Spring简介
Spring是Java的开源企业应用程序开发框架，它为 Java beans控制容器的翻转。最初由Rod Johnson在2003年6月基于Apache2.0许可证发布。
Spring框架处理底层，使我们能够专注于应用程序逻辑。 Spring能够从POJOs(Plain Old Java Objects)非侵入式的构建应用程序。比如：
•不需要处理servlet或servlet API，Java方法可以处理HTTP POST / GET请求。
•不需要处理web服务API，Java方法可提供RESTful Web服务
•不需要处理事务API，Java方法可以执行数据库事务
•不需要处理远程API，本地Java方法使用RPC(remote procedure call)
•不需要处理JMS API，Java方法可以使用和处理消息
•不需要处理JMX API，Java方法可以作为管理扩展
Spring的特性：
•开源应用程序框架
•企业轻量级应用框架
•非侵入性(基于POJO)
•模块化
•可扩展用于其他框架
•Java企业应用程序的事实标准
优势：
•使用POJO、轻，非入侵
•通过依赖注入和接口定向实现松耦合
•通过aspect和共同约定实现声明式编程
•通过aspect和模板减少代码
Spring Framework的核心容器：
• Core and Beans：提供IOC(Inversion of control)和DI(dependency injection)
• Context：类似JNDI(Java Naming and Directory Interface,Java命名和目录接口)，用于在框架中访问对象。
• 表示语言（Expression Language）：SpEL，用于查询和修改对象图并评估数学表达式。
AOP模块
AOP是Spring面向方面编程的实现。它解耦业务逻辑和日志、安全等基础代码。
instrumentation模块
提供instrumentation类支持，通过MBean展示容器资源和帮助JMX管理。
消息模块
包含Spring Integration项目的关键抽象如Message、MessageChannel和的MessageHandler。
数据访问模块
•JDBC：JDBC抽象层
•ORM：为流行的对象关系映射提供集成层API，包括JPA，JDO，Hibernate和iBATIS
•OXM：对象/ XML映射抽象层，实现了JAXB，Castor，XMLBeans的，JiBX和Xstream
•JMS：生产和消费消息
•事务：它支持programmatic和programmatic事务管理
web层
该网络层包括web，webmvc / servlet中，WebSocket和webmvc-portlet模块：
•Web：文件上传等基础组件。
•Webmvc：
•Portlet
•WebSocket
Spring项目涉及安全配置、Web应用程序、大数据、LDAP等。 Spring框架是其中一部分。
JNDI(Java Naming and Directory Interface,Java命名和目录接口)
Java相关的一些博客：
http://www.gualtierotesta.it/
IoC(Inversion of Control)和DI(dependency injection)经常不区分使用。IoC由IoC实现。
两种类型的依赖注入：
• Constructor injection
• Setter injection
比如定义：
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<bean id="bookLister" class="com.packt.di.BookLister">
<constructor-arg ref="bookService"/>
</bean>
<bean id="bookService" class="com.packt.di.BookServiceImpl" />
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等同于：
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BookService service = new BookServiceImpl();
BookLister bookLister = new BookLister(service);
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<bean id="bookListerSetterInjection" class="com.packt.di.BookLister">
<property name="bookService" ref="bookService" />
</bean>
<bean id="bookService" class="com.packt.di.BookServiceImpl" />
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等同于：
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BookService service = new BookServiceImpl();
BookLister bookLister = new BookLister();
bookLister.setBookService(service);
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Spring IoC container 即ApplicationContext。管理的容器叫bean，比如bookService就是bean，即Spring IoC container管理的对象。
bean的属性有：
class、name(即id)、scope、constructor-arg、properties、lazy-init(使用时才创建容器)、init-method 、destroy-method。
scope的取值有：
- singleton：每个bean实例一个容器。实际上是每个bean实例一个classloader。
- prototype：每个bean实例多个实例对象。
- request：每个bean实例一个HTTP request。
- session：每个bean实例一个HTTP session。
- global-session：每个bean实例一个全局HTTP session。
生命周期：
第一个实例
前提： Maven和STS安装OK，都可以从Eclipse 市场安装。
新建Spring Starter Project项目，
Name：SpringOverview 注明名字前后不要有空格。
Type：Maven
其他用默认配置。
原有默认的SpringOverviewApplication类内容如下:
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package com.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class SpringOverviewApplication {
public static void main(String[] args) {
SpringApplication.run(SpringOverviewApplication.class, args);
}
}
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删除包com.example下面的SpringOverviewApplication类。新建HelloWorld类：
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package com.example;
public class HelloWorld {
private String message;
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
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在src/main/resources新建 applicationContext.xml：
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<?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="helloWorld" class="com.example.HelloWorld">
<property name="message" value="Welcome to the Spring world">
</property>
</bean>
</beans>
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com.example下面新建类HelloWorldExample：
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package com.example;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class HelloWorldExample {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld world = (HelloWorld)
context.getBean("helloWorld");
System.out.println(world.getMessage());
}
}
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用Spring Boot App的方式执行：
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11:38:15.765 [main] DEBUG o.s.core.env.StandardEnvironment - Adding [systemProperties] PropertySource with lowest search precedence
11:38:15.768 [main] DEBUG o.s.core.env.StandardEnvironment - Adding [systemEnvironment] PropertySource with lowest search precedence
11:38:15.768 [main] DEBUG o.s.core.env.StandardEnvironment - Initialized StandardEnvironment with PropertySources [systemProperties,systemEnvironment]
11:38:15.770 [main] INFO o.s.c.s.ClassPathXmlApplicationContext - Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@71c7db30: startup date [Thu Dec 31 11:38:15 CST 2015]; root of context hierarchy
11:38:15.794 [main] DEBUG o.s.core.env.StandardEnvironment - Adding [systemProperties] PropertySource with lowest search precedence
11:38:15.795 [main] DEBUG o.s.core.env.StandardEnvironment - Adding [systemEnvironment] PropertySource with lowest search precedence
11:38:15.795 [main] DEBUG o.s.core.env.StandardEnvironment - Initialized StandardEnvironment with PropertySources [systemProperties,systemEnvironment]
11:38:15.801 [main] INFO o.s.b.f.xml.XmlBeanDefinitionReader - Loading XML bean definitions from class path resource [applicationContext.xml]
11:38:15.811 [main] DEBUG o.s.b.f.xml.DefaultDocumentLoader - Using JAXP provider [com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl]
11:38:15.830 [main] DEBUG o.s.b.f.xml.PluggableSchemaResolver - Loading schema mappings from [META-INF/spring.schemas]
11:38:15.833 [main] DEBUG o.s.b.f.xml.PluggableSchemaResolver - Loaded schema mappings: {http://www.springframework.org/schema/cache/spring-cache-4.2.xsd=org/springframework/cache/config/spring-cache-4.2.xsd, http://www.springframework.org/schema/aop/spring-aop-4.1.xsd=org/springframework/aop/config/spring-aop-4.1.xsd, http://www.springframework.org/schema/context/spring-context-3.1.xsd=org/springframework/context/config/spring-context-3.1.xsd, http://www.springframework.org/schema/util/spring-util-3.0.xsd=org/springframework/beans/factory/xml/spring-util-3.0.xsd, http://www.springframework.org/schema/tool/spring-tool.xsd=org/springframework/beans/factory/xml/spring-tool-4.2.xsd, http://www.springframework.org/schema/aop/spring-aop-3.2.xsd=org/springframework/aop/config/spring-aop-3.2.xsd, http://www.springframework.org/schema/lang/spring-lang-4.1.xsd=org/springframework/scripting/config/spring-lang-4.1.xsd, http://www.springframework.org/schema/context/spring-context-4.0.xsd=org/springframework/context/config/spring-context-4.0.xsd, http://www.springframework.org/schema/beans/spring-beans-4.2.xsd=org/springframework/beans/factory/xml/spring-beans-4.2.xsd, http://www.springframework.org/schema/tool/spring-tool-4.1.xsd=org/springframework/beans/factory/xml/spring-tool-4.1.xsd, http://www.springframework.org/schema/lang/spring-lang-3.2.xsd=org/springframework/scripting/config/spring-lang-3.2.xsd, http://www.springframework.org/schema/cache/spring-cache-3.2.xsd=org/springframework/cache/config/spring-cache-3.2.xsd, http://www.springframework.org/schema/jee/spring-jee-4.1.xsd=org/springframework/ejb/config/spring-jee-4.1.xsd, http://www.springframework.org/schema/util/spring-util-2.0.xsd=org/springframework/beans/factory/xml/spring-util-2.0.xsd, http://www.springframework.org/schema/task/spring-task-4.2.xsd=org/springframework/scheduling/config/spring-task-4.2.xsd, http://www.springframework.org/schema/tool/spring-tool-3.2.xsd=org/springframework/beans/factory/xml/spring-tool-3.2.xsd, http://www.springframework.org/schema/context/spring-context.xsd=org/springframework/context/config/spring-context-4.2.xsd, http://www.springframework.org/schema/cache/spring-cache-4.1.xsd=org/springframework/cache/config/spring-cache-4.1.xsd, http://www.springframework.org/schema/aop/spring-aop-4.0.xsd=org/springframework/aop/config/spring-aop-4.0.xsd, http://www.springframework.org/schema/jee/spring-jee-3.2.xsd=org/springframework/ejb/config/spring-jee-3.2.xsd, http://www.springframework.org/schema/context/spring-context-3.0.xsd=org/springframework/context/config/spring-context-3.0.xsd, http://www.springframework.org/schema/util/spring-util-2.5.xsd=org/springframework/beans/factory/xml/spring-util-2.5.xsd, http://www.springframework.org/schema/beans/spring-beans-3.2.xsd=org/springframework/beans/factory/xml/spring-beans-3.2.xsd, http://www.springframework.org/schema/aop/spring-aop-3.1.xsd=org/springframework/aop/config/spring-aop-3.1.xsd, http://www.springframework.org/schema/lang/spring-lang-4.0.xsd=org/springframework/scripting/config/spring-lang-4.0.xsd, http://www.springframework.org/schema/beans/spring-beans-4.1.xsd=org/springframework/beans/factory/xml/spring-beans-4.1.xsd, http://www.springframework.org/schema/tool/spring-tool-4.0.xsd=org/springframework/beans/factory/xml/spring-tool-4.0.xsd, http://www.springframework.org/schema/lang/spring-lang-3.1.xsd=org/springframework/scripting/config/spring-lang-3.1.xsd, http://www.springframework.org/schema/cache/spring-cache-3.1.xsd=org/springframework/cache/config/spring-cache-3.1.xsd, http://www.springframework.org/schema/jee/spring-jee-4.0.xsd=org/springframework/ejb/config/spring-jee-4.0.xsd, http://www.springframework.org/schema/task/spring-task-4.1.xsd=org/springframework/scheduling/config/spring-task-4.1.xsd, http://www.springframework.org/schema/tool/spring-tool-3.1.xsd=org/springframework/beans/factory/xml/spring-tool-3.1.xsd, http://www.springframework.org/schema/cache/spring-cache-4.0.xsd=org/springframework/cache/config/spring-cache-4.0.xsd, http://www.springframework.org/schema/jee/spring-jee-3.1.xsd=org/springframework/ejb/config/spring-jee-3.1.xsd, http://www.springframework.org/schema/util/spring-util-4.2.xsd=org/springframework/beans/factory/xml/spring-util-4.2.xsd, http://www.springframework.org/schema/task/spring-task-3.2.xsd=org/springframework/scheduling/config/spring-task-3.2.xsd, http://www.springframework.org/schema/beans/spring-beans-3.1.xsd=org/springframework/beans/factory/xml/spring-beans-3.1.xsd, http://www.springframework.org/schema/util/spring-util.xsd=org/springframework/beans/factory/xml/spring-util-4.2.xsd, http://www.springframework.org/schema/aop/spring-aop-3.0.xsd=org/springframework/aop/config/spring-aop-3.0.xsd, http://www.springframework.org/schema/beans/spring-beans-4.0.xsd=org/springframework/beans/factory/xml/spring-beans-4.0.xsd, http://www.springframework.org/schema/beans/spring-beans.xsd=org/springframework/beans/factory/xml/spring-beans-4.2.xsd, http://www.springframework.org/schema/lang/spring-lang-3.0.xsd=org/springframework/scripting/config/spring-lang-3.0.xsd, http://www.springframework.org/schema/context/spring-context-2.5.xsd=org/springframework/context/config/spring-context-2.5.xsd, http://www.springframework.org/schema/task/spring-task-4.0.xsd=org/springframework/scheduling/config/spring-task-4.0.xsd, http://www.springframework.org/schema/tool/spring-tool-3.0.xsd=org/springframework/beans/factory/xml/spring-tool-3.0.xsd, http://www.springframework.org/schema/aop/spring-aop-2.0.xsd=org/springframework/aop/config/spring-aop-2.0.xsd, http://www.springframework.org/schema/jee/spring-jee-3.0.xsd=org/springframework/ejb/config/spring-jee-3.0.xsd, http://www.springframework.org/schema/util/spring-util-4.1.xsd=org/springframework/beans/factory/xml/spring-util-4.1.xsd, http://www.springframework.org/schema/task/spring-task-3.1.xsd=org/springframework/scheduling/config/spring-task-3.1.xsd, http://www.springframework.org/schema/beans/spring-beans-3.0.xsd=org/springframework/beans/factory/xml/spring-beans-3.0.xsd, http://www.springframework.org/schema/jee/spring-jee.xsd=org/springframework/ejb/config/spring-jee-4.2.xsd, http://www.springframework.org/schema/aop/spring-aop-2.5.xsd=org/springframework/aop/config/spring-aop-2.5.xsd, http://www.springframework.org/schema/lang/spring-lang-2.0.xsd=org/springframework/scripting/config/spring-lang-2.0.xsd, http://www.springframework.org/schema/util/spring-util-3.2.xsd=org/springframework/beans/factory/xml/spring-util-3.2.xsd, http://www.springframework.org/schema/task/spring-task.xsd=org/springframework/scheduling/config/spring-task-4.2.xsd, http://www.springframework.org/schema/tool/spring-tool-2.0.xsd=org/springframework/beans/factory/xml/spring-tool-2.0.xsd, http://www.springframework.org/schema/lang/spring-lang-2.5.xsd=org/springframework/scripting/config/spring-lang-2.5.xsd, http://www.springframework.org/schema/context/spring-context-4.2.xsd=org/springframework/context/config/spring-context-4.2.xsd, http://www.springframework.org/schema/jee/spring-jee-2.0.xsd=org/springframework/ejb/config/spring-jee-2.0.xsd, http://www.springframework.org/schema/tool/spring-tool-2.5.xsd=org/springframework/beans/factory/xml/spring-tool-2.5.xsd, http://www.springframework.org/schema/jee/spring-jee-2.5.xsd=org/springframework/ejb/config/spring-jee-2.5.xsd, http://www.springframework.org/schema/util/spring-util-4.0.xsd=org/springframework/beans/factory/xml/spring-util-4.0.xsd, http://www.springframework.org/schema/task/spring-task-3.0.xsd=org/springframework/scheduling/config/spring-task-3.0.xsd, http://www.springframework.org/schema/aop/spring-aop-4.2.xsd=org/springframework/aop/config/spring-aop-4.2.xsd, http://www.springframework.org/schema/lang/spring-lang.xsd=org/springframework/scripting/config/spring-lang-4.2.xsd, http://www.springframework.org/schema/context/spring-context-3.2.xsd=org/springframework/context/config/spring-context-3.2.xsd, http://www.springframework.org/schema/util/spring-util-3.1.xsd=org/springframework/beans/factory/xml/spring-util-3.1.xsd, http://www.springframework.org/schema/beans/spring-beans-2.0.xsd=org/springframework/beans/factory/xml/spring-beans-2.0.xsd, http://www.springframework.org/schema/cache/spring-cache.xsd=org/springframework/cache/config/spring-cache-4.2.xsd, http://www.springframework.org/schema/lang/spring-lang-4.2.xsd=org/springframework/scripting/config/spring-lang-4.2.xsd, http://www.springframework.org/schema/context/spring-context-4.1.xsd=org/springframework/context/config/spring-context-4.1.xsd, http://www.springframework.org/schema/beans/spring-beans-2.5.xsd=org/springframework/beans/factory/xml/spring-beans-2.5.xsd, http://www.springframework.org/schema/tool/spring-tool-4.2.xsd=org/springframework/beans/factory/xml/spring-tool-4.2.xsd, http://www.springframework.org/schema/jee/spring-jee-4.2.xsd=org/springframework/ejb/config/spring-jee-4.2.xsd, http://www.springframework.org/schema/aop/spring-aop.xsd=org/springframework/aop/config/spring-aop-4.2.xsd}
11:38:15.833 [main] DEBUG o.s.b.f.xml.PluggableSchemaResolver - Found XML schema [http://www.springframework.org/schema/beans/spring-beans.xsd] in classpath: org/springframework/beans/factory/xml/spring-beans-4.2.xsd
11:38:15.862 [main] DEBUG o.s.b.f.x.DefaultBeanDefinitionDocumentReader - Loading bean definitions
11:38:15.871 [main] DEBUG o.s.b.f.xml.XmlBeanDefinitionReader - Loaded 1 bean definitions from location pattern [applicationContext.xml]
11:38:15.872 [main] DEBUG o.s.c.s.ClassPathXmlApplicationContext - Bean factory for org.springframework.context.support.ClassPathXmlApplicationContext@71c7db30: org.springframework.beans.factory.support.DefaultListableBeanFactory@4d95d2a2: defining beans [helloWorld]; root of factory hierarchy
11:38:15.888 [main] DEBUG o.s.c.s.ClassPathXmlApplicationContext - Unable to locate MessageSource with name 'messageSource': using default [org.springframework.context.support.DelegatingMessageSource@11758f2a]
11:38:15.889 [main] DEBUG o.s.c.s.ClassPathXmlApplicationContext - Unable to locate ApplicationEventMulticaster with name 'applicationEventMulticaster': using default [org.springframework.context.event.SimpleApplicationEventMulticaster@4671e53b]
11:38:15.890 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@4d95d2a2: defining beans [helloWorld]; root of factory hierarchy
11:38:15.890 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating shared instance of singleton bean 'helloWorld'
11:38:15.890 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Creating instance of bean 'helloWorld'
11:38:15.898 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Eagerly caching bean 'helloWorld' to allow for resolving potential circular references
11:38:15.914 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Finished creating instance of bean 'helloWorld'
11:38:15.915 [main] DEBUG o.s.c.s.ClassPathXmlApplicationContext - Unable to locate LifecycleProcessor with name 'lifecycleProcessor': using default [org.springframework.context.support.DefaultLifecycleProcessor@2f8f5f62]
11:38:15.915 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Returning cached instance of singleton bean 'lifecycleProcessor'
11:38:15.917 [main] DEBUG o.s.c.e.PropertySourcesPropertyResolver - Searching for key 'spring.liveBeansView.mbeanDomain' in [systemProperties]
11:38:15.917 [main] DEBUG o.s.c.e.PropertySourcesPropertyResolver - Found key 'spring.liveBeansView.mbeanDomain' in [systemProperties] with type [String] and value ''
11:38:15.919 [main] DEBUG o.s.b.f.s.DefaultListableBeanFactory - Returning cached instance of singleton bean 'helloWorld'
Welcome to the Spring world
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生命周期信息
ApplicationContextAware：实现setApplicationContext方法。
BeanNameAware：实现setBeanName方法。
InitializingBean：实现InitializingBean方法。
BeanFactoryAware：实现setBeanFactory方法。
BeanPostProcessor：实现postProcessBeforeInitialization和postProcessAfterInitialization方法。
DisposableBean：实现destroy方法。
在HelloWorld类中添加如下方法：
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public void myInit() {
System.out.println("custom myInit is called ");
}
public void myDestroy() {
System.out.println("custom myDestroy is called ");
}
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修改xml文件：
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<bean id="helloWorld" class="com.packt.lifecycle.HelloWorld"
init-method="myInit" destroy-method="myDestroy">
<property name="message" value="Welcome to the Spring world">
</property>
</bean>
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修改HelloWorldExample类
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public static void main(String[] args) {
AbstractApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
HelloWorld world = (HelloWorld) context.getBean("helloWorld");
context.getBean("helloWorld");
System.out.println(world.getMessage());
context.registerShutdownHook();
}
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现在执行可以看到“custom myInit is called ”等信息。
autowiring和注解
Spring容器可以自动处理bean之间的依赖关系，这样就没必要使用 <constructor-arg>和 <constructor-arg>标签，简化了应用程序上下文XML配置。
autowiring的类型如下：
•no：默认没有。
•byName：使用配置文件中相同名字的beans定义。
•byType的：使用配置文件中相同属性的beans定义。如果有多个则抛出异常。
•constructor：类似type，但基于构造类型。
•default：先使用constructor，不成功则基于byType。
修改applicationContext.xml：
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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
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
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.1.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
">
<context:annotation-config/>
<bean name="message" id="message" class="java.lang.String">
<constructor-arg value="auto wired" />
</bean>
<bean id="helloWorld" class="com.example.HelloWorld">
</bean>
</beans>
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注解类型如下：
•@Required：该注释适用于bean的setter方法
•@Autowired：bean的setter方法，构造函数和属性
•@Qualifier：和@Autowired一起用于限定bean。
通过<context:annotation-config/>开启autowiring的注解。
修改HelloWorld：
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package com.example;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
public class HelloWorld implements ApplicationContextAware,BeanNameAware, InitializingBean,
BeanFactoryAware,BeanPostProcessor, DisposableBean {
@Autowired
private String message;
public String getMessage() {
return message;
}
@Autowired
public void setMessage(String message) {
this.message = message;
}
public void setBeanName(String arg0) {
System.out.println("setBeanName is called with " + arg0);
}
@Override
public void afterPropertiesSet() throws Exception {
System.out.println("afterPropertiesSet is called ");
}
@Override
public void setBeanFactory(BeanFactory arg0) throws BeansException {
System.out.println("setBeanFactory is called ");
}
public void myInit() {
System.out.println("custom myInit is called ");
}
public void myDestroy() {
System.out.println("custom myDestroy is called ");
}
@Override
public void destroy() throws Exception {
System.out.println("destroy is called ");// TODO Auto-generated method stub
}
@Override
public Object postProcessAfterInitialization(Object arg0, String arg1)
throws BeansException {
System.out.println("postProcessAfterInitialization is called with "+arg0+" and "+arg1);
return null;
}
@Override
public Object postProcessBeforeInitialization(Object arg0, String arg1)
throws BeansException {
System.out.println("postProcessBeforeInitialization is called with "+arg0+" and "+arg1);
return null;
}
@Override
public void setApplicationContext(ApplicationContext arg0)
throws BeansException {
System.out.println("setApplicationContext is called ");
}
}
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现在执行可以看到”auto wired”信息。
aspect
AOP是Spring框架的关键组件之一。面向对象编程不能很好地处理一些通用功能。比如：
•日志记录和跟踪
•事务管理
•安全
•缓存
•错误处理
•性能监控
•自定义业务规则
•事件处理
AOP覆盖OOP的数据驱动层，用AspectJ和Spring AOP的实现：
•AspectJ：这是原来的AOP技术(从第一个版本的日期1995开始)，提供了全面的，面向方向的编程语言，使用字节码修改。
•Spring AOP的：基于Java的AOP框架，它使用动态代理，主要用来解决企业级问题。
•Join point连接点：插入逻辑的连接点。通常在：
°方法调用
°类初始化
°对象初始化
•Advice建议：连接点执行的代码。3种如下：
°before。
°after。
°around(兼具before和after的功能。
•Pointcut切入点：连接点的集合，通常是多个实际Join point的执行点。
•Aspect切面：实现横切，连接advice和Pointcut。一个应用可以有
任何数目的方面的，根据不同的要求。
•Weaving编织：应用到代码的过程，有三种类型：
°编译时
°类加载
°运行时
•目标：
•简介：修改该结构，引入额外的方法或字段。
有两种类型的AOP：
•静态AOP
°weaving是构建过程中的另一个步骤
°例如Java程序，可以过改变和修改应用程序的实际字节码
•动态AOP
°weaving在运行时动态地进行
°很容易改变的weaving过程而无需重新编译
Spring AOP是基于代理。关于代理的更多资料： http://en.wikipedia.org/wiki/Proxy_pattern，下面我们做个简单的演示：
创建接口IMessageWriter：
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package com.example;
public interface IMessageWriter {
void writeMessage();
}
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MessageWriter类实现IMessageWriter：
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package com.example;
public class MessageWriter implements IMessageWriter {
@Override
public void writeMessage() {
System.out.print("World");
}
}
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调用 writeMessage()是连接点。我们想把“World”把改成“ Hello World !”。MethodInterceptor是AOP标准接口。新建类MessageDecorator:
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package com.example;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
public class MessageDecorator implements MethodInterceptor {
public Object invoke(MethodInvocation invocation) throws Throwable {
System.out.print("Hello ");
Object retVal = invocation.proceed();
System.out.println("!");
return retVal;
}
}
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AOPTest类使用ProxyFactory类创建代理：
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package com.example;
import org.springframework.aop.framework.ProxyFactory;
public class AOPTest {
public static void main(String[] args) {
MessageWriter target = new MessageWriter();
// create the proxy
ProxyFactory pf = new ProxyFactory();
// Add the given AOP Alliance advice to the tail
// of the advice (interceptor) chain
pf.addAdvice(new MessageDecorator());
// Set the given object as target
pf.setTarget(target);
// Create a new proxy according to the
// settings in this factory
MessageWriter proxy = (MessageWriter) pf.getProxy();
// write the messages
target.writeMessage();
System.out.println("");
// use the proxy
proxy.writeMessage();
}
}
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Spring JDBC
Spring Data Access Object (DAO)支持统一的方式访问JDBC, Hibernate或JDO。Spring还可以处理异常，转换为未检查或者运行时。
DAO支持类如下：
• JdbcDaoSupport
• HibernateDaoSupport
• JdoDaoSupport
• JpaDaoSupport
通常的JDBC访问数据库代码如下：
1.定义连接参数。
2.打开连接。
3.指定的语句。
4.准备和执行该语句。
5.设置循环遍历结果（如果有的话）。
6.处理每个迭代。
7.处理异常。
8.处理事务。
9.关闭连接。
Spring简化为如下：
1.指定语句。
2.处理每个迭代。
Spring-JDBC事务框架包含如下包：
• org.springframework.jdbc.core
• org.springframework.jdbc.datasource
• org.springframework.jdbc.object
• org.springframework.jdbc.support
org.springframework.jdbc.core包含如下类：
• JdbcTemplate
• 不同的回调接口
• 其他相关类
org.springframework.jdbc.datasource包有以下类：
•便于数据源访问的工具类
•各种简单的DataSource实现，用于在J2EE容器之外测试和运行未修改的JDBC代码
•utility类提供静态方法从JNDI获得连接和必要时关闭连接。
•支持绑定线程的连接，例如DataSourceTransactionManager
org.springframework.jdbc.object包含以下内容：
•线程安全并可重用的数据库查询，更新和存储过程类
•这种方法是通过JDO模型，查询对象与数据库断开连接
•JDBC的高层抽象依赖于底层抽象org.springframework.jdbc.core。
该org.springframework.jdbc.support包包含以下内容：
•SQLException的转换功能和一些工具类
•转换异常
•使用Spring JDBC抽象层的代码不需要实现JDBC-或者RDBMS特定的错误处理
•所有unchecked异常。
JdbcTemplate类是org.springframework.jdbc.core的主类。它处理了资源创建和释放，简化了JDBC的使用。这有助于避免通用错误，如不关闭连接。它执行核心JDBC工作流，如语句创建和执行。
TestContext框架介绍
Spring的TestContext框架是一个通用的，注解驱动的框架，用于单元测试和集成测试。框架的资源位于org.springframework.test.context包，约定优于配置，每个配置都有默认值，通过注解可以修改非约定的配置。支持JUnit和TestNG，比如可以自定义JUnit执行器来支持非入侵的POJO测试类。
框架包含的类如下：
•TestContext: 该类提供在测试执行的上下文和上下文管理和缓存支持。加载应用程序上下文使用ContextLoader或SmartContextLoader接口。
•TestContextManager：框架的主入口点。它管理单个TestContext类和发布事件到TestExecutionListener实现。
这是测试执行要点：
°在静态类方法之前，
°在测试执行方法之前，
°在测试实例的准备
°测试执行方法之后
°在静态类方法之后
以下是接口：
•TestExecutionListener
•ContextLoader：这个接口加载集成测试的ApplicationContext
•SmartContextLoader：扩展ContextLoader接口，在Spring3.1引入，处理资源位置，注解类，或上下文初始化，还可以设置 active bean profiles ( @ActiveProfiles )和属性资源。
每个测试有一个TestContextManager类，它管理TestContext并处理 dependency injection, dirty checks, transactional support等。TestContextManager委派TestExecutionListener(通过dependency injection,managing transactions实现实际的测试执行)。
默认TestExecutionListener的实现方式注册方式如下：
• ServletTestExecutionListener： WebApplicationContext的Servlet API mock。
• DependencyInjectionTestExecutionListener
• DirtiesContextTestExecutionListener：检查上下文，确实测试执行时是否有脏bean。它还处理@DirtiesContext注解。
• TransactionalTestExecutionListener：这提供了事务性支持
•SqlScriptsTestExecutionListener：通过@sql注解执行SQL脚本
自定义TestExecutionListener
新建Spring maven新工程SpringTests。
新建类SpringTestsApplication：
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package com.example;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.TestContext;
import org.springframework.test.context.TestExecutionListener;
public class SysOutTestExecutionListener implements TestExecutionListener {
@Override
public void afterTestClass(TestContext testContext) throws Exception {
ApplicationContext ctx = testContext.getApplicationContext();
System.out.println("In afterTestClass for class = " + testContext.getTestClass());
}
@Override
public void afterTestMethod(TestContext testContext) throws Exception {
System.out.println("In afterTestMethod for = " + testContext.getTestMethod().getName());
}
@Override public void beforeTestClass(TestContext testContext) throws Exception {
System.out.println("In beforeTestClass for class = " + testContext.getTestClass());
}
@Override public void beforeTestMethod(TestContext testContext) throws Exception {
System.out.println("In beforeTestMethod for =" + testContext.getTestMethod().getName());
}
@Override
public void prepareTestInstance(TestContext testContext) throws Exception {
System.out.println("In prepareTestInstance for= " + testContext.getTestInstance());
}
}
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新建类：
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package com.example;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.TestExecutionListeners;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations="classpath:applicationContext.xml")
@TestExecutionListeners({SysOutTestExecutionListener.class})
public class TestExecutionListenerTest {
@Test
public void someTest() throws Exception {
System.out.println("executing someTest");
}
@Test
public void someOtherTest() throws Exception {
System.out.println("executing someOtherTest");
}
}
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新建文件：SpringTests/src/main/resources/applicationContext.xml
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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
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
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.1.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
">
</beans>
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配置Spring profile
Spring3.1引入了profile。它可以把一个包可以部署在各种环境中，如开dev, test, prod, perf等。
定义的系统属性spring.profiles.active，或使用 @ActiveProfiles注解测试类即可。
修改： applicationContext.xml
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<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-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">
<bean name="noProfileBean" id="message"
class="java.lang.String">
<constructor-arg value="I'm a free bean" />
</bean>
<beans profile="dev">
<bean name="message" id="message" class="java.lang.String">
<constructor-arg value="I'm a dev bean" />
</bean>
</beans>
<beans profile="prod">
<bean name="message" id="message" class="java.lang.String">
<constructor-arg value="I'm a prod bean" />
</bean>
</beans>
</beans>
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新建测试类：
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package com.example;
import static org.junit.Assert.*;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations="classpath:applicationContext.xml")
@ActiveProfiles(profiles={"dev"})
public class ProfileTest {
@Autowired
ApplicationContext context;
@Test
public void profile() throws Exception {
assertEquals("I'm a dev bean", context.getBean("message"));
//assertEquals("I'm a free bean", context.getBean("noProfileBean"));
}
}
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除了ActiveProfiles注解，也可以在环境变量中指定。比如spring.profiles.active = dev。
环境mock
后面补充
JNDI查找mock
后面补充
ReflectionTestUtils
org.springframework.test.util包的ReflectionTestUtils类包含不少反射方法，如设置非公开域或调用private/protected的setter方法等。
如下：
•ORM框架，如JPA和Hibernate
•Spring的注解支持，如@Autowired，@Inject，和@Resource，这对于private/protected域的提供依赖注入，setter方法和配置方法。
下面的示例演示ReflectionUtils的功能：
新增方法：Secret
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package com.example;
public class Secret {
private String secret;
public void initiate(String key) {
this.secret = key.replaceAll("a", "z").replaceAll("i", "k");
}
}
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测试代码
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package com.example;
import static org.junit.Assert.*;
import java.lang.reflect.Field;
import org.junit.Test;
import org.springframework.util.ReflectionUtils;
public class ReflectionUtilsTest {
@Test
public void private_field_access() throws Exception {
Secret myClass = new Secret();
myClass.initiate("aio");
Field secretField = ReflectionUtils.findField(Secret.class, "secret", String.class);
assertNotNull(secretField);
ReflectionUtils.makeAccessible(secretField);
assertEquals("zko", ReflectionUtils.getField(secretField, myClass));
ReflectionUtils.setField(secretField, myClass, "cool");
assertEquals("cool", ReflectionUtils.getField(secretField, myClass));
}
}
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public interface MyInterface {
// constant definition
String URL = "http://www.vogella.com";
// public abstract methods
void test();
void write(String s);
// default method
default String reserveString(String s){
return new StringBuilder(s).reverse().toString();
}
}
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public class MyClassImpl implements MyInterface {
@Override
public void test() {
}
@Override
public void write(String s) {
}
public static void main(String[] args) {
MyClassImpl impl = new MyClassImpl();
System.out.println(impl.reserveString("Lars Vogel"));
}
}
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public interface A {
default void m() {}
}
public interface B {
default void m() {}
}
public class C implements A, B {
@Override
public void m() {}
}
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public class C implements A, B {
@Override
public void m() {A.super.m();}
}
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