struts2：异常处理

Struts2框架提供了自己的异常处理机制，只需要在struts.xml文件中配置异常处理即可，而不需要在Action方法中来捕捉异常。

传统方法

public String execute() throws Exception {
    try{
        //...
        
        return SUCCESS;
    }catch(SQLException ex) {  // SQL异常，返回ERROR
        ex.printStackTrace();
        return ERROR;
    }catch(InvalidInputException ex) { // Invalid异常，返回ERROR
        ex.printStackTrace();
        return ERROR;
    }catch(exception1 ex) {  // 自定义异常
        ex.printStackTrace();
        return "result1";
    }
}

Struts2方法

Strut2框架在struts.xml文件中配置异常通常有两种方式：全局异常配置和局部异常配置。分别通过<global-exception-mappings../>标签和<exception-mapping../>标签来配置。

下面模拟一个用户登录的场景，根据不同的输入，抛出不同的异常，然后将由struts2处理。

1. 创建登录页面（login.jsp）

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>异常测试页面</title>
</head>
<body>
<center>
<s:form action="user" theme="xhtml">
    <s:textfield label="Name(应该为admin)" name="name"/>
    <s:textfield label="Age(应该为18)" name="age" />
    <s:textfield label="Tel(应该为13800138000)" name="tel"/>
    <s:submit></s:submit>
</s:form>
</center>
</body>
</html>

2. 创建三个异常显示页面

loginException.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>自定义异常SecurityException</title>
</head>
<body>
<h4>
    <font color="red"><s:property value="exception.message"/></font><br/>
    <s:property value="exceptionStack"/>
</h4>
</body>
</html>

Exception.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>全局定义异常Excepition</title>
</head>
<body>
<h4>
    <font color="red"><s:property value="exception.message"/></font><br/>
    <s:property value="exceptionStack"/>
</h4>
</body>
</html>

SQLException.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="s" uri="/struts-tags"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>全局定义异常SQLException</title>
</head>
<body>
<h4>
    <font color="red"><s:property value="exception.message"/></font><br/>
    <s:property value="exceptionStack"/>
</h4>
</body>
</html>

3. 创建Action类

package com.clzhang.struts2.demo10;

import com.opensymphony.xwork2.ActionSupport;

public class UserAction extends ActionSupport {
    private static final long serialVersionUID = 1L;
    
    private String name;
    private String age;
    private String tel;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAge() {
        return age;
    }
    public void setAge(String age) {
        this.age = age;
    }
    public String getTel() {
        return tel;
    }
    public void setTel(String tel) {
        this.tel = tel;
    }

    @Override
    public String execute() throws Exception {
        if (!getName().equals("admin")) {
            throw new SecurityException("用户名错误，应该为admin！");

        } else if (!getAge().equals("18")) {
            throw new Exception("年龄错误，应该为18岁！");
        } else if (!getTel().equals("13800138000")) {
            throw new java.sql.SQLException();
        } else {
            return SUCCESS;
        }
    }
}

4. 创建自定义异常类

package com.clzhang.struts2.demo10;

public class SecurityException extends Exception {
    private static final long serialVersionUID = 1L;
    
    public SecurityException() {
        super();
    }

    private String message;
    public SecurityException(String message) {
        this.message = message;
    }

    public String getMessage() {
        return message;
    }
}

5. 修改struts.xml

加入如下代码：

        <global-results>
            <result name="Exception">/struts2/demo10/Exception.jsp</result>
            <result name="SQLException">/struts2/demo10/SQLException.jsp</result>
        </global-results>

        <global-exception-mappings>
            <exception-mapping exception="java.sql.SQLException" result="SQLException"/>
            <exception-mapping exception="java.lang.Exception" result="Exception"/>
        </global-exception-mappings>



        <action name="user" class="com.clzhang.struts2.demo10.UserAction">
            <exception-mapping exception="com.clzhang.struts2.demo10.SecurityException" result="login"/>
            <result name="login">/struts2/demo10/loginException.jsp </result>
            <result>/struts2/demo10/success.jsp</result>
        </action>

6. 启动Tomcat，测试

打开IE，输入地址：http://127.0.0.1:8080/st/struts2/demo10/login.jsp

结果如下：

直接提交（用户名不为admin），则抛出SecurityException，转到loginException.jsp；

输入用户名admin，再次提交，则抛出Exception，转到Exception.jsp；

输入用户名admin，年龄18，再次提交，则抛出SQLException，转到SQLException.jsp；

最后，输全三个输入（admin/18/13800138000），再次提交，转到成功页面！

posted @ 2013-12-22 19:16 那些年的事儿阅读(514) 评论(0) 编辑收藏举报

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