了解Hessian

Hessian是远程调用的一种技术，和WebService类似，但不同的是较WebService而言，它更轻量级，更简单，更快速。关于Hessian更详细全面的介绍可以查看http://hessian.caucho.com/。下面可以花十五分钟的时间，学会怎么简单的使用Hessian。

使用Hessian

在Eclipse建立一个Maven webapp项目：

右键项目添加Hessian的依赖：

Maven随后会去*仓库下载Hessian相关的jar包。

添加一个提供Hessian服务的接口：

   1:  /**

   2:   * @ClassName: HessianService

   3:   * @Description: Hessian服务接口

   4:   * @author liping.action@gmail.com

   5:   * @date 2014-1-3 下午10:41:26

   6:   * 

   7:   */

   8:  public interface HessianService {

   9:      public String sayHello(String name);

  10:  }

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

以及现实类：

   1:  public class HessianServiceImpl implements HessianService {

   2:      /*

   3:       * (non-Javadoc)

   4:       * 

   5:       * @see

   6:       * com.cnblogs.leefreeman.hessian.service.HessianService#sayHello(java.lang

   7:       * .String)

   8:       */

   9:      @Override

  10:      public String sayHello(String name) {

  11:          // TODO Auto-generated method stub

  12:          return "hello " + name;

  13:      }

  14:  }

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

最后在web.xml中增加hessian相应的配置：

   1:  <servlet>

   2:         <servlet-name>service</servlet-name>

   3:         <servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>

   4:         <load-on-startup>1</load-on-startup>

   5:         <init-param>

   6:             <param-name>service-class</param-name>

   7:             <param-value>com.cnblogs.leefreeman.hessian.service.impl.HessianServiceImpl</param-value>

   8:         </init-param>

   9:      </servlet>

  10:      <servlet-mapping>

  11:         <servlet-name>service</servlet-name>

  12:         <url-pattern>/service</url-pattern>

  13:      </servlet-mapping>

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }

现在Hessian服务端就算完成，是不是觉得很简单。启动项目：

打开该页面说明Hessian服务端启动正常。接口下来编写客户端测试用例:

   1:  public class HessianServiceTest {

   2:      private final static String SERVICE_URL = "http://localhost:8080/hessian-project/service";

   3:   

   4:      @Test

   5:      public void testSayHello() {

   6:          HessianProxyFactory proxyFactory = new HessianProxyFactory();

   7:          try {

   8:              HessianService hessianService = (HessianService) proxyFactory

   9:                      .create(HessianService.class, SERVICE_URL);

  10:              System.out.println(hessianService.sayHello("liping"));

  11:          } catch (MalformedURLException e) {

  12:              e.printStackTrace();

  13:          }

  14:      }

  15:  }

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }结果：

一个简单的Hession应用就完成了，相比搭建Webservice项目，要简单得多。