Java WebService学习笔记 - Axis进阶(二)

上一篇  Java WebService学习笔记 - Axis(一)

前一篇博文中简单介绍了Axis的使用方法,这篇将介绍一些Axis的一些高级特性

Axis中Handler的使用

Handler的作用和Struts中Filter类似,主要用于访问之前或之后做一些特别的处理。主要包括权限验证,授权,访问量统计等等。

下面一个简单的例子介绍一下具体的使用方法

访问量统计

关于访问量统计,最简单的方法是在类内部添加一个静态同步的字段,每次访问对其进行加1.但是在WebService的中可能你只有一个class文件,此时不能也不允许在类中进行修改;而且在类中添加方法的话侵入性比较高。

Handler处理类:CountHandler.java

package com.handler;

import org.apache.axis.AxisFault;
import org.apache.axis.MessageContext;
import org.apache.axis.handlers.BasicHandler; public class CountHandler extends BasicHandler
{ private static final long serialVersionUID = 6788857289474496020L; private long visitCount = 0L; @Override
public void invoke(MessageContext msgCtx) throws AxisFault
{ visitCount++; String className = (String)msgCtx.getProperty("className"); System.out.println("class:"+className+" current visit count :"+visitCount);
}
}

将CountHandler.java编译后放到服务器webapps/axis/WEB_INF/classes/com/handler/下。

在上一篇笔记中的<service>中添加Handler处理

	<service name="Answer" provider="java:RPC">
<span style="color:#ff0000;"><requestFlow>
<handler type="java:com.handler.CountHandler"/>
</requestFlow></span>
<parameter name="className" value="com.webservice.wsdd.Answer"/>
<parameter name="allowedMethods" value="*"/>
<beanMapping
qname="bean:Question"
xmlns:bean="BeanManger"
languageSpecificType="java:com.webservice.wsdd.Question"
/>
<span style="color:#ff0000;"><responseFlow>
<handler type="java:com.handler.CountHandler"/>
</responseFlow></span>
</service>

在访问之前或之后都是可以的,两次都会创建不同的对象进行处理,处理结果如下

class:com.webservice.wsdd.Answer current visit count :1
read question:先有鸡还是先有蛋!
class:com.webservice.wsdd.Answer current visit count :1
class:com.webservice.wsdd.Answer current visit count :2
read question:先有鸡还是先有蛋!
class:com.webservice.wsdd.Answer current visit count :2

验证

首先要弄清楚验证和授权的概念,以普通的web应用为例,当你点击一个菜单时

验证:验证用户名密码是否正确

授权:前提是验证通过.根据用户名查询出访问权限,跟菜单的访问权限进行逻辑处理,如果有权限访问,则授权访问,否则,拒绝访问

下面给出一个简单的验证的例子

VerifyHandler.java

package com.handler;

import org.apache.axis.AxisFault;
import org.apache.axis.MessageContext;
import org.apache.axis.handlers.BasicHandler;
import org.apache.axis.security.AuthenticatedUser;
import org.apache.axis.security.SecurityProvider;
import org.apache.axis.security.simple.SimpleSecurityProvider;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory; public class VerifiyHandler extends BasicHandler
{ private static final long serialVersionUID = 129414778283139001L; Log log = LogFactory.getLog(VerifiyHandler.class); @Override
public void invoke(MessageContext msgCtx) throws AxisFault
{
//1.获取安全机制
SecurityProvider provider = (SecurityProvider) msgCtx.getProperty("securityProvider"); if(provider == null)
{
provider = new SimpleSecurityProvider();
msgCtx.setProperty("securityProvider", provider);
} //2.验证访问,如果验证通过返回AuthenticatedUser对象,否则返回null
AuthenticatedUser user = provider.authenticate(msgCtx); if(user == null)
{
log.info("verify failed");
throw new AxisFault("username or password not correct,visit refused");
} //为后面授权进行准备...
msgCtx.setProperty("authenticatedUser", user);
msgCtx.setProperty("yourRole", "007"); log.info("verify success,username:"+user.getName());
}
}

和访问量统计处理步骤类似,配置文件如下

	<service name="Answer" provider="java:RPC">
<span style="color:#ff0000;"><requestFlow>
<handler type="java:com.handler.VerifiyHandler"/>
<handler type="java:com.handler.CountHandler"/>
</requestFlow>
</span> <parameter name="className" value="com.webservice.wsdd.Answer"/>
<parameter name="allowedMethods" value="*"/>
<beanMapping
qname="bean:Question"
xmlns:bean="BeanManger"
languageSpecificType="java:com.webservice.wsdd.Question"
/>
</service>

客户端访问时需要在原有的Call对象中设置username和password属性,属性值的映射内容可以在\webapps\axis\WEB-INF\users.lst中找到

			call.setUsername("user3");
call.setPassword("pass3");

运行结果如下

- verify failed
- verify success,username:user3
class:com.webservice.wsdd.Answer current visit count :1
read question:先有鸡还是先有蛋!

授权

AuthorizeHandler.java

package com.handler;

import java.util.StringTokenizer;

import org.apache.axis.AxisFault;
import org.apache.axis.MessageContext;
import org.apache.axis.handlers.BasicHandler;
import org.apache.axis.security.AuthenticatedUser;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory; public class AuthorizeHandler extends BasicHandler
{ private static final long serialVersionUID = -8124974403139594724L; Log log = LogFactory.getLog(this.getClass()); /**
*
*/
@Override
public void invoke(MessageContext msgContext) throws AxisFault { AuthenticatedUser user = (AuthenticatedUser) msgContext.getProperty("authenticatedUser"); if(user!=null)
{
String role = (String)msgContext.getProperty("yourRole"); String roles = (String)msgContext.getProperty("allowedRoles"); for (StringTokenizer t = new StringTokenizer(roles, ",");t.hasMoreTokens();) {
String allowedrole = t.nextToken();
if(allowedrole.contains(role))
{
log.info("authorize pass! welcome "+role);
return;
}
} log.info("sorry,you did not have the permitions!");
throw new AxisFault("sorry,you did not have the permitions!");
}
else
{
log.info("verify not pass,will not authorize!");
throw new AxisFault("verify not pass,will not authorize!");
}
} }

配置如下

<service name="Answer" provider="java:RPC">
<requestFlow>
<handler type="java:com.handler.VerifiyHandler"/>
<span style="color:#ff0000;"><handler type="java:com.handler.AuthorizeHandler"/></span>
<handler type="java:com.handler.CountHandler"/>
</requestFlow>
<parameter name="className" value="com.webservice.wsdd.Answer"/>
<parameter name="allowedMethods" value="*"/>
<span style="color:#ff0000;"><parameter name="allowedRoles" value="007,M"/></span>
<beanMapping
qname="bean:Question"
xmlns:bean="BeanManger"
languageSpecificType="java:com.webservice.wsdd.Question"
/>
</service>

运行结果如下

- verify success,username:user3
- authorize pass! welcome 007
class:com.webservice.wsdd.Answer current visit count :1
read question:先有鸡还是先有蛋!

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