東方未名

JDK6.0發布有段時間了，新的JDK也有不少新的特性，我去網上搜集了一下，列在下面和大家一起學習．
１．Desktop和SystemTray. 在JDK6中 ,AWT新增加了兩個類:Desktop和SystemTray,前者可以用來打開系統默認瀏覽器瀏覽指定的URL,打開系統默認郵件客戶端給指定的郵箱發郵件,用默認應用程序打開或編輯文件(比如,用記事本打開以txt為后綴名的文件),用系統默認的打印機打印文檔;后者可以用來在系統托盤區創建一個托盤程序。

我隨便找了幾張圖，在Tray里面都是空的，沒有圖,可能是圖太大，有xdjm知道希望告訴我

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類專用來訪問基于字符的控制臺設備. 你的程序如果要與Windows下的cmd或者Linux下的Terminal交互,就可以用Console類代勞. 但我們不總是能得到可用的Console, 一個JVM是否有可用的Console依賴于底層平臺和JVM如何被調用. 如果JVM是在交互式命令行(比如Windows的cmd)中啟動的,并且輸入輸出沒有重定向到另外的地方,那么就可以得到一個可用的Console實例. 下面代碼演示了Console類的用法:

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! " ?);
????????}
????}
}

３．Compiler API. 現在我們可以用JDK6 的Compiler API(JSR 199)去動態編譯Java源文件，Compiler API結合反射功能就可以實現動態的產生Java代碼并編譯執行這些代碼，有點動態語言的特征。這個特性對于某些需要用到動態編譯的應用程序相當有用，比如JSP Web Server，當我們手動修改JSP后，是不希望需要重啟Web Server才可以看到效果的，這時候我們就可以用Compiler API來實現動態編譯JSP文件，當然，現在的JSP Web Server也是支持JSP熱部署的，現在的JSP Web Server通過在運行期間通過Runtime.exec或ProcessBuilder來調用javac來編譯代碼，這種方式需要我們產生另一個進程去做編譯工作，不夠優雅而且容易使代碼依賴與特定的操作系統；Compiler API通過一套易用的標準的API提供了更加豐富的方式去做動態編譯,而且是跨平臺的。 下面代碼演示了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();
????????}
????}
}

我在運行這個例子的時候發現ToolProvider.getSystemJavaCompiler得到的是NULL,后來上網一查，原來是一個Bug!鏈接如下：
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6477844

Closed, not reproducible
那為什么我一直在reproduce阿？?

4.Http Server API. JDK6提供了一個簡單的Http Server API,據此我們可以構建自己的嵌入式Http Server,它支持Http和Https協議,提供了HTTP1.1的部分實現，沒有被實現的那部分可以通過擴展已有的Http Server API來實現,程序員必須自己實現HttpHandler接口,HttpServer會調用HttpHandler實現類的回調方法來處理客戶端請求,在這里,我們把一個Http請求和它的響應稱為一個交換,包裝成HttpExchange類,HttpServer負責將HttpExchange傳給 HttpHandler實現類的回調方法.下面代碼演示了怎樣創建自己的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();
????????}
????}
}

5.對腳本語言的支持如: ruby, groovy, javascript.

代碼如下:

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.插入式注解處理API(Pluggable Annotation Processing API)，插入式注解處理API(JSR 269)提供一套標準API來處理Annotations.JSR 269用Annotation Processor在編譯期間而不是運行期間處理Annotation, Annotation Processor相當于編譯器的一個插件,所以稱為插入式注解處理.如果Annotation Processor處理Annotation時(執行process方法)產生了新的Java代碼,編譯器會再調用一次Annotation Processor,如果第二次處理還有新代碼產生,就會接著調用Annotation Processor,直到沒有新代碼產生為止.每執行一次process()方法被稱為一個"round",這樣整個Annotation processing過程可以看作是一個round的序列.
舉個例子：們想建立一套基于Annotation的單元測試框架(如TestNG),在測試類里面用Annotation來標識測試期間需要執行的測試方法,如下所示:

@TestMethod
?public?void?testCheckName(){
???????//do?something?here
?}

再舉個例子: 下面我用代碼演示如何來用JSR 269提供的API來處理Annotations和讀取Java源文件的元數據(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的縮寫，是繼DOM(Document Object Model)和SAX(Simple API for XML)之后的又一種處理xml的api,一種利用拉模式解析(pull-parsing)XML文檔的API.StAX通過提供一種基于事件迭代器(Iterator)的API讓程序員去控制xml文檔解析過程,程序遍歷這個事件迭代器去處理每一個解析事件，解析事件可以看做是程序拉出來的，也就是程序促使解析器產生一個解析事件然后處理該事件，之后又促使解析器產生下一個解析事件，如此循環直到碰到文檔結束符；SAX也是基于事件處理xml文檔，但卻是用推模式解析，解析器解析完整個xml文檔后，才產生解析事件，然后推給程序去處理這些事件；DOM采用的方式是將整個xml文檔映射到一顆內存樹，這樣就可以很容易地得到父節點和子結點以及兄弟節點的數據，但如果文檔很大，將會嚴重影響性能。

下面是個例子：

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");
????????//?寫入catalog元素的結束標簽
????????writer.writeEndElement();
????????//?寫入catalogs元素的結束標簽
????????writer.writeEndElement();
????????//?結束?XML?文檔
????????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服務日趨流行，利用Web服務的功能性的API特征正從最新的Java EE版本中向Java SE 6平臺遷移。換言之，針對Web服務不需另外加入額外的工具，在Java EE和Java SE平臺擁有相同的API。野馬將大把不同的Web服務相關的API加到標準的工具柜中：以JSR 181針對Java 平臺的Web服務元數據，通過JSR 224的基于XML 的Web服務Java API（JAX-WS）；針對Java的帶有附件的SOAP API（SAAJ）作為JSR 67 。與三個Web服務API相關的包新增到Java SE 6.0里：JAX－WS API 放置到javax.xml.ws包； SAAJ類在javax.xml.soap 包； Web服務的元數據類放置在javax.jws包里。 下面是一個簡單的例子，　下面的代碼是要作為web service發布的類。

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());
????}
}

處理的方法如下：
javac -d ./ CircleFunctions.java
wsgen hello.CircleFunctions
java hello.CircleFunctions
然后在瀏覽器中輸入如下url,你將得到一個xml頁面：
http:?//localhost:8888/WebServiceExample/circlefunctions?WSDL?

參考網頁：
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. 對腳本語言的支持http://blog.edwardro.com/read.php?167
6. 插入式注解處理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?