SpringFramework(2)

 

一、Spring基础

1、核心

（1）IoC/Dependency Injection

l         IoC/Dependency Injection（依赖注入）：Beans不依赖于框架；容器注入依赖

l         轻量级Spring容器：配置和管理Beans

（2）BeanFactory

l         轻量级Bean容器

l         载入Bean定义，包括：

?         id/name

?         class

?         singleton或原型

?         属性

?         构造参数

?         初始化方法

?         析构方法

（3）XmlBeanFactory

l         BeanFactory实现

l         Beans定义的例子：

<beans>

<bean id="exampleBean" class="eg.ExampleBean"/>

<bean id="anotherExample" class="eg.ExampleBeanTwo"/>

</beans>

l         使用的例子：

InputStream input = new FileInputStream("beans.xml");

BeanFactory factory = new XmlBeanFactory(input);

ExampleBean eb = (ExampleBean)factory.getBean("exampleBean");

ExampleBeanTwo eb2 = (ExampleBeanTwo)factory.getBean("anotherExample");

可能会抛出NoSuchBeanDefinitionException；

ExampleBean eb = (ExampleBean)factory.getBean("exampleBean", ExampleBean.class);

可能会抛出BeanNotOfRequiredTypeException；

（4）Bean协作者

l         你的Bean工作所需要的其它Bean

package eg;

public class ExampleBean {

private AnotherBean beanOne;

private YetAnotherBean beanTwo;

public void setBeanOne(AnotherBean b) { beanOne = b; }

public void setBeanTwo(YetAnotherBean b) { beanTwo = b; }

}

<bean id="exampleBean" class="eg.ExampleBean">

<property name="beanOne"><ref bean="anotherExampleBean"/></property>

<property name="beanTwo"><ref bean="yetAnotherBean"/></property>

</bean>

<bean id="anotherExampleBean" class="eg.AnotherBean"/>

<bean id="yetAnotherBean" class="eg.YetAnotherBean"/>

（5）Bean属性

l         设置Bean属性

package eg;

public class ExampleBean {

private String s;

private int i;

public void setStringProperty(String s) { this.s = s; }

public void setIntegerProperty(int i) { this.i = i; }

}

<bean id="exampleBean" class="eg.ExampleBean">

<property name="stringProperty"><value>Hi!</value></property>

<property name="integerProperty"><value>1</value></property>

</bean>

（6）属性编辑器

l         转换String类型为各种对象类型

l         实现java.beans.PropertyEditor

l         标准Java类型：Bool、Byte、Color、Double、Float、Font、Int、Long、Short、String

l         标准Spring类型：Class、File、Locale、Properties、StringArray、URL

l         定制Spring类型：CustomBoolean、CustomDate、CustomNumber、CustomStringTrimmer

（7）标准属性编辑器

l         例子：

<property name="intProperty"><value>7</value></property>

<property name="doubleProperty"><value>0.25</value></property>

<property name="booleanProperty"><value>true</value></property>

<property name="colorProperty"><value>0,255,0</value></property>

java.awt.Color是用RGB值来初始化的

（8）Spring属性编辑器

l         例子：

<property name="classProperty">

<value>java.lang.Object</value>

</property>

<property name="fileProperty">

<value>/home/ziba/file.txt</value>

</property>

<property name="localeProperty">

<value>pt_BR</value>

</property>

<property name="urlProperty">

<value>http://java.net</value>

</property>

<property name="stringArrayProperty">

<value>foo,bar,baz</value>

</property>

（9）定制属性编辑器

l         Date例子：

DateFormat fmt = new SimpleDateFormat("d/M/yyyy");

CustomDateEditor dateEditor = new CustomDateEditor(fmt, false);

beanFactory.registerCustomEditor(java.util.Date.class, dateEditor);

<property name="date"><value>19/2/2004</value></property>

l         StringTrimming例子：Trim字符串，转换空串为null值

StringTrimmerEditor trimmer = new StringTrimmerEditor(true);

beanFactory.registerCustomEditor(java.lang.String.class, trimmer);

<property name="string1"><value> hello </value></property>

<property name="string2"><value></value></property>

<property name="string2"><null/></property>

（10）java.util.Properties

l         Properties的例子：

<property name="propertiesProperty">

<value>

foo=1

bar=2

baz=3

</value>

</property>

<property name="propertiesProperty">

<props>

<prop key="foo">1</prop>

<prop key="bar">2</prop>

<prop key="baz">3</prop>

</props>

</property>

（11）java.util.List

l         List的例子：

<property name="listProperty">

<list>

<value>a list element</value>

<ref bean="otherBean"/>

<ref bean="anotherBean"/>

</list>

</property>

（12）java.util.Set

l         Set的例子：

<property name="setProperty">

<set>

<value>a set element</value>

<ref bean="otherBean"/>

<ref bean="anotherBean"/>

</set>

</property>

（13）java.util.Map

l         Map的例子：

<property name="mapProperty">

<map>

<entry key="yup an entry">

<value>just some string</value>

</entry>

<entry key="yup a ref">

<ref bean="otherBean"/>

</entry>

</map>

</property>

（14）构造方法

l         构造方法的例子：

public class ExampleBean {

private AnotherBean beanOne;

private YetAnotherBean beanTwo;

private int i;

public ExampleBean(AnotherBean b1, YetAnotherBean b2, int i) {

this.beanOne = b1;

this.beanTwo = b2;

this.i = i;

}

}

<bean id="exampleBean" class="eg.ExampleBean">

<constructor-arg><ref bean="anotherExampleBean"/></constructor-arg>

<constructor-arg><ref bean="yetAnotherBean"/></constructor-arg>

<constructor-arg><value>1</value></constructor-arg>

</bean>

<bean id="anotherExampleBean" class="eg.AnotherBean"/>

<bean id="yetAnotherBean" class="eg.YetAnotherBean"/>

（15）Bean生命周期

l         Beans在它第一次使用时，能够被factory初始化

public class ExampleBean {

public void init() {

// do some initialization work

}

}

<bean id="exampleBean" class="eg.ExampleBean" init-method="init"/>

l         Beans在不再使用时，能够被清除

public class ExampleBean {

public void cleanup() {

// do some destruction work

}

}

<bean id="exampleBean" class="eg.ExampleBean" destroy-method="cleanup"/>

（16）PropertyPlaceholderConfigurer

l         从外部Properties文件中并入属性

<bean id="dataSource"

class="org.apache.commons.dbcp.BasicDataSource"

destroy-method="close">

<property name="driverClassName">

<value>${jdbc.driverClassName}</value>

</property>

<property name="url"><value>${jdbc.url}</value></property>

<property name="username"><value>${jdbc.username}</value></property>

<property name="password"><value>${jdbc.password}</value></property>

</bean>

jdbc.properties

jdbc.driverClassName=org.hsqldb.jdbcDriver

jdbc.url=jdbc:hsqldb:hsql://production:9002

jdbc.username=sa

jdbc.password=root

l         安装Configurer

InputStream input = new FileInputStream("beans.xml");

XmlBeanFactory factory = new XmlBeanFactory(input);

Properties props = new Properties();

props.load(new FileInputStream("jdbc.properties"));

PropertyPlaceholderConfigurer cfg = new PropertyPlaceholderConfigurer();

cfg.setProperties(props);

cfg.postProcessBeanFactory(factory);

DataSource ds = (DataSource)factory.getBean("dataSource");

（17）MethodInvokingFactoryBean

l         暴露使用Singleton模式的Bean

package eg;

public class MySingleton {

private static MySingleton instance = new MySingleton();

private MySingleton() {}

public static MySingleton getInstance() {

return instance;

}

}

<bean name="mySingleton"

class="...beans.factory.config.MethodInvokingFactoryBean">

<property name="staticMethod">

<value>eg.MySingleton.getInstance</value>

</property>

</bean>

FactoryBean代表另一个类创建Bean

（18）FactoryBean引用

l         获得FactoryBean自己的引用：

MySingleton singleton = (MySingleton)ctx.getBean("mySingleton");

获得由factory创建的Bean

FactoryBean factory = (FactoryBean)ctx.getBean("&mySingleton");

获得factory

（19）高级特性

l         单例/原型

l         Autowiring：对于type，要求每种需要的类型具有单实例；对于name，要求匹配每个属性名字的Bean名字（对非简单属性）

l         依赖检查

l         BeanWrapper

l         InitializingBean/DisposableBean接口

l         BeanFactoryAware/BeanNameAware接口