Struts2 异常处理
Struts2 异常处理机制
任何程序设计语言都是有异常处理机制，Struts2通过使用声明式异常机制处理异常。
在Struts2中主要有两种异常映射方式：
1：局部异常处理 (action)
2：全局异常处理 (package)
异常主要是通过Struts2的拦截器机制处理异常和异常处理机制来处理异常，
Struts2中大部分都是使用拦截器实现。interceptor
输出异常信息
使用Struts2的标签来输出异常信息：
﹤s:property value="exception.message"/﹥：输出异常对象本身。
﹤s:property value="exceptionStack"/﹥： 输出异常堆栈信息。
实例
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
struts2的声明式异常处理：
<a href="/exep_holder.action">异常处理</a>
</body>
</html>
struts.xml
<package name="global-default" namespace="/" extends="struts-default"> <!-- 全局异常处理 --> <global-results> <result name="error">/error.jsp</result> </global-results> <global-exception-mappings> <exception-mapping result="error" exception="java.lang.ArithmeticException"></exception-mapping> </global-exception-mappings> </package> <package name="exeception_holder" namespace="/" extends="global-default"> <action name="exep_holder" class="com.struts2.action.ExceptionHolderController" method="holder"> <!-- 局部异常处理 <result name="error">/error.jsp</result> <exception-mapping result="error" exception="java.lang.ArithmeticException"></exception-mapping> --> </action> </package>
ExceptionHolderController.java
package com.struts2.action;
import com.opensymphony.xwork2.ActionSupport;
public class ExceptionHolderController extends ActionSupport {
public String holder() throws Exception {
String str_error="";
int i= 100/0;
if(i>0) {
str_error="错误显示";
}
else{
str_error="正确显示";
}
this.addFieldError("error_message", str_error);
return ERROR;
}
}
error.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">
<title>My JSP 'error.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<s:property value="exception.message"/><br/>
<s:property value="exceptionStack"/><br/>
<s:property value="error_message"/><br/>
<s:debug></s:debug>
</body>
</html>