struts2异常处理，global-results定义全局结果处理

<global-results>定义全局结果处理

一般发生异常之后 结果返回errHandler

因为errHandler是由<global-exception-mappings>关联到Exception这个类了然后处理结果

 <result name="errHandler" type="chain">

然后它就根据

<param name="actionName">errorProcessor</param>

找action

<action name="errorProcessor" class="cn.itcast.sh.error.ErrorProcess">
             <result>/error.jsp</result>
  </action>处理了 然后 返回到 error.jsp

在struts.xml中

 1 <?xml version="1.0" encoding="utf-8"?>
 2  <!DOCTYPE struts PUBLIC
 3  "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
 4 "http://struts.apache.org/dtds/struts-2.3.dtd">
 5 <struts>
 6 <constant name="struts.devMode" value="true" />
 7  <constant name="struts.enable.DynamicMethodInvocation" value="false"></constant>
 8  <!-- <constant name="struts.custom.i18n.resources" value="itcast"></constant> -->
 9 <package name="struts-global" namespace="/" extends="struts-default">
10 <global-results>
11 <result name="errHandler" type="chain">
12  <param name="actionName">errorProcessor</param>
13  </result>
14 </global-results>
15  <global-exception-mappings>
16  <exception-mapping result="errHandler" exception="java.lang.Exception">
17   </exception-mapping>
18  </global-exception-mappings>
19
20 <action name="errorProcessor" class="cn.itcast.sh.error.ErrorProcess">
21  <result>/error.jsp</result>
22   </action>
23 </package>

然后其他包都继承它 就默认使用了其中定义的 错误处理

然后实现 类

class="cn.itcast.sh.error.ErrorProcess"

package cn.itcast.sh.error;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class ErrorProcess extends ActionSupport {
 private Exception exception;

public Exception getException() {
       return exception;
 }

     public void setException(Exception exception) {
        this.exception = exception;
     }
    @Override
     public String execute()
    {
        ActionContext.getContext().getValueStack().push(this.exception.getMessage());　　　　　　//放到值栈顶
     return this.SUCCESS;
    }
}

例子

struts.xml配置

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE struts PUBLIC
 "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
 "http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<constant name="struts.devMode" value="true" />
  <constant name="struts.enable.DynamicMethodInvocation" value="false"></constant>
 <!-- <constant name="struts.custom.i18n.resources" value="itcast"></constant> -->
 <package name="struts-global" namespace="/" extends="struts-default">
 <global-results>
       <result name="errHandler" type="chain">
       <param name="actionName">errorProcessor</param>
      </result>
  </global-results>
   <global-exception-mappings>
  <exception-mapping result="errHandler" exception="java.lang.Exception">
      </exception-mapping>
  </global-exception-mappings>

  <action name="errorProcessor" class="cn.itcast.sh.error.ErrorProcess">
       <result>/error.jsp</result>
    </action>
 </package>
  <include file="struts-user.xml"></include>
</struts>

struts-user.xml中

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE struts PUBLIC
 "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="user" namespace="/" extends="struts-global">
 <action name="UserAction_*" method="{1}" class="cn.itcast.sh.action.UserAction">
     <result name="userList">/user/list.jsp</result>
  </action>
  </package>
 </struts>

然后 如果页面异常 都会转向 error.jsp中 显示

error.jsp可以进行错误显示

因为信息被放到栈顶了 所以可以取到

<s:property />