Java后端的学习之Spring基础-原创手记-慕课网

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.

效果

各种学习的知识点:

spring expression languagespring integrationspring web flowspring securityspring dataspring batch

spring网站:

http://spring.io/

效果

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

效果

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:

效果

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.

效果

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

效果

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">

spring.xml

测试:

import org.junit.Test;@RunWith(BlockJUnit4Cla***unner.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(BlockJUnit4Cla***unner.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;

}@Beforepublic 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");// ClasspathClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("classpath:spring-context.xml");// Web应用<listener>

<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>

<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>

// 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">

<constructor-arg name="DAO" ref="DAO"/>

</bean>

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">

// 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DAOpublic 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(BlockJUnit4Cla***unner.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(BlockJUnit4Cla***unner.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

@Repository用于注解DAO类为持久层

@Service用于注解Service类为服务层

@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

@Servicepublic class SimpleMovieLister { private MovieFinder movieFinder; @Autowired

public SimpleMovieLister(MovieFinder movieFinder){ this.movieFinder = movieFinder;

}

@Repositorypublic 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;@Autowiredpublic void setMovieFinder(MovieFinder movieFinder) { this.movieFinder = movieFinder;

}

用于构造器或成员变量@Autowiredprivate MovieCatalog movieCatalog;private CustomePreferenceDap customerPreferenceDao;@Autowiredpublic 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 iocspring aopspring ormspring mvcspring webservicespring transactionsspring jmsspring dataspring cachespring bootspring securityspring schedule

spring ioc为控制反转,控制反向,控制倒置,

效果

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

BeanFactoryBeanDefinition

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();

}

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

</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">

测试:

@Testpublic 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>

测试:

@Testpublic 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.javapublic class Server {

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

} public void putName(){

System.out.println(name);

}

// Main.javapublic 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></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/

效果

// xml<dependency>

<groupId>org.jvnet.localizer</groupId>

<artifactId>localizer</artifactId>

// pom.xml<repositories>

<url>https://maven.java.net/content/repositories/public/</url>

</repository></repositories>

Maven添加远程仓库:

// pom.xml<project ...><repositories>

<url>https://maven.java.net/content/repositories/public/</url>

</repository>

</repositories></project><project ...>

<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.

<groupId>junit</groupId>

<artifactId>junit</artifactId>

Maven打包:

<groupId>com.dashucoding</groupId>

<artifactId>NumberGenerator</artifactId>

<version>1.0-SNAPSHOT</version>

spring框架:

效果

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.javahelloworld->HelloWorld.java

HelloWorldService.java

impl实现类->

SpringHelloWorld.java

StrutsHelloWorld.javaresources->beans.xml// 总结

一个spring:HelloProgram.java

接口:

实现类:

资源:beans.xml

// HelloWorld.javapublic 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.javapublic class SpringHelloWorld implements HelloWorld {

@Override

public void sayHello() {

System.out.println("Spring Hello!");

}

}// StrutsHelloWorld.javapublic class StrutsHelloWorld implements HelloWorld {

@Override

public void sayHello() {

System.out.println("Struts Hello!");

}

// HelloProgram.javapublic 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">

</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.javaApplicationContext context = new ClassPathXmlApplicationContxt("beans.xml");

HelloWorldService service = (HelloWorldService) context.getBean("helloWorldService");

HelloWorld hw = service.getHelloWorld();

hw.sayHello();// HelloWorldServicepublic 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="">

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></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();

}