参见:http://chenjumin./blog/355544
参见:http://chenjumin./blog/364904 参见:http://chenjumin./blog/996389
一、ApplicationContextAware接口 当一个类需要获取ApplicationContext实例时,可以让该类实现ApplicationContextAware接口。代码展示如下: - public class Animal implements ApplicationContextAware, BeanNameAware{
- private String beanName;
- private ApplicationContext applicationContext;
-
- public void setBeanName(String name) {
- this.beanName = name;
- }
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-
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- public void setApplicationContext(ApplicationContext applicationContext)throws BeansException {
- this.applicationContext = applicationContext;
- }
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- public void run(){
- System.out.println(beanName);
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- AnimalEvent event = new AnimalEvent(this, "老虎");
- applicationContext.publishEvent(event);
- }
- }
通过@Autowired注解可以自动装配一些常用对象实例: - @Autowired
- private MessageSource messageSource;
-
- @Autowired
- private ResourceLoader resourceLoader;
-
- @Autowired
- private ApplicationContext applicationContext;
二、ApplicationEvent抽象类 当需要创建自定义事件时,可以新建一个继承自ApplicationEvent抽象类的类。代码展示如下: -
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- public class AnimalEvent extends ApplicationEvent {
- private String name;
-
- public String getName() {
- return name;
- }
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- public AnimalEvent(Object source){
- super(source);
- }
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- public AnimalEvent(Object source, String name){
- super(source);
- this.name = name;
- }
- }
三、ApplicationListener接口 当需要监听自定义事件时,可以新建一个实现ApplicationListener接口的类,并将该类配置到Spring容器中。代码展示如下: -
-
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- public class CustomEventListener implements ApplicationListener {
- public void onApplicationEvent(ApplicationEvent event) {
- if(event instanceof AnimalEvent){
- AnimalEvent animalEvent = (AnimalEvent)event;
- System.out.println("触发自定义事件:Animal name is " + animalEvent.getName());
- }
- }
- }
- <!-- 自定义事件监听器:Spring容器自动注册它 -->
- <bean id="customEventListener" class="com.cjm.spring.CustomEventListener"/>
要发布自定义事件,需要调用ApplicationContext的publishEvent方法,具体用法请看Animal类的源码。 四、BeanNameAware接口 当bean需要获取自身在容器中的id/name时,可以实现BeanNameAware接口。
五、InitializingBean接口 当需要在bean的全部属性设置成功后做些特殊的处理,可以让该bean实现InitializingBean接口。效果等同于bean的init-method属性的使用或者@PostContsuct注解的使用。 三种方式的执行顺序:先注解,然后执行InitializingBean接口中定义的方法,最后执行init-method属性指定的方法。
六、DisposableBean接口 当需要在bean销毁之前做些特殊的处理,可以让该bean实现DisposableBean接口。效果等同于bean的destroy-method属性的使用或者@PreDestory注解的使用。 三种方式的执行顺序:先注解,然后执行DisposableBean接口中定义的方法,最后执行destroy-method属性指定的方法。
七、BeanPostProcessor接口 当需要对受管bean进行预处理时,可以新建一个实现BeanPostProcessor接口的类,并将该类配置到Spring容器中。 实现BeanPostProcessor接口时,需要实现以下两个方法“ postProcessBeforeInitialization在受管bean的初始化动作之前调用 postProcessAfterInitialization在受管bean的初始化动作之后调用 容器中的每个Bean在创建时都会恰当地调用它们。代码展示如下: - public class CustomBeanPostProcessor implements BeanPostProcessor {
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- public Object postProcessBeforeInitialization(Object bean, String beanName)throws BeansException {
- System.out.println("postProcessBeforeInitialization: " + beanName);
- return bean;
- }
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- public Object postProcessAfterInitialization(Object bean, String beanName)throws BeansException {
- System.out.println("postProcessAfterInitialization: " + beanName);
- return bean;
- }
- }
-
- <bean id="customBeanPostProcessor" class="com.cjm.spring.CustomBeanPostProcessor"/>
八、BeanFactoryPostProcessor接口 当需要对Bean工厂进行预处理时,可以新建一个实现BeanFactoryPostProcessor接口的类,并将该类配置到Spring容器中。代码展示如下: - public class CustomBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
- public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
- System.out.println(beanFactory.getClass().getSimpleName());
- }
- }
-
- <bean id="customBeanFactoryPostProcessor" class="com.cjm.spring.CustomBeanFactoryPostProcessor"/>
Spring内置的实现类: 1、PropertyPlaceholderConfigurer类 用于读取Java属性文件中的属性,然后插入到BeanFactory的定义中。 - <bean id="propertyPlaceholderConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
- <property name="locations">
- <list>
- <value>jdbc.properties</value>
- </list>
- </property>
- </bean>
-
- <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>
PropertyPlaceholderConfigurer的另一种精简配置方式(context命名空间): - <context:property-placeholder location="classpath:jdbc.properties, classpath:mails.properties"/>
Java属性文件内容: jdbc.driverClassName=oracle.jdbc.driver.OracleDriver jdbc.url=jdbc:oracle:thin:@localhost:1521:orcl jdbc.username=qycd jdbc.password=qycd 除了可以读取Java属性文件中的属性外,还可以读取系统属性和系统环境变量的值。 读取系统环境变量的值:${JAVA_HOME} 读取系统属性的值:${user.dir}
2、PropertyOverrideConfigurer类 用于读取Java属性文件中的属性,并覆盖XML配置文件中的定义,即PropertyOverrideConfigurer允许XML配置文件中有默认的配置信息。 Java属性文件的格式: beanName.property=value beanName是属性占位符企图覆盖的bean名,property是企图覆盖的数姓名。 - <bean id="propertyOverrideConfigurer" class="org.springframework.beans.factory.config.PropertyOverrideConfigurer">
- <property name="locations">
- <list>
- <value>jdbc.properties</value>
- </list>
- </property>
- </bean>
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- <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
- <property name="driverClassName" value="11"/>
- <property name="url" value="22"/>
- <property name="username" value="33"/>
- <property name="password" value="44"/>
- </bean>
Java属性文件内容: dataSource.driverClassName=oracle.jdbc.driver.OracleDriver dataSource.url=jdbc:oracle:thin:@localhost:1521:orcl dataSource.username=qycd dataSource.password=qycd 九、ResourceBundleMessageSource类 提供国际化支持,bean的名字必须为messageSource。此处,必须存在一个名为jdbc的属性文件。 - <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
- <property name="basenames">
- <list>
- <value>jdbc</value>
- </list>
- </property>
- </bean>
jdbc.properties属性文件的内容: - welcome={0}, welcome to guangzhou!
- AbstractApplicationContext ctx = new FileSystemXmlApplicationContext("applicationContext.xml");
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- ctx.getMessage("welcome", new String[]{"张三"}, "", Locale.CHINA);
十、FactorBean接口 用于创建特定的对象,对象的类型由getObject方法的返回值决定。 - public class MappingFactoryBean implements FactoryBean {
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- public Object getObject() throws Exception {
- List<String> configs = ApplicationContext.getContext().getApplication().getMappingConfigs();
- return configs.toArray(new String[configs.size()]);
- }
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- public Class<?> getObjectType() {
- return String[].class;
- }
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- public boolean isSingleton() {
- return true;
- }
- }
- public class MappingAutowiring implements BeanPostProcessor {
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- private String[] mappingResources;
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- public String[] getMappingResources() {
- return mappingResources;
- }
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- public void setMappingResources(String[] mappingResources) {
- this.mappingResources = mappingResources;
- }
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- public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
- if (bean instanceof LocalSessionFactoryBean) {
- ((LocalSessionFactoryBean) bean).setMappingResources(mappingResources);
- }
- return bean;
- }
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- public Object postProcessAfterInitialization(Object bean, String beanName)
- throws BeansException {
- return bean;
- }
- }
- <bean id="mappingAutowiring" class="com.achievo.framework.server.core.deploy.MappingAutowiring">
- <property name="mappingResources" ref="mappingResources" />
- </bean>
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- <bean id="mappingResources" class="com.achievo.framework.server.core.deploy.MappingFactoryBean" />
十一、CustomEditorConfigurer类 可以读取实现java.beans.PropertyEditor接口的类,将字符串转为指定的类型。更方便的可以使用PropertyEditorSupport。PropertyEditorSupport实现PropertyEditor接口,必须重新定义setAsText。 - public class Hello {
- private String message;
- private User user;
-
- public String getMessage() {
- return message;
- }
- public void setMessage(String message) {
- this.message = message;
- }
- public User getUser() {
- return user;
- }
- public void setUser(User user) {
- this.user = user;
- }
- }
自定义属性编辑器继承PropertyEditorSupport类,重写setAsText方法。 - public class UserEditor extends PropertyEditorSupport{
- @Override
- public void setAsText(String text) throws IllegalArgumentException {
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- String[] arr = text.split(",");
- Integer age = new Integer(arr[1]);
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- User user = new User();
- user.setName(arr[0]);
- user.setAge(age);
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- setValue(user);
- }
- }
bean配置 - <bean id="configBean"
- class="org.springframework.beans.factory.config.CustomEditorConfigurer">
- <property name="customEditors">
- <map>
-
- <entry key="User">
- <bean id="userEditor" class="UserEditor"/>
- </entry>
- </map>
- </property>
- </bean>
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- <bean id="hello" class="Hello">
- <property name="message" value="hello" />
- <property name="user" value="chenjumin,20"/>
- </bean>
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