JDK6.0发布有段时间了,新的JDK也有不少新的特性,我去网上搜集了一下,列在下面和大家一起学习.
1.Desktop和SystemTray. 在JDK6中 ,AWT新增加了两个类:Desktop和SystemTray,前者可以用来打开系统默认浏览器浏览指定的URL,打开系统默认邮件客户端给指定的邮箱发邮件,用默认应用程序打开或编辑文件(比如,用记事本打开以txt为后缀名的文件),用系统默认的打印机打印文档;后者可以用来在系统托盘区创建一个托盘程序。
我随便找了几张图,在Tray里面都是空的,没有图,可能是图太大,有xdjm知道希望告诉我
import java.awt.AWTException; import java.awt.Desktop; import java.awt.Image; import java.awt.MenuItem; import java.awt.PopupMenu; import java.awt.SystemTray; import java.awt.Toolkit; import java.awt.TrayIcon; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import java.io.IOException; import java.net.URI; import java.net.URISyntaxException; public class DesktopTrayTest { private static Desktop desktop; private static SystemTray st; private static PopupMenu pm; public static void main( String[] args ) { if ( Desktop.isDesktopSupported() ) { desktop = Desktop.getDesktop(); } if ( SystemTray.isSupported() ) { st = SystemTray.getSystemTray(); Image image = Toolkit.getDefaultToolkit().createImage( " http://www.51ppt.com.cn/Article/Uploadphotos/200604/20064147333288.png " ); createPopupMenu(); TrayIcon ti = new TrayIcon( image, " Demo " , pm ); try { st.add( ti ); } catch ( AWTException awte ) { awte.printStackTrace(); } } } public static void sendMail( String mail ) { if ( desktop != null && desktop.isSupported( Desktop.Action.MAIL ) ) { try { desktop.mail( new URI( mail ) ); } catch (IOException e) { e.printStackTrace(); } catch (URISyntaxException e) { e.printStackTrace(); } } } public static void openBrowser( String url ) { if ( desktop != null && desktop.isSupported( Desktop.Action.BROWSE )) { try { desktop.browse( new URI( url ) ); } catch (IOException e) { e.printStackTrace(); } catch (URISyntaxException e) { e.printStackTrace(); } } } public static void edit() { if ( desktop != null && desktop.isSupported( Desktop.Action.EDIT ) ) { File file = new File( " test.txt " ); try { if ( file.exists() == false ) { file.createNewFile(); } desktop.edit( file ); } catch ( IOException ioe ) { ioe.printStackTrace(); } } } public static void createPopupMenu() { pm = new PopupMenu(); MenuItem ob = new MenuItem( " Open url " ); ob.addActionListener( new ActionListener() { public void actionPerformed( ActionEvent ae ) { openBrowser( " http://blog.csdn.net/xumingming64398966 " ); } } ); MenuItem sm = new MenuItem( " Send Mail " ); sm.addActionListener( new ActionListener() { public void actionPerformed( ActionEvent ae ) { sendMail( " [email protected] " ); } } ); MenuItem ed = new MenuItem( " Edit " ); ed.addActionListener( new ActionListener() { public void actionPerformed( ActionEvent ae ) { edit(); } } ); MenuItem ex = new MenuItem( " Exit " ); ex.addActionListener( new ActionListener() { public void actionPerformed( ActionEvent ae ) { System.exit( 0 ); } } ); pm.add( ob ); pm.add( sm ); pm.add( ed ); pm.addSeparator(); pm.add( ex ); } }
2.Console. JDK6中提供了java.io.Console类专用来访问基于字符的控制台设备. 你的程序如果要与Windows下的cmd或者Linux下的Terminal交互,就可以用Console类代劳. 但我们不总是能得到可用的Console, 一个JVM是否有可用的Console依赖于底层平台和JVM如何被调用. 如果JVM是在交互式命令行(比如Windows的cmd)中启动的,并且输入输出没有重定向到另外的地方,那么就可以得到一个可用的Console实例. 下面代码演示了Console类的用法:
import java.io.Console; public class ConsoleTest { public static void main( String[] args ) { Console console = System.console(); if ( console != null ) { String user = new String( console.readLine( " Enter User: " , new Object[ 0 ] ) ); String pwd = new String( console.readPassword( " Enter Password: " , new Object[ 0 ] )); console.printf( " User name is:%s " , new Object[] {user} ); console.printf( " Password is:%s " , new Object[] {pwd} ); } else { System.out.println( " No Console! " ); } } }
你如果是在一个IDE中如eclipse, netbeans中运行你将得到:
No Console!
因为只有在命令行中才能得到Console对象。
3.Compiler API. 现在我们可以用JDK6 的Compiler API(JSR 199)去动态编译Java源文件,Compiler API结合反射功能就可以实现动态的产生Java代码并编译执行这些代码,有点动态语言的特征。这个特性对于某些需要用到动态编译的应用程序相当有用,比如JSP Web Server,当我们手动修改JSP后,是不希望需要重启Web Server才可以看到效果的,这时候我们就可以用Compiler API来实现动态编译JSP文件,当然,现在的JSP Web Server也是支持JSP热部署的,现在的JSP Web Server通过在运行期间通过Runtime.exec或ProcessBuilder来调用javac来编译代码,这种方式需要我们产生另一个进程去做编译工作,不够优雅而且容易使代码依赖与特定的操作系统;Compiler API通过一套易用的标准的API提供了更加丰富的方式去做动态编译,而且是跨平台的。 下面代码演示了Compiler API的使用:
import java.io.BufferedWriter; import java.io.FileWriter; import java.io.IOException; import java.util.Iterator; import javax.tools.JavaCompiler; import javax.tools.JavaFileObject; import javax.tools.StandardJavaFileManager; import javax.tools.ToolProvider; public class CompilerAPITest { private final static String srcFileName = "Test.java"; private final static String classFileName = "Test.class"; private final static String className = "Test"; public static void main( String[] args ) { JavaCompiler compiler = ToolProvider.getSystemJavaCompiler(); if( compiler == null ) { System.err.println( "Compiler is null!" ); return; } StandardJavaFileManager fileManager = compiler.getStandardFileManager( null, null, null ); generateJavaClass(); Iterable < ? extends JavaFileObject> sourceFiles = fileManager.getJavaFileObjects( new String[]{ srcFileName } ); compiler.getTask( null, fileManager, null, null, null, sourceFiles ).call(); try { fileManager.close(); Class.forName( className ).newInstance(); } catch (IOException e) { e.printStackTrace(); } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (ClassNotFoundException e) { e.printStackTrace(); } } public static void generateJavaClass() { try { FileWriter rw = new FileWriter( srcFileName ); BufferedWriter bw = new BufferedWriter( rw ); bw.write( "public class " + className + " {" ); bw.newLine(); bw.write( "public " + className + "() {"); bw.newLine(); bw.write( "System.out.println( 'you are in the constructor of Class Test' );" ); bw.write( "}" ); bw.newLine(); bw.write( "}" ); bw.flush(); bw.close(); } catch (IOException e) { e.printStackTrace(); } } }
我在运行这个例子的时候发现ToolProvider.getSystemJavaCompiler得到的是NULL,后来上网一查,原来是一个Bug!链接如下:
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6477844
Closed, not reproducible
那为什么我一直在reproduce阿?
4.Http Server API. JDK6提供了一个简单的Http Server API,据此我们可以构建自己的嵌入式Http Server,它支持Http和Https协议,提供了HTTP1.1的部分实现,没有被实现的那部分可以通过扩展已有的Http Server API来实现,程序员必须自己实现HttpHandler接口,HttpServer会调用HttpHandler实现类的回调方法来处理客户端请求,在这里,我们把一个Http请求和它的响应称为一个交换,包装成HttpExchange类,HttpServer负责将HttpExchange传给 HttpHandler实现类的回调方法.下面代码演示了怎样创建自己的Http Server .
import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.net.InetSocketAddress; import com.sun.net.httpserver.HttpExchange; import com.sun.net.httpserver.HttpHandler; import com.sun.net.httpserver.HttpServer; public class HttpServerAPITest { private static int count = 0; public static void main( String[] args ) { try { HttpServer hs = HttpServer.create( new InetSocketAddress( 8888 ), 0 ); hs.createContext( "/", new MyHandler() ); hs.createContext( "/java", new MyHandler() ); hs.setExecutor( null ); hs.start(); System.out.println( "---begin---" ); System.out.println( "Listening on " + hs.getAddress() ); } catch( IOException ioe ) { ioe.printStackTrace(); } } static class MyHandler implements HttpHandler { public void handle( HttpExchange he ) throws IOException { System.out.println( "Request " + count++ ); System.out.println( he.getHttpContext().getPath() ); InputStream is = he.getRequestBody(); String response = "Happy Spring Festerval"; he.sendResponseHeaders( 200, response.length() ); OutputStream os = he.getResponseBody(); os.write( response.getBytes() ); os.close(); } } }
5.对脚本语言的支持如: ruby, groovy, javascript.
代码如下:
import java.io.FileReader; import javax.script.Invocable; import javax.script.ScriptEngine; import javax.script.ScriptEngineManager; public class ScriptTest { public static void main( String[] args ) { ScriptEngineManager manager = new ScriptEngineManager(); ScriptEngine engine = manager.getEngineByName( "ECMAScript" ); try { engine.eval( new FileReader( "C:\test.js" ) ); Invocable invocableEngine = (Invocable)engine; Object ret = invocableEngine.invokeFunction( "test", null ); System.out.println( "The result is :" + (Double)ret ); } catch( Exception e ) { e.printStackTrace(); } } }
test.js如下:
function test(){ return Math.round( 11.2 ); }
6.插入式注解处理API(Pluggable Annotation Processing API),插入式注解处理API(JSR 269)提供一套标准API来处理Annotations.JSR 269用Annotation Processor在编译期间而不是运行期间处理Annotation, Annotation Processor相当于编译器的一个插件,所以称为插入式注解处理.如果Annotation Processor处理Annotation时(执行process方法)产生了新的Java代码,编译器会再调用一次Annotation Processor,如果第二次处理还有新代码产生,就会接着调用Annotation Processor,直到没有新代码产生为止.每执行一次process()方法被称为一个"round",这样整个Annotation processing过程可以看作是一个round的序列.
举个例子:们想建立一套基于Annotation的单元测试框架(如TestNG),在测试类里面用Annotation来标识测试期间需要执行的测试方法,如下所示:
@TestMethod public void testCheckName(){ //do something here }
这时我们就可以用JSR 269提供的API来处理测试类,根据Annotation提取出需要执行的测试方法.
再举个例子: 下面我用代码演示如何来用JSR 269提供的API来处理Annotations和读取Java源文件的元数据(metadata)
import java.util.List; import java.util.Map; import java.util.Set; import javax.annotation.processing.AbstractProcessor; import javax.annotation.processing.RoundEnvironment; import javax.annotation.processing.SupportedAnnotationTypes; import javax.annotation.processing.SupportedSourceVersion; import javax.lang.model.SourceVersion; import javax.lang.model.element.AnnotationMirror; import javax.lang.model.element.AnnotationValue; import javax.lang.model.element.Element; import javax.lang.model.element.ExecutableElement; import javax.lang.model.element.TypeElement; import javax.lang.model.util.ElementFilter; import javax.tools.Diagnostic.Kind; @SupportedAnnotationTypes( "ToBeTested" ) @SupportedSourceVersion( SourceVersion.RELEASE_6 ) public class MyAnnotationProcessor extends AbstractProcessor { private void note( String msg ) { processingEnv.getMessager().printMessage( Kind.NOTE, msg ); } public boolean process( Set< ? extends TypeElement > annotations, RoundEnvironment roundEnv ) { for( TypeElement te : annotations ) { note( "annotation: " + te.toString() ); } Set< ? extends Element > elements = roundEnv.getRootElements(); for( Element e : elements ) { List< ? extends Element > enclosedElems = e.getEnclosedElements(); List< ? extends ExecutableElement > ees = ElementFilter.methodsIn( enclosedElems ); for( ExecutableElement ee : ees ) { note( "Executable Element Name: " + ee.getSimpleName() ); List< ? extends AnnotationMirror > as = ee.getAnnotationMirrors(); note( " as: " + as ); for( AnnotationMirror am : as ){ Map< ? extends ExecutableElement, ? extends AnnotationValue > map = am.getElementValues(); Set< ? extends ExecutableElement > ks = map.keySet(); for( ExecutableElement k : ks ) { AnnotationValue av = map.get( k ); note("----"+ee.getSimpleName()+"."+k.getSimpleName()+"="+av.getValue()); } } } } return false; } } public class Testing { @ToBeTested(group="A") public void m1(){ } @ToBeTested(group="B",owner="QQ") public void m2(){ } } import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; @Retention( RetentionPolicy.RUNTIME ) @Target( ElementType.METHOD ) public @interface ToBeTested { String owner() default "Chinajash"; String group(); }
效果如下:
[img]
http://bbs.sjtu.edu.cn/file/job/116919470662560.BMP
[/img]
7.StAX. StAX是The Streaming API for XML的缩写,是继DOM(Document Object Model)和SAX(Simple API for XML)之后的又一种处理xml的api,一种利用拉模式解析(pull-parsing)XML文档的API.StAX通过提供一种基于事件迭代器(Iterator)的API让程序员去控制xml文档解析过程,程序遍历这个事件迭代器去处理每一个解析事件,解析事件可以看做是程序拉出来的,也就是程序促使解析器产生一个解析事件然后处理该事件,之后又促使解析器产生下一个解析事件,如此循环直到碰到文档结束符;SAX也是基于事件处理xml文档,但却是用推模式解析,解析器解析完整个xml文档后,才产生解析事件,然后推给程序去处理这些事件;DOM采用的方式是将整个xml文档映射到一颗内存树,这样就可以很容易地得到父节点和子结点以及兄弟节点的数据,但如果文档很大,将会严重影响性能。
下面是个例子:
import java.io.FileNotFoundException; import java.io.FileOutputStream; import javax.xml.namespace.QName; import javax.xml.stream.XMLEventReader; import javax.xml.stream.XMLInputFactory; import javax.xml.stream.XMLOutputFactory; import javax.xml.stream.XMLStreamException; import javax.xml.stream.XMLStreamWriter; import javax.xml.stream.events.StartElement; import javax.xml.stream.events.XMLEvent; public class StaxTest { public static void main( String[] arg ) throws XMLStreamException, FileNotFoundException { readXMLByStAX(); writeXMLByStAX(); } public static void readXMLByStAX() throws XMLStreamException, FileNotFoundException { XMLInputFactory factory = XMLInputFactory.newInstance(); XMLEventReader reader = factory.createXMLEventReader( StaxTest.class.getResourceAsStream( "test.xml" ) ); XMLEvent event; StringBuffer parsingResult = new StringBuffer(); while( reader.hasNext() ) { event = reader.nextEvent(); if( event.isStartElement() ) { StartElement se = event.asStartElement(); parsingResult.append( "<" ); parsingResult.append( se.getName() ); if( se.getName().getLocalPart().equals( "catalog" ) ) { parsingResult.append( "id="" ); parsingResult.append( se.getAttributeByName( new QName( "id" ) ).getValue()); parsingResult.append( """ ) ; } parsingResult.append( ">" ); } else if( event.isCharacters() ) { parsingResult.append( event.asCharacters().getData() ); } else if( event.isEndElement() ) { parsingResult.append( "" ); } } System.out.println( parsingResult ); } public static void writeXMLByStAX() throws XMLStreamException, FileNotFoundException { XMLOutputFactory factory = XMLOutputFactory.newInstance(); XMLStreamWriter writer = factory.createXMLStreamWriter( new FileOutputStream( "output.xml" ) ); writer.writeStartDocument(); writer.writeCharacters( " " ); writer.writeComment( "testing comment" ); writer.writeCharacters( " " ); writer.writeStartElement( "catalogs" ); writer.writeNamespace( "myNS", "http://blog.csdn.net/Chinajash" ); writer.writeAttribute( "owner", "sina" ); writer.writeCharacters( " " ); writer.writeStartElement("http://blog.csdn.net/Chinajash", "catalog"); writer.writeAttribute("id","007"); writer.writeCharacters("Apparel"); // 写入catalog元素的结束标签 writer.writeEndElement(); // 写入catalogs元素的结束标签 writer.writeEndElement(); // 结束 XML 文档 writer.writeEndDocument(); writer.close(); } } test.xml:Book Video
8. Web Service. 由于Web服务日趋流行,利用Web服务的功能性的API特征正从最新的Java EE版本中向Java SE 6平台迁移。换言之,针对Web服务不需另外加入额外的工具,在Java EE和Java SE平台拥有相同的API。野马将大把不同的Web服务相关的API加到标准的工具柜中:以JSR 181针对Java 平台的Web服务元数据,通过JSR 224的基于XML 的Web服务Java API(JAX-WS);针对Java的带有附件的SOAP API(SAAJ)作为JSR 67 。与三个Web服务API相关的包新增到Java SE 6.0里:JAX-WS API 放置到javax.xml.ws包; SAAJ类在javax.xml.soap 包; Web服务的元数据类放置在javax.jws包里。 下面是一个简单的例子, 下面的代码是要作为web service发布的类。
package hello; import javax.jws.WebService; import javax.xml.ws.Endpoint; @WebService public class CircleFunctions { public double getArea( int radius ) { return Math.PI * radius * radius; } public double getCircumference( int radius ) { return Math.PI * radius * 2; } public static void main( String[] args ) { Endpoint.publish( "http://localhost:8888/WebServiceExample/circlefunctions", new CircleFunctions()); } }
处理的方法如下:
javac -d ./ CircleFunctions.java
wsgen hello.CircleFunctions
java hello.CircleFunctions
然后在浏览器中输入如下url,你将得到一个xml页面:
http: //localhost:8888/WebServiceExample/circlefunctions?WSDL
参考网页:
1.Desktop和SystemTray. http://dev.yesky.com/411/3019911.shtml
2.Console. http://dev.yesky.com/133/3032133.shtml
3.Compiler API. http://developer.51cto.com/art/200701/37359.htm
4.HttpServer API. http://www.testage.net/QA/Dev/200701/1396.htm
5. 对脚本语言的支持http://blog.edwardro.com/read.php?167
6. 插入式注解处理API. http://ourconan.com.cn/article.php?itemid-2113-type-blog.html
7.StAX. http://ourconan.com.cn/article.php?itemid-2111-type-blog.html
8.Web Service. http://www.360doc.com/showWeb/0/0/298124.aspx
9.JDK1.5的Annotation
http://lzqdiy.bokee.com/viewdiary.14724866.html