Spring是一个完整的J2EE框架和解决方案,完整并且模块化,你可以用的他的全部也可以只用他的一部分特性,Spring 包含 IoC, AOP, 事务处理,ORM, 也包括一个简单的MVC框架.
用Spring,自我感觉,可以使你的代码至少节约30%,它的很多template很不错的,比如简单封装后的jdbctemplate,jmstemplate等。
ioc用后就会爱不释手,它让你的代码风格完全改观。以前我要产生个对象,绝大多数时候只回想到new一个对象,而用spring的ioc,beanfactory,只需要配置一个xml文件即可。这种方式实现了松偶合,对单元测试非常有利。
还有它的aop,也是很不错的,
用spring的感觉,正如它的名字一样:如沐春风.
关于spring中的jms,最近一个项目用到,刚好研究了一下,在这里做一个整理备份.在此感谢同事Eric的帮助.
spring把jms进行了简单的封装,用它的JmsTemplate可以很方便的发送和接收消息,并且资源的管理都由template来管理了.
1:在web.xml文件中配置一个spring用的上下文:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/jmsconfig.xml
</param-value>
</context-param>
jmsconfig.xml用来装配jms,内容如下:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING/DTD BEAN/EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id="jmsConnectionFactory"
class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>jms/Ntelagent/RequestQCF</value>
</property>
</bean>
<bean id="destination"
class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>jms/Ntelagent/RequestQ</value>
</property>
</bean>
<bean id="jmsConnectionFactoryForReceive"
class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>jms/Ntelagent/ResponseQCF</value>
</property>
</bean>
<bean id="destinationForReceive"
class="org.springframework.jndi.JndiObjectFactoryBean">
<property name="jndiName">
<value>jms/Ntelagent/ResponseQ</value>
</property>
</bean>


<bean id="jmsTemplate" class="org.springframework.jms.core.JmsTemplate102">
<property name="connectionFactory">
<ref bean="jmsConnectionFactory"/>
</property>
<property name="defaultDestination">
<ref bean="destination"/>
</property>
<property name="messageConverter">
<ref bean="jmsTrxConverter"/>
</property>
<property name="receiveTimeout">
<value>1</value>
</property>
</bean>
<bean id="jmsTemplateForReceive" class="org.springframework.jms.core.JmsTemplate102">
<property name="connectionFactory">
<ref bean="jmsConnectionFactoryForReceive"/>
</property>
<property name="defaultDestination">
<ref bean="destinationForReceive"/>
</property>
<property name="messageConverter">
<ref bean="jmsTrxConverter"/>
</property>
<property name="receiveTimeout">
<value>1</value>
</property>
</bean>
<bean id="jmsTrxConverter" class="co.transport.jms.JmsTransactionConverter">
<property name="rspQueue">
<ref bean="destinationForReceive"/>
</property>
</bean>
<bean id="jmsRequestTransport" class="co.transport.jms.JmsRequestTransport">
<property name="jmsTemplate">
<ref bean="jmsTemplate"/>
</property>
<property name="jmsTemplateForReceive">
<ref bean="jmsTemplateForReceive"/>
</property>
</bean>

</beans>

其中:
jmsConnectionFactory为jms连接工厂,属性jndiName的value为server服务配置的jndi名称.
destination为消息队列,属性jndiName为消息队列的jndi名称.
jmsTemplate为配置spring消息模版:采用JmsTemplate102(如果你的JMS实现符合JMS规范1.1版,则应该使用JmsTemplate),其中的messageConverter属性配置了一个消息转换器,因为通常消息在发送前和接收后都需要进行一个前置和后置处理,转换器便进行这个工作。
由于我的sendQueue很receiveRueue是不同的queue,所以我配置了两个jmsTemplate:
jmsTemplateForReceive负责接收消息,jmsTemplate负责发发送消息.
发送消息的代码很简单:
jmsTemplate.convertAndSend(request);
接收消息也很简单:
Object obj = jmsTemplate.receiveAndConvert();
如果需要用一个过滤器接收特定的消息,则:
Object obj = this.jmsTemplateForReceive.receiveSelectedAndConvert(this.messageSelector);
发送和接收消息的class如下:



public class JmsRequestTransport implements RequestTransport ...{
private JmsTemplate jmsTemplate;
private JmsTemplate jmsTemplateForReceive;
private String messageSelector;
private String destinationName;

public void setJmsTemplate(JmsTemplate template)...{
this.jmsTemplate = template;
}


public void request(Object request) ...{
jmsTemplate.convertAndSend(request);
}

public Object receive() ...{
System.out.println("in JmsRequestTransport: destinationName = " + this.jmsTemplateForReceive.getDefaultDestinationName());
System.out.println("in JmsRequestTransport: messageSelector = " + messageSelector);
Object obj = this.jmsTemplateForReceive.receiveSelectedAndConvert(this.messageSelector);
return obj;
}


public String getMessageSelector() ...{
return messageSelector;
}


public void setMessageSelector(String string) ...{
messageSelector = string;
}


public String getDestinationName() ...{
return destinationName;
}


public void setDestinationName(String string) ...{
destinationName = string;
}


public JmsTemplate getJmsTemplateForReceive() ...{
return jmsTemplateForReceive;
}


public void setJmsTemplateForReceive(JmsTemplate template) ...{
jmsTemplateForReceive = template;
}

}


要实现一个消息转换器,只需要实现MessageConverter接口,MessageConverter很简单,它只有两个方法需要实现:
public Object fromMessage(Message msg){}
public Message toMessage(Object obj, Session session) throws JMSException{}
fromMessage为接收消息后,对消息进行的转换(通常是把一个message转化为一个Object对象)
toMessage为发送消息前需要的转化(通常为把一个Object转化为一个message对象)
我的JmsTransactionConverter转换器如下:

public class JmsTransactionConverter implements MessageConverter ...{
private Queue rspQueue;


public JmsTransactionConverter()...{}

public Object fromMessage(Message msg)...{
MessageBean msgBean = new MessageBean();
TextMessage massage = (TextMessage)msg;


try ...{
String str = massage.getText();
msgBean.setHead("HeadTest");
msgBean.setOutput(str);
msgBean.setStatus("success");

} catch (JMSException e) ...{
// TODO Auto-generated catch block
msgBean = null;
e.printStackTrace();
}

finally ...{
return msgBean;
}
}

public Message toMessage(Object obj, Session session) throws JMSException...{

String s = (String)obj;

TextMessage message = session.createTextMessage(s);
message.setStringProperty("mytype","java");
return message;
}


public Queue getRspQueue() ...{
return rspQueue;
}


public void setRspQueue(Queue queue) ...{
rspQueue = queue;
}

}


其中:MessageBean是一个简单javabean:

public class MessageBean ...{
private String head;
private String output;
private String status;


public String getHead() ...{
return head;
}


public String getOutput() ...{
return output;
}


public String getStatus() ...{
return status;
}



public void setHead(String string) ...{
head = string;
}


public void setOutput(String string) ...{
output = string;
}


public void setStatus(String string) ...{
status = string;
}

}


然后就可以用两个servlet来测试发送和接收消息:
发送消息:

public class JMSTestServlet extends HttpServlet ...{


/** *//**
* @see javax.servlet.http.HttpServlet#void (javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException

...{
doGet(req, resp);
}
public void doGet(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException...{
ServletOutputStream out = resp.getOutputStream();

try ...{
ServletContext servletContext = this.getServletContext();
WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
JmsRequestTransport transport = (JmsRequestTransport)wac.getBean("jmsRequestTransport");
System.out.println("in JMSTestServlet.doGet:begin send message");
String messageToSend = req.getParameter("message");
if(messageToSend == null)

...{
messageToSend = "Default Message";
}
transport.request(messageToSend);
String s = "in JMSTestServlet.doGet:after send message and message is: " + messageToSend;
out.println("<HTML><BODY>");
out.println(s);
out.println("<br><input type=button name=back value=back onclick=history.back()>");
out.println("<br><a href=receiveServlet>receive</a>");
out.println("</HTML></BODY>");

} catch(Exception e) ...{
out.println("<HTML><BODY>");
out.println(e.toString());
out.println("</HTML></BODY>");
}
}

接收消息:

public class receiveServlet extends HttpServlet ...{


/** *//**
* @see javax.servlet.http.HttpServlet#void (javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException

...{
doGet(req, resp);
}

public void doGet(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException ...{
ServletOutputStream out = resp.getOutputStream();
String selector = req.getParameter("selector");
String distination = req.getParameter("distination");

try ...{
String s = "nothing";
ServletContext servletContext = this.getServletContext();
WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(servletContext);
JmsRequestTransport transport = (JmsRequestTransport)wac.getBean("jmsRequestTransport");

System.out.println("selector = " + selector);
System.out.println("distination = " + distination);
transport.setDestinationName(distination);
transport.setMessageSelector(selector);
Object obj = transport.receive();

if(obj != null) ...{
MessageBean msgBean = (MessageBean)obj;
//System.out.println("in receiveServlet:");
s = "receive the message is: " + msgBean.getHead() + "," +
msgBean.getOutput() + ", " +
msgBean.getStatus();

} else ...{
s = "there is no message where " + selector;
}
out.println("<HTML><BODY>");
out.println(s);
out.println("<br>selector is :" + selector);
out.println("<br>distination is :" + distination);
out.println("<br><a href=jsp/sendMessage.jsp>sendMessage</a>");
out.println("</HTML></BODY>");

} catch(Exception e) ...{
out.println("<HTML><BODY>");
out.println("<br>selector is :" + selector);
out.println("<br>distination is :" + distination);
out.println("<br>" + e.toString());
out.println("</HTML></BODY>");
}

}

}
