比XML更好用的Java-Annotation课件

JavaTWO

專業技術大會

JavaAnnotation

李日貴(jini)AboutMejini@JWorld.TW(jakarta99)SoftLeaderTech.Corp.Presidentsince2002FocusondevinJavaenterprise

applicationsforInsurances,BankingandBetting.ResearchingandSharingJavaOpensourcesMyGoogle+(http://gplus.to/jakarta99)SinglenowAgendaIntroductionServlet3.0EJB3.1WebServicesCDIOpensourcesJavassist/ASM@Annotation

Course1

Introduction

What’sannotationBeginwith“@”AnInterfaceSetValues@Annotation@Annotation(“someValue”)@Annotation(var1=“someA”,var2=“someB”)@Annotation(value={“Apple”,“Banana”,“Cherry”})RetentionPolicy@AnnotationRuntimeDefaultvalueStereotypeFindtheclassescontain@AnnotationInitializethemaswhatyouwantTogeneratethecodesorxmlandetc..@Target(ElementType)@AnnoTarget(TYPE)publicclassTheTarget{ @AnnoTarget(FIELD)

privateStringglobalMsg; @AnnoTarget(CONSTRUCTOR)

publicTheTarget(){

//Thisisaconstructor

}

@AnnoTarget(METHOD)

publicvoidsomeMethod(@AnnoTarget(PARAMETER)

StringmyParam){ //Thisisamethod }}@Annotation

Course2

Servlet3.0

Servlet2.5packagejavatwo.annotation;publicclassCatServletextendsHttpServlet{ publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse) throwsServletException,IOException{

//dosomething }}web.xml<web-app> <servlet> <servlet-name>CatServlet</servlet-name> <servlet-class>javatwo.annotation.CatServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>CatServlet</servlet-name> <url-pattern>/cat</url-pattern> </servlet-mapping></web-app>Servlet3.0packagejavatwo.annotation;@WebServlet(“/cat”)publicclassCatServletextendsHttpServlet{ publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{

//dosomething }}@WebServlet(name="catServlet",urlPatterns="/cat",

initParams={@WebInitParam(name="name",value="bobo")})Servlet3.0Noweb.xmlneeded@WebServlet -DefineaServlet@WebFilter

-DefineaFilter@WebListener -DefineaListener@WebInitParam -Defineinitparameter@MultipartConfig-DefineuploadpropertiesCanuseweb.xmltooverridevaluesthatspecifiedbytheAnnotations.FileUploadinServlet3.0@WebServlet(“/upload”)@MultipartConfig(location=“c:\\tmp”)publicclassFileUploadServletextendsHttpServlet{ publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)throwsServletException,IOException{ Collection<Part>parts=request.getParts(); for(Partpart:parts){

part.write(“upload.txt”);//savetoc:\tmp\upload.txt }}setAsyncinServlet3.0@WebServlet(name=“AsyncServlet”,urlPatterns=“/async”,asyncSupported=“true”)publicclassAsyncServletextendsHttpServlet{ publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse){

AsyncContext

aCtx=request.startAsync(request,response);

ServletContextsc=request.getServletContext(); ((Queue<AsyncContext>)sc.getAttribute(“slowQueue")).add(aCtx); }}@WebListenerpublicclassSlowQueueListenerimplementsServletContextListener{ publicvoidcontextInitialized(ServletContextEvent

sce){…}}@Annotation

Course3

EJB3.1

EJB2.xpublicinterfaceCalculatorLocalextendsEJBLocalObject{..}publicinterfaceCalculatorLocalHomeextendsEJBLocalHome{..}publicclassCalculatorBeanimplementsSessionBean{..}ejb-jar.xml<ejb-jar> <enterprise-beans> <session> <ejb-name>calculator</ejb-name> <local-home>CalculatorLocalHome</local-home> <local>CalculatorLocal</local> <ejb-class>CalculatorBean</ejb-class> <session-type>Stateless</session-type> <transaction-type>Container</transaction-type> </session> </enterprise-beans></ejb-jar>EJB3.0@LocalpublicinterfaceCalculatorLocal

extendsEJBLocalObject

{..}publicinterfaceCalculatorHomeextendsEJBHome{..}@StatelesspublicclassCalculatorBeanimplementsCalculatorLocal{..}ejb-jar.xmlEJB3.1(LocalBean)@LocalpublicinterfaceCalculatorLocalextendsEJBLocalObject{..}publicinterfaceCalculatorHomeextendsEJBHome{..}@StatelesspublicclassCalculatorBean

implementsCalculatorLocal{..}ejb-jar.xmlSingletonSessionBean@Singleton@ConcurrencyManagement(ConcurrencyManagementType.CONTAINER)publicclassSingletonBean{ privateint

clickCount=0;

@Lock(LockType.WRITE) publicint

getClickCount(){ returnclickCount++; }}//Thread-Safe,TransactionalScheduleTimer@SingletonpublicclassTransFileBean{

@Schedule(minute=“0”,hour=“4”,dayOfMonth=“Last”) publicvoidtrans(){ //dotransfer }}@Annotation

Course4

WebServicesWebServices“Big”WebServicesSOAPJAX-WSjavax.jws.*RESTful

WebServicesRESTJAX-RSjavax.ws.rs.*SOAPWebServiceimportjavax.jws.WebMethod;importjavax.jws.WebService;@WebService(serviceName=“helloService”)publicclassHello{

@WebMethod publicStringsayHello(Stringname){ return“Hello“+name; }}RESTful

WebServiceimportjavax.ws.rs.GET;importjavax.ws.rs.Path;importjavax.ws.rs.PathParam;importjavax.ws.rs.Produces;importjavax.ws.rs.core.MediaType;@Path("/helloREST/{name}")publicclassHelloREST{

@GET @Produces(MediaType.TEXT_PLAIN) publicStringgetHello(@PathParam("name")Stringname){ return"Hello*"+name+"*fromJAX-RS"; } }@Annotation

Course5

CDIResourceInjectionJEE5@WebServlet(“/product”)publicProductServletextendsHttpServlet{

@Inject privateProductBean

productBean; ..}@StatelesspublicclassProductBean{ ..}AmbiguousInject@Qualifierpublic@interfaceCarPolicyNo{}@Qualifierpublic@interfaceFirePolicyNo{}@CarPolicyNoGeneratorpublicclassCarPolicyNoGeneratorimplementsPolicyNoGenerator{..}@FirePolicyNoGeneratorpublicclassFirePolicyNoGeneratorimplementsPolicyNoGenerator{..}publicclassFireService{

@Inject @FirePolicyNoGenerator privatePolicyNoGenerator

policyNoGenerator;}@ProducespublicclassDatabaseProducer{

@Produces@PersistenceContext(unitName=“ds1”)

@FireDatabase privateEntityManager

em;}publicclassFireService{

@Inject

@FireDatabase privateEntityManager

em;}@Annotation

Course6

OpensourcesjUnit3.ximportjunit.framework.Assert;importjunit.framework.TestCase;publicclassCalculateServiceTest3extendsTestCase{ publicvoidsetUp()throwsException{} publicvoidtestSum(){

intactual=newCalculateService().sum(3,5);

Assert.assertEquals(8,actual); } publicvoidtearDown()throwsException{}}jUnit4.xpublicclassCalculateServiceTest4extendsTestCase{ @BeforeClass publicstaticvoidsetUpBeforeClass()throwsException{}

@Before publicvoidbeforeTest()throwsException{}

@Test publicvoidtheSum(){ Assert.assertEquals(8,newCalculateService().sum(3,5)); }

@After publicvoidafterTest()throwsException{}

@AfterClass publicstaticvoidtearDownAfterClass()throwsException{}}Spring2.5<beans> <beanid=“newsDao”class=“javatwo.annotation.spring.NewsDao”/> <beanid=“newsService”class=“javatwo.annotation.spring.NewsService”> <propertyname=“newsDao”> <refbean=“newsDao”/> </property> </bean></beans>@ServicepublicclassNewsService{

@Autowired privateNewsDao

newsDao;}

Spring3.0@NamedpublicclassNewsService{

@Inject privateNewsDao

newsDao;}Spring3.0@ConfigurationpublicclassAppConfig{ private@Value(“#{sysprop.dbURL}”)StringdbURL; private@Value(“#{sysprop.username}”)Stringusername; private@Value(“#{sysprop.password}”)Stringpassword;

@Bean publicDataSource

dataSource(){ returnnewDriverManagerDataSource(dbURL,username,password); }}MVCinSpring3.0@Controller@RequestMapping(“/news”)publicclassNewsController{

@RequestMaaping(value=“{id}”, method=RequestMethod.GET)

publicModelAndView

getById(@PathVariable(“id”)Longid){ return… }}@Annotation

Course7

Javassist/ASMReflectionClassmyClass=MyClass.class;Method[]myMethods=myClass.getMethods();for(Method

myMethod:myMethods){

Annotation[]annotations=myMethod.getAnnotations(); for(Annotation

annotation:annotations){ if(annotationinstanceof

MyAnno){

MyAnno

myAnno=(MyAnno)annotation; //dosomething } }}ScaninClassLoaderproject(basedonjavassist)URL[]urls=ClasspathUrlFinder.findClassPaths();AnnotationDBdb=newAnnotationDB();db.scanArchives(urls);Map<String,Set<String>>annoIndex=db.getAnnotationIndex();Set<String>aClassNames=annoIndex.get(“java