring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"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="injectionService" class="com.injection.service.InjectionServiceImpl"></bean>
<bean id="injectionDAO" class="com.ijection.dao.InjectionDAOImpl"></bean>
</beans>


// 接口-业务逻辑
public interface InjectionService {
public void save(String arg);
}


// 实现类-处理业务逻辑
public class InjectionServiceImpl implements InjecionService {
private InjectionDAO injectionDAO;
public InjectionServiceImpl(InjectionDAO injectionDAO) {
this.injectionDAO = injectionDAO;
}
public void setInjectionDAO(InjectiionDAO injectionDAO) {
this.injectionDAO = injectionDAO;
}
public void save(String arg) {
System.out.println("接收" + arg);
arg = arg + ":" + this.hashCode();
injectionDAO.save(arg);
}
}


// 接口-数据库-调用DAO
public interface InjectionDAO {
// 声明一个方法
public void save(String arg);
}


// 实现类
public class InjectionDAOImpl implements InjectionDAO {
// 实现接口中的方法
public void save(String arg) {
System.out.println("保存数据" + arg);
}
}


// 测试
import org.junit.Test;
@RunWith(BlockJUnit4ClassRunner.class)
public class TestInjection extends UnitTestBase {
public TestInjection(){
super("classpath:spring-injection.xml");
}
@Test
public void testSetter(){
InjectionService service = super.getBean("injectionService");
service.save("保存的数据");
}
@Test
public void testCons() {
InjectionService service = super.getBean("injectionService");
service.save("保存的数据");
}
}


bean的配置:

id:id是整个ioc容器中,bean的标识
class:具体要实例化的类
scope:作用域
constructor arguments:构造器的参数
properties:属性
autowiring mode:自动装配的模式
lazy-initialization mode:懒加载模式
Initialization/destruction method:初始化和销毁的方法


作用域

singleton:单例
prototype:每次请求都创建新的实例
request:每次http请求都创建一个实例有且当前有效
session:同上


spring bean配置之Aware接口:spring中提供了以Aware结尾的接口,为spring的扩展提供了方便.

bean的自动装配autowiring

no是指不做任何操作
byname是根据自己的属性名自动装配
byType是指与指定属性类型相同的bean进行自动装配,如果有过个类型存在的bean,那么就会抛出异常,不能使用byType方式进行自动装配,如果没有找到,就不什么事都不会发生
Constructor是与byType类似,它是用于构造器参数的,如果没有找到与构造器参数类型一致的bean就会抛出异常


spring bean配置的resource

resources:
urlresource是url的资源
classpathresource是获取类路径下的资源
filesystemresource是获取文件系统的资源
servletcontextresource是servletcontext封装的资源
inputstreamresource是针对输入流封装的资源
bytearrayresource是针对字节数组封装的资源


public interface ResourceLoader{
Resource getResource(String location);
}


ResourceLoader

classpath: Loaded from the classpath;
file: Loaded as a URL, from the filesystem;
http: Loaded as a URL;


案例:

public class MResource implements ApplicationContextAware{
private ApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
public void resource(){
Resource resource = applicationContext.getResource("classpath:config.txt");
System.out.println(resource.getFilename());
}
}


// 单元测试类
import com.test.base.UnitTestBase;
@RunWith(BlockJUnit4ClassRunner.class)
public class TestResource extends UnitTestBase {
public TestResource() {
super("classpath:spring-resource.xml");
}
@Test
public void testResource() {
MResource resource = super.getBean("mResource");
try{
resource.resource();
}catch(IOException e){
e.printStackTrace();
}
}
}


<?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="moocResource" class="com.resource.MResource"></bean>
</beans>


bean的定义与学习:

<context:annotation-config/>
@Component,@Repository,@Service,@Controller
@Required,@Autowired,@Qualifier,@Resource


@Configuration,@Bean,@Import,@DependsOn
@Component,@Repository,@Service,@Controller


1. @Repository用于注解DAO类为持久层
2. @Service用于注解Service类为服务层
3. @Controller用于Controller类为控制层

元注解Meta-annotations是spring提供的注解可以作为字节的代码叫元数据注解,处理value(),元注解可以有其他的属性.

spring可以自动检测和注册bean

@Service
public class SimpleMovieLister {
private MovieFinder movieFinder;
@Autowired
public SimpleMovieLister(MovieFinder movieFinder){
this.movieFinder = movieFinder;
}
}


@Repository
public class JpaMovieFinder implements MovieFinder {}


类的自动检测以及Bean的注册

<?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">
<context:component-scan base-package="org.example"/>
</beans>


类被自动发现并注册bean的条件:

用@Component,@Repository,@Service,@Controller注解或者使用@Component的自定义注解


@Required用于bean属性的setter方法

@Autowired注解

private MovieFinder movieFinder;
@Autowired
public void setMovieFinder(MovieFinder movieFinder) {
this.movieFinder = movieFinder;
}
用于构造器或成员变量
@Autowired
private MovieCatalog movieCatalog;
private CustomePreferenceDap customerPreferenceDao;
@Autowired
public MovieRecommender(CustomerPreferenceDao customerPreferenceDao) {
this.customerPreferenceDao = customerPreferenceDao;
}


@Autowired注解

使用这个注解,如果找不到bean将会导致抛出异常,可以使用下面代码避免,每个类只能有一个构造器被标记为required=true.

public class SimpleMovieLister {
private MovieFinder movieFinder;
@Autowired(required=false)
public void setMovieFinder(MovieFinder movieFinder){
this.movieFinder = movieFinder;
}
}


spring是一个开源框架，spring是用j2ee开发的mvc框架，spring boot呢就是一个能整合组件的快速开发框架，因为使用maven管理，所以很便利。至于spring cloud，就是微服务框架了。

spring是一个轻量级的Java开发框架,是为了解决企业应用开发的复杂性而创建的框架,框架具有分层架构的优势.

spring这种框架是简单性的,可测试性的和松耦合的,spring框架,我们主要是学习控制反转IOC和面向切面AOP.

// 知识点
spring ioc
spring aop
spring orm
spring mvc
spring webservice
spring transactions
spring jms
spring data
spring cache
spring boot
spring security
spring schedule


spring ioc为控制反转,控制反向,控制倒置,

Spring容器是 Spring 框架的核心。spring容器实现了相互依赖对象的创建,协调工作,对象只要关系业务逻辑本身,IOC最重要的是完成了对象的创建和依赖的管理注入等,控制反转就是将代码里面需要实现的对象创建,依赖的代码,反转给了容器,这就需要创建一个容器,用来让容器知道创建对象与对象的关系.(告诉spring你是个什么东西，你需要什么东西)

xml,properties等用来描述对象与对象间的关系
classpath,filesystem,servletContext等用来描述对象关系的文件放在哪里了.


控制反转就是将对象之间的依赖关系交给了容器管理,本来是由应用程序管理的对象之间的依赖的关系.

spring ioc体系结构

BeanFactory
BeanDefinition


spring ioc是spring的核心之一,也是spring体系的基础,在spring中主要用户管理容器中的bean.spring的IOC容器主要使用DI方式实现的.BeanFactory是典型的工厂模式,ioc容器为开发者管理对象间的依赖关系提供了很多便利.在使用对象时,要new object()来完成合作.ioc:spring容器是来实现这些相互依赖对象的创建和协调工作的.(由spring`来复杂控制对象的生命周期和对象间的)

所有的类的创建和销毁都是由spring来控制,不再是由引用它的对象了,控制对象的生命周期在spring.所有对象都被spring控制.

ioc容器的接口(自己设计和面对每个环节):

BeanFactory工厂模式

public interface BeanFactory {
String FACTORY_BEAN_PREFIX = "&";
Object getBean(String name) throws BeansException;
Object getBean(String name, Class requiredType) throws BeansException; boolean containsBean(String name);
boolean isSingleton(String name) throws NoSuchBeanDefinitionException;
Class getType(String name) throws NoSuchBeanDefinitionException;
String[] getAliases(String name);
}


BeanFactory三个子类:ListableBeanFactory,HierarchicalBeanFactory和AutowireCapableBeanFactory,实现类是DefaultListableBeanFactory.

控制反转就是所有的对象都被spring控制.ioc动态的向某个对象提供它所需要的对象.通过DI依赖注入来实现的.如何实现依赖注入ID,在Java中有一特性为反射,它可以在程序运行的时候进行动态的生成对象和执行对象的方法,改变对象的属性.

public static void main(String[] args){
ApplicationContext context = new FileSystemXmlApplicationContext("applicationContext.xml");
Animal animal = (Animal)context.getBean("animal");
animal.say();
}


// applicationContext.xml
<bean id="animal" class="com.test.Cat">
<property name="name" value="dashu"/>
</bean>


public class Cat implements Animal {
private String name;
public void say(){
System.out.println("dashu");
}
public void setName(String name){
this.name = name;
}
}


public interface Animal {
public void say();
}


// bean
private String id;
private String type;
private Map<String,Object> properties=new HashMap<String, Object>();


<bean id="test" class="Test">
<property name="testMap"> </property>
</bean>


public static Object newInstance(String className) {
Class<?> cls = null;
Object obj = null;
try {
cls = Class.forName(className);
obj = cls.newInstance();
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
} catch (InstantiationException e) {
throw new RuntimeException(e);
} catch (IllegalAccessException e) {
throw new RuntimeException(e);
}
return obj;
}


核心是控制反转（IOC）和面向切面（AOP）,spring是一个分层的JavaSE/EE的轻量级开源框架.

web:

struts,spring-mvc


service:

spring


dao:

mybatis,hibernate,jdbcTemplate,springdata


spring体系结构

ioc

// 接口
public interface UserService {
public void addUser();
}
// 实现类
public class UserServiceImpl implements UserService {
@Override
public void addUser(){
System.out.println("dashucoding");
}
}


配置文件:

<?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="userServiceId" class="com.dashucoding.UserServiceImpl"></bean>
</beans>


测试:

@Test
public void demo(){
String xmlPath = "com/beans.xml";
ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
UserService userService = (UserService) applicationContext.getBean("userServiceId");
userService.addUser();
}


依赖注入:

class DemoServiceImpl{
private daDao daDao;
}


创建service实例,创建dao实例,将dao设置给service.

接口和实现类:

public interface BookDao {
public void addBook();
}
public class BookDaoImpl implements BookDao {
@Override
public void addBook() {
System.out.println("dashucoding");
}
}


public interface BookService {
public abstract void addBook();
}
public class BookServiceImpl implements BookService {
private BookDao bookDao;
public void setBookDao(BookDao bookDao) {
this.bookDao = bookDao;
}
@Override
public void addBook(){
this.bookDao.addBook();
}
}


配置文件:

<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="bookServiceId" class="com.BookServiceImpl">
<property name="bookDao" ref="bookDaoId"></property>
</bean><bean id="bookDaoId" class="com.BookDaoImpl"></bean>
</beans>


测试:

@Test
public void demo(){
String xmlPath = "com/beans.xml";
ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
BookService bookService = (BookService) applicationContext.getBean("bookServiceId");bookService.addBook();
}


IDE建立Spring项目

File—>new—>project—>Spring


spring

// Server.java
public class Server {
privete String name;
public void setName(String name){
this.name = name;
}
public void putName(){
System.out.println(name);
}
}


// Main.java
public class Main{
public static void main(String[] args){
ApplicationContext context = new ClassPathXmlApplicationContext("spring-config.xml");
Server hello = (Server)context.getBean("example_one");
hello.putName();
}
}


spring-config.xml:

<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="example_one" class="Server">
<property name="name" value="达叔小生"></property>
</bean>
</beans>


使用Maven来声明Spring库.Maven是一个项目管理的工具,maven提供了开发人员构建一个完整的生命周期框架.Maven的安装和配置,需要的是JDK 1.8,Maven,Windows,配置jdk,JAVA_HOME变量添加到windows环境变量.下载Apache Maven,添加 M2_HOME 和 MAVEN_HOME,添加到环境变量PATH,值为%M2_HOME%\bin.执行mvn –version命令来显示结果.

Maven启用代理进行访问,找到文件路基,找到/conf/settings.xml,填写代理,要阿里的哦.

Maven中央存储库地址:

https://search.maven.org/

// xml
<dependency>
<groupId>org.jvnet.localizer</groupId>
<artifactId>localizer</artifactId>
<version>1.8</version>
</dependency>


// pom.xml
<repositories>
<repository>
<id>java.net</id>
<url>https://maven.java.net/content/repositories/public/</url>
</repository>
</repositories>


Maven添加远程仓库:

// pom.xml
<project ...>
<repositories>
<repository>
<id>java.net</id>
<url>https://maven.java.net/content/repositories/public/</url>
</repository>
</repositories>
</project><project ...>
<repositories>
<repository>
<id>JBoss repository</id>
<url>http://repository.jboss.org/nexus/content/groups/public/</url>
</repository>
</repositories>
</project>


Maven依赖机制,使用Maven创建Java项目.

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>


Maven打包:

<project ...>
<modelVersion>4.0.0</modelVersion>
<groupId>com.dashucoding</groupId>
<artifactId>NumberGenerator</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>


spring框架:

public interface HelloWorld{
public void sayHello();
}
public class SpringHelloWorld implements HelloWorld {
public void sayHello(){
System.out.println("Spring Hello");
}
}public class StrutsHelloWorld implements HelloWorld {
public void sayHello(){
System.out.println("Struts Hello");
}
}public class HelloWorldServie {
private HelloWorld helloWorld;
public HelloWorldService(){
this.helloWorld = new StrutsHelloWorld();
}
}


控制反转:

public class HelloWorldService{
private HelloWorld helloWorld;
public HelloWorldService(){
}
public void setHelloWorld(HelloWorld helloWorld){
this.helloWorld = helloWorld;
}
public HelloWorld getHelloWorld(){
return this.helloWorld;
}
}


ioc创建了HelloWorldService对象.

spring->HelloProgram.java
helloworld->
HelloWorld.java
HelloWorldService.java
impl实现类->
SpringHelloWorld.java
StrutsHelloWorld.java
resources->beans.xml
// 总结
一个spring:HelloProgram.java
接口:
实现类:
资源:beans.xml


// HelloWorld.java
public interface HelloWorld {
public void sayHello();
}
// public class HelloWorldService {
private HelloWorld helloWorld;
public HelloWorldService(){
}
public void setHelloWorld(HelloWorld helloWorld){
this.helloWorld = helloWorld;
}
public HelloWorld getHelloWorld(){
return this.helloWorld;
}
}


// SpringHelloWorld.java
public class SpringHelloWorld implements HelloWorld { @Override
public void sayHello() {
System.out.println("Spring Hello!");
}
}
// StrutsHelloWorld.java
public class StrutsHelloWorld implements HelloWorld { @Override
public void sayHello() {
System.out.println("Struts Hello!");
}
}


// HelloProgram.java
public class HelloProgram {
public static void main(String[] args) {
ApplicationContext context =
new ClassPathXmlApplicationContext("beans.xml");
HelloWorldService service =
(HelloWorldService) context.getBean("helloWorldService");
HelloWorld hw= service.getHelloWorld();
hw.sayHello();
}
}


// beans.xml
<beansxmlns="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="springHelloWorld"
class="com.spring.helloworld.impl.SpringHelloWorld"></bean>
<bean id="strutsHelloWorld"
class="com.spring.helloworld.impl.StrutsHelloWorld"></bean> <bean id="helloWorldService"
class="com.spring.helloworld.HelloWorldService">
<property name="helloWorld" ref="springHelloWorld"/>
</bean></beans>


<propertyname="helloWorld"ref="strutsHelloWorld"/>


ioc创建beans实现类springHelloWorld,创建一个helloWorldService类,beans.xml实现参数导入:

// helloWorldService
// springHelloWorld
// Hello Program.java
ApplicationContext context = new ClassPathXmlApplicationContxt("beans.xml");
HelloWorldService service = (HelloWorldService) context.getBean("helloWorldService");
HelloWorld hw = service.getHelloWorld();
hw.sayHello();// HelloWorldService
public class HelloWorldService {
private HelloWorld helloWorld;
public HelloWorldService(){
}
public void setHelloWorld(HelloWorld helloWorld){
this.helloWorld = helloWorld;
}
public HelloWorld = getHelloWorld() {
return this.helloWorld;
}
}


// beans.xml
<bean id="名称" class="路径"/>
<bean id="helloWorldService"
class="">
<property name="helloWorld" ref="springHelloWorld"/>
</bean>


spring库地址:

http://maven.springframework.org/release/org/springframework/spring/

hello-world:

public class HelloWorld {
private String name;
public void setName(String name) {
this.name = name;
}
public void printHello() {
System.out.println("Spring" + name);
}
}


// xml
<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="helloBean" class="">
<property name="name" value="dashu" />
</bean></beans>


// 执行
public class App {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext(
"applicationContext.xml");
HelloWorld obj = (HelloWorld) context.getBean("helloBean");
obj.printHello();
}
}


达叔小生：往后余生，唯独有你

You and me, we are family !

90后帅气小伙，良好的开发习惯；独立思考的能力；主动并且善于沟通

简书博客： 达叔小生

https://www.jianshu.com/u/c785ece603d1

结语

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