📄 index.xtp
字号:
<document> <header> <product>resin</product> <title>Hessian Serialization</title> <description> <p>Hessian 2.0 provides cross-language binary object serializationwith efficiencies better than java.io serialization. The compactionencodings added to Hessian 2.0 have improved an already-popularcross-platform binary web services protocol. With these changes, Hessian2.0 now directly competes with java.io serialization in efficiency.</p> </description> <type>tutorial</type> <tutorial-startpage>serialize</tutorial-startpage> </header> <body> <summary/><s1 title="Files in this tutorial"><deftable><tr> <td><viewfile-link file="WEB-INF/classes/example/HessianSerializeServlet.java"/></td> <td>Serialization Servlet</td></tr><tr> <td><viewfile-link file="WEB-INF/classes/example/Car.java"/></td> <td>Serialized class</td></tr><tr> <td><viewfile-link file="WEB-INF/classes/example/Color.java"/></td> <td>Enumeration for the car color</td></tr><tr> <td><viewfile-link file="WEB-INF/classes/example/Model.java"/></td> <td>Enumeration for the car model</td></tr></deftable></s1><s1 title="Overview"><p>In this simple example, we'll use Hessian 2.0 to serializethree Car objects to a byte array. The serialized data could be saved ina persistent store, or sent as a message in a SOA or JMS application.Because Hessian 2.0 is cross-language, the message could be deserialized by a.NET or even a PHP application.</p><p>The efficiency of Hessian 2.0 is about twice that of java.ioserialization. This is a tiny example, of course, but does show that you cansend compact, cross-language messages without having to use bloatedXML solutions like SOAP.</p><deftable><tr> <td>Hessian 2.0</td> <td>139 bytes</td></tr><tr> <td>java.io</td> <td>287 bytes</td></tr><tr> <td>Hessian 2.0 with Deflation</td> <td>164 bytes</td></tr></deftable></s1><s1 title="Model"><p>The example's model is a Car object with three fields: year, model, andcolor. The model and color are enumeration types.</p><example title="Car.java">package example;public class Car { private int year; private Model model; private Color color;}</example><example title="Car.java">package example;public enum Model { CIVIC, EDSEL, MODEL_T,}</example><example title="Color.java">package example;public enum Model { BLACK, GREEN, BLUE,}</example></s1><s1 title="Hessian Serialization"><p>The Hessian serialization API resemblesjava.io <code>ObjectOutputStream</code> serialization. The general stepsare to create a <code>Hessian2Output</code>around any <code>OutputStream</code> and write data to the stream.In this example, we've encapsulated the object in a Hessian 2.0 messageusing <code>startMessage</code> and <code>completeMessage</code> toshow how you would create a message for an SOA or JMS application.</p><example title="Serialization">ByteArrayOutputStream bos = new ByteArrayOutputStream();Hessian2Output out = new Hessian2Output(bos);out.startMessage(); out.writeInt(2);Car car1 = new Car(Model.EDSEL, Color.GREEN, 1954);out.writeObject(car1);Car car2 = new Car(Model.MODEL_T, Color.BLACK, 1937);out.writeObject(car2);out.completeMessage();out.close();byte []data = bos.toByteArray();</example><p>The deserialization is the same as serialization.Create an <code>Hessian2Input</code> around any <code>InputStream</code>and read data from the stream.</p><example title="Deserialization">ByteArrayInputStream bin = new ByteArrayInputStream(data);Hessian2Input in = new Hessian2Input(bin);in.startMessage();ArrayList list = new ArrayList();int length = in.readInt();for (int i = 0; i < length; i++) { list.add(in.readObject());}in.completeMessage();in.close();bin.close();</example></s1><s1 title="Hessian Compression"><p>The <a href="http://caucho.com/resin-3.1/doc/hessian-2.0-spec.xtp">Hessian2.0 draft specification</a> has added support for envelopes around Hessianmessages. These envelopes can provide additional capabilities likecompression, encryption, and message signatures. The envelope can alsobe used to attach routing and reliability information to a message. Sinceenvelopes are nestable, each envelope can be simple and provide powerfulcapabilities when combined. For example, a secure messaging systemmight compress, encrypt and then securely sign a message.</p><p>The API for using envelopes is <code>wrap()</code> for writing a messageand <code>unwrap()</code> for reading a message. The applicationserialization code itself is identical, since the envelope just creates a<code>Hessian2Input</code> or <code>Hessian2Output</code> wrapper aroundthe original stream.</p><example title="Deflation">Deflation envelope = new Deflation();ByteArrayOutputStream bos = new ByteArrayOutputStream();Hessian2Output out = new Hessian2Output(bos);out = out.wrap(out);out.startMessage();Car car1 = new Car(Model.EDSEL, Color.GREEN, 1954);out.writeObject(car1);out.completeMessage();out.close();byte []data = bos.toByteArray();</example><example title="Inflation">Deflation envelope = new Deflation();ByteArrayInputStream bin = new ByteArrayInputStream(data);Hessian2Input in = new Hessian2Input(bin);in = envelope.unwrap(in);in.startMessage();Object value = in.readObject();in.completeMessage();</example></s1> </body></document>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -