一个简单的例子学习hessian服务：服务端为
Java，客户端为C#。
先要准备好C#和Java的第三方类库：http://hessian.caucho.com/
Hssiancharp.dll
hessian-4.0.37.jar
Hessian服务端（java）
打开eclipse创建一个Dynamic Web Project，将hessian-4.0.37.jar放到lib下，大概如图所示：
创建一个通信接口IHello：
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package hessian.test.server;
import java.util.ArrayList;
public interface IHello {
String sayHello(String msg);
void sayHello2(int bean);
void print(String msg);
HelloBean getData(HelloBean bean);
ArrayList<HelloBean> getBeanList();
ComplexData getComplexData();
}
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IHello接口的一个实现：HelloImpl.java
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package hessian.test.server;
import java.util.ArrayList;
public class HelloImpl implements IHello{
public String sayHello(String msg){
return "Hello " + msg;
}
public void sayHello2(int bean){
System.out.println("Hello " + bean);
}
public void print(String msg){
System.out.println(msg);
}
public HelloBean getData(HelloBean bean){
HelloBean result = new HelloBean();
result.setName("lu xiaoxun a new name");
result.setAge(26);
System.out.print(bean.getName());
return result;
}
public ArrayList<HelloBean> getBeanList(){
ArrayList<HelloBean> beans = new ArrayList<HelloBean>();
HelloBean b1 = new HelloBean();
b1.setName("lu1");
b1.setAge(26);
beans.add(b1);
HelloBean b2 = new HelloBean();
b2.setName("lu2");
b2.setAge(27);
beans.add(b2);
return beans;
}
public ComplexData getComplexData(){
ComplexData data = new ComplexData();
ArrayList<HelloBean> beans = getBeanList();
data.setData(beans, beans.size());
return data;
}
}
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定义用来进行数据传输的类，两个类都必须实现Serializable接口：
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HelloBean.java
package hessian.test.server;
import java.io.Serializable;
public class HelloBean implements Serializable {
private static final long serialVersionUID = 570423789882653763L;
private String name;
private int age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge(){
return age;
}
public void setAge(int age){
this.age = age;
}
}
ComplexData.java
package hessian.test.server;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
public class ComplexData implements Serializable{
private static final long serialVersionUID = 1L;
private ArrayList<HelloBean> helloBeans;
//private Map<String, HelloBean> helloBeanMap;
private int number;
public int getNumber(){
return number;
}
public ArrayList<HelloBean> getHelloBeans(){
return helloBeans;
}
public void setData(ArrayList<HelloBean> beans, int num){
this.number = num;
this.helloBeans = beans;
// helloBeanMap = new HashMap<String, HelloBean>();
// for (HelloBean helloBean : beans) {
// if(!helloBeanMap.containsKey(helloBean.getName()))
// {
// helloBeanMap.put(helloBean.getName(), helloBean);
// }
// }
}
}
web.xml内容：
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
id="WebApp_ID" version="3.0">
<display-name>hessian server</display-name>
<servlet>
<servlet-name>hessian</servlet-name>
<servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>
<init-param>
<param-name>service-class</param-name>
<param-value>hessian.test.server.HelloImpl</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>hessian</servlet-name>
<url-pattern>/hessian</url-pattern>
</servlet-mapping>
</web-app>
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Hessian客户端（c#）
定义一个与服务端对应的IHello接口：IHello.cs
public interface IHello
{
String sayHello(String msg);
void sayHello2(int bean);
void print(String msg);
HelloBean getData(HelloBean bean);
HelloBean[] getBeanList();
ComplexData getComplexData();
}
定义与服务器端一致的的通信数据类：
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HelloBean.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace hessian.test.server
{
public class HelloBean
{
public String Name
{
set { name = value; }
get { return name; }
}
private String name; //类型和名称需要和服务器端一致
public int Age
{
set { age = value; }
get { return age; }
}
private int age; //类型和名称需要和服务器端一致
public override String ToString()
{
return "Name: "+ name + " Age: " + age;
}
}
}
ComplexData.cs：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace hessian.test.server
{
public class ComplexData
{
private HelloBean[] helloBeans;
//private Dictionary<String, HelloBean> helloBeanMap;
private int number;
public int GetNumber()
{
return number;
}
public HelloBean[] GetBeans()
{
return helloBeans;
}
//public Dictionary<String, HelloBean> GetBeansDic()
//{
// return helloBeanMap;
//}
}
}
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在主项目中添加Hessiancsharp.dll引用。
测试代码：
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using hessiancsharp.client;
using hessian.test.server;
namespace HessianClientTest
{
class Program
{
static void Main(string[] args)
{
string url = @"http://localhost:8080/HessianServerTest/hessian";
CHessianProxyFactory factory = new CHessianProxyFactory();
IHello test = (IHello)factory.Create(typeof(IHello), url);
//Test function
Console.WriteLine(test.sayHello("lu")); //打印从服务器端获取的字符串
test.sayHello2(12); //在服务器端控制台打印 "Hello 12"
test.print("hessian"); //在服务器端控制台打印 "hessian"
//Test Object
HelloBean bean = new HelloBean();
//bean.setName("lu xiaoxun");
bean.Name = "luxiaoxun";
HelloBean result = test.getData(bean);
Console.WriteLine(result.Name);
Console.WriteLine(result.Age);
Console.WriteLine(result);
//Test Object Array
HelloBean[] beans = test.getBeanList();
if (beans != null)
{
foreach (HelloBean data in beans)
{
Console.WriteLine(data.ToString());
}
}
//Test complex data
ComplexData complexData = test.getComplexData();
if (complexData != null)
{
Console.WriteLine("Array number: " + complexData.GetNumber());
HelloBean[] comArray = complexData.GetBeans();
if (comArray != null)
{
foreach (HelloBean data in comArray)
{
Console.WriteLine(data.ToString());
}
}
//Dictionary<String, HelloBean> helloBeanMap = complexData.GetBeansDic();
//if (helloBeanMap != null)
//{
// foreach (String key in helloBeanMap.Keys)
// {
// Console.WriteLine(helloBeanMap[key].GetHelloBeanInfo());
// }
//}
}
Console.ReadKey();
}
}
}
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测试结果：
注意事项：
1、服务端和客户端用于数据传递的对象的命名空间要一致
IHello接口所在命名空间服务端和客户端可以不一致，但是IHello中用到的HelloBean和ComplexData在Java服务端和C#客户端中两个HelloBean类所在的命名空间要一致。
2、类的字段要一致
用于数据传输的类的字段名和字段类型要一致（修饰类型可以不一致）。
3、服务端的类要序列化
4、尽量使用基本的数据类型
从上面的测试可以看出，传递基本的类型没有问题，传递普通的类对象没有问题，传递ArrayList的时候也没有问题（C#客户端使用Array数组），但是传递HashMap字典的时候会有问题，C#这边使用Dictionary没法对应一致，可能是由于hash函数内部实现不一致导致的，具体原因不明。
最新内容请见作者的GitHub页：http://qaseven.github.io/
