spring 学习2-Spring Configuration in detail
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2023-12-30 21:04:10
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1.Bean Life-Cycle Management
<bean id="simpleBean1" class="com.apress.prospring3.ch5.lifecycle.SimpleBean" init-method="init" />
<bean id="destructiveBean" class="com.apress.prospring3.ch5.lifecycle.DestructiveBean" destroy-method="destroy"/>
public class SimpleBeanWithInterface implements InitializingBean{
private static final String DEFAULT_NAME = "Luke Skywalker";
private String name = null;
private int age = Integer.MIN_VALUE;
public void setName(String name) {
this.name = name;
}
public void setAge(int age) {
this.age = age;
}
public void myInit() {
System.out.println("My Init");
}
public void afterPropertiesSet() throws Exception {
System.out.println("Initializing bean");
if (name == null) {
System.out.println("Using default name");
name = DEFAULT_NAME;
}
public class DestructiveBeanWithInterface implements InitializingBean,
DisposableBean{
private InputStream is = null;
public String filePath = null;
public void afterPropertiesSet() throws Exception {
System.out.println("Initializing Bean");
if (filePath == null) {
throw new IllegalArgumentException(
"You must specify the filePath property of " + DestructiveBean.class);
}
is = new FileInputStream(filePath);
}
public void destroy() {
System.out.println("Destroying Bean");
if (is != null) {
try {
is.close();
is = null;
} catch (IOException ex) {
System.err.println("WARN: An IOException occured"
+ " trying to close the InputStream");
}
}
}
public void setFilePath(String filePath) {
this.filePath = filePath;
}
public class SimpleBeanWithJSR250 {
// Codes omitted
@PostConstruct
public void init() throws Exception {
// Rest of codes omitted
}
}
public class DestructiveBeanWithJSR250 {
private InputStream is = null;
public String filePath = null;
@PostConstruct
public void afterPropertiesSet() throws Exception {
System.out.println("Initializing Bean");
if (filePath == null) {
throw new IllegalArgumentException(
"You must specify the filePath property of " + DestructiveBean.class);
}
is = new FileInputStream(filePath);
}
@PreDestroy
public void destroy() {
System.out.println("Destroying Bean");
if (is != null) {
try {
is.close();
is = null;
} catch (IOException ex) {
System.err.println("WARN: An IOException occured"
+ " trying to close the InputStream");
}
}
}
public void setFilePath(String filePath) {
this.filePath = filePath;
}
2.Making Your Beans “Spring Aware”
public class ShutdownHookBean implements ApplicationContextAware {
private ApplicationContext ctx;
public void setApplicationContext(ApplicationContext ctx)
throws BeansException {
if (ctx instanceof GenericApplicationContext) {
((GenericApplicationContext) ctx).registerShutdownHook();
}
}
}
<bean id="destructiveBean" class="com.apress.prospring3.ch5.lifecycle.DestructiveBeanWithInterface"> <property name="filePath"> <value>d:/temp/test.txt</value> </property> </bean> <bean id="shutdownHook" class="com.apress.prospring3.ch5.interaction.ShutdownHookBean"/>
3.Using ApplicationContext and MessageSource
public static void main(String[] args) {
GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();
ctx.load("classpath:appContext/messageSource.xml");
ctx.refresh();
Locale english = Locale.ENGLISH;
Locale czech = new Locale("cs", "CZ");
System.out.println(ctx.getMessage("msg", null, english));
System.out.println(ctx.getMessage("msg", null, czech));
System.out.println(ctx.getMessage("nameMsg", new Object[] { "Clarence",
"Ho" }, english));
}
<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource"> <property name="basenames"> <list> <value>buttons</value> <value>labels</value> </list> </property> </bean>
4.Using Application Events
public class MessageEvent extends ApplicationEvent {
private String msg;
public MessageEvent(Object source, String msg) {
super(source);
this.msg = msg;
}
public String getMessage() {
return msg;
}
}
public class MessageEventListener implements ApplicationListener<MessageEvent> {
public void onApplicationEvent(MessageEvent event) {
MessageEvent msgEvt = (MessageEvent) event;
System.out.println("Received: " + msgEvt.getMessage());
}
}
public class Publisher implements ApplicationContextAware {
private ApplicationContext ctx;
public static void main(String[] args) {
ApplicationContext ctx = new ClassPathXmlApplicationContext(
"classpath:events/events.xml");
Publisher pub = (Publisher) ctx.getBean("publisher");
pub.publish("Hello World!");
pub.publish("The quick brown fox jumped over the lazy dog");
}
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.ctx = applicationContext;
}
public void publish(String message) {
ctx.publishEvent(new MessageEvent(this, message));
}
}
<bean id="publisher" class="com.apress.prospring3.ch5.event.Publisher"/> <bean id="messageEventListener" class="com.apress.prospring3.ch5.event.MessageEventListener"/>
5.Accessing Resources
public static void main(String[] args) throws Exception{
ApplicationContext ctx = new ClassPathXmlApplicationContext(
"classpath:events/events.xml");
Resource res1 = ctx.getResource("file:///d:/temp/test.txt");
displayInfo(res1);
Resource res2 = ctx.getResource("classpath:test.txt");
displayInfo(res2);
Resource res3 = ctx.getResource("http://www.google.co.uk");
displayInfo(res3);
}
private static void displayInfo(Resource res) throws Exception{
System.out.println(res.getClass());
System.out.println(res.getURL().getContent());
System.out.println("");
//getFile(), getInputStream(), or getURL()
}
6. Java Configuration
@Configuration
public class AppConfig {
// XML:
// <bean id="messageProvider"
class="com.apress.prospring3.ch5.javaconfig.ConfigurableMessageProvider"/>
@Bean
public MessageProvider messageProvider() {
return new ConfigurableMessageProvider();
}
// XML:
// <bean id="messageRenderer"
class="com.apress.prospring3.ch5.javaconfig.StandardOutMessageRenderer"
// p:messageProvider-ref="messageProvider"/>
@Bean
public MessageRenderer messageRenderer() {
MessageRenderer renderer = new StandardOutMessageRenderer();
// Setter injection
renderer.setMessageProvider(messageProvider());
return renderer;
}
@Configuration
@Import(OtherConfig.class)
// XML: <import resource="classpath:events/events.xml")
@ImportResource(value="classpath:events/events.xml")
// XML: <context:property-placeholder location="classpath:message.properties"/>
@PropertySource(value="classpath:message.properties")
// XML: <context:component-scan base-package="com.apress.prospring3.ch5.context"/>
@ComponentScan(basePackages={"com.apress.prospring3.ch5.context"})
@EnableTransactionManagement public class AppConfig {
@Autowired
Environment env;
// XML:
// <bean id="messageProvider"
class="com.apress.prospring3.ch5.javaconfig.ConfigurableMessageProvider"/>
@Bean
@Lazy(value=true) //XML <bean .... lazy-init="true"/>
public MessageProvider messageProvider() {
// Constructor injection
return new ConfigurableMessageProvider(env.getProperty("message"));
}
// XML:
// <bean id="messageRenderer"
class="com.apress.prospring3.ch5.javaconfig.StandardOutMessageRenderer"
// p:messageProvider-ref="messageProvider"/>
@Bean(name="messageRenderer")
@Scope(value="prototype") // XML: <bean ... scope="prototype"/>
@DependsOn(value="messageProvider") // XML: <bean ... depends-on="messageProvider"/>
public MessageRenderer messageRenderer() {
MessageRenderer renderer = new StandardOutMessageRenderer();
// Setter injection
renderer.setMessageProvider(messageProvider());
return renderer;
}
}
7.ConfigurableEnvironment env = ctx.getEnvironment();
MutablePropertySources propertySources = env.getPropertySources();
8.JSR-330
@Named("messageRenderer")
@Singleton
public class StandardOutMessageRenderer implements MessageRenderer {
@Inject
@Named("messageProvider")
private MessageProvider messageProvider = null;
public void render() {
if (messageProvider == null) {
throw new RuntimeException(
"You must set the property messageProvider of class:"
+ StandardOutMessageRenderer.class.getName());
}
System.out.println(messageProvider.getMessage());
}
public void setMessageProvider(MessageProvider provider) {
this.messageProvider = provider;
}
public MessageProvider getMessageProvider() {
return this.messageProvider;
}
}
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