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( "64398966@qq.com" );
}
});
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 = "<font color='blue'>Happy Spring Festerval</font>";
he.sendResponseHeaders( 200, response.length() );
OutputStream os = he.getResponseBody();
os.write( response.getBytes() );
os.close();
}
}
}
效果如图:
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:
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( "</" );
parsingResult.append( event.asEndElement().getName() );
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:
<?xml version="1.0" encoding="UTF-8"?>
<catalogs>
<catalog id="001">Book</catalog>
<catalog id="002">Video</catalog>
</catalogs>
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