Spring简单使用简介

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：

<bean id="bookLister" class="com.packt.di.BookLister">

<constructor-arg ref="bookService"/>

</bean>

<bean id="bookService" class="com.packt.di.BookServiceImpl" />

等同于：

1 2	`BookService service =` `new` `BookServiceImpl();` `BookLister bookLister =` `new` `BookLister(service);`

<bean id="bookListerSetterInjection" class="com.packt.di.BookLister">

<property name="bookService" ref="bookService" />

</bean>

<bean id="bookService" class="com.packt.di.BookServiceImpl" />

等同于：

BookService service = new BookServiceImpl();

BookLister bookLister = new BookLister();

bookLister.setBookService(service);

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:

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);

}

删除包com.example下面的SpringOverviewApplication类。新建HelloWorld类：

package com.example;

public class HelloWorld {

private String message;

public String getMessage() {

return message;

}

public void setMessage(String message) {

this.message = message;

}

在src/main/resources新建 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.xsd">

<bean id="helloWorld" class="com.example.HelloWorld">

<property name="message" value="Welcome to the Spring world">

</property>

</bean>

</beans>

com.example下面新建类HelloWorldExample：

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());

}

用Spring Boot App的方式执行：

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

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：

public void myInit() {

System.out.println("custom myInit is called ");

}

public void myDestroy() {

System.out.println("custom myDestroy is called ");

}

修改xml文件：

<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>

修改HelloWorldExample类

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();

}

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：

<?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>

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：

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 ");

}

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：

package com.example;

public interface IMessageWriter {

void writeMessage();

}

MessageWriter类实现IMessageWriter：

package com.example;

public class MessageWriter implements IMessageWriter {

@Override

public void writeMessage() {

System.out.print("World");

}

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:

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;

}

AOPTest类使用ProxyFactory类创建代理：

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();

}

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：

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());

}

新建类：

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");

}

新建文件：SpringTests/src/main/resources/applicationContext.xml

<?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>

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

<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>

新建测试类：

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"));

}

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

package com.example;

public class Secret {

private String secret;

public void initiate(String key) {

this.secret = key.replaceAll("a", "z").replaceAll("i", "k");

}

测试代码

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));

}

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();

}

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"));

}

public interface A {

default void m() {}

}

public interface B {

default void m() {}

}

public class C implements A, B {

@Override

public void m() {}

}

public class C implements A, B {

@Override

public void m() {A.super.m();}

}

文章由极客之音整理，本文链接：https://www.bmabk.com/index.php/post/14074.html

Spring简单使用简介

Spring简介

第一个实例

autowiring和注解

aspect

Spring JDBC

TestContext框架介绍

自定义TestExecutionListener

配置Spring profile

环境mock

JNDI查找mock

ReflectionTestUtils

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