struts2学习笔记之十二:struts2对异常的自动处理

时间：2021-11-05 14:48:47
在UserAction类中引发异常,但是不处理 
package com.djoker.struts2;

import java.util.Date;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.Action;

public class UserAction {

    private String username;

    private String password;

    private Date createDate;

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    public Date getCreateDate() {

        return createDate;

    }

    public void setCreateDate(Date createDate) {

        this.createDate = createDate;

    }

    public String addUser() throws Exception {

        if("admin".equals(username)){

            throw new UserNotFoundException("账号没有找到");

        }

        ServletActionContext.getRequest().setAttribute("username", username);

        ServletActionContext.getRequest().setAttribute("password", password);

        ServletActionContext.getRequest().setAttribute("createDate", createDate);

        return Action.SUCCESS;

    }

}
UserNotFoundException.java类
package com.djoker.struts2;

public class UserNotFoundException extends RuntimeException {

    public UserNotFoundException() {

        super();

        // TODO Auto-generated constructor stub

    }

    public UserNotFoundException(String message, Throwable cause) {

        super(message, cause);

        // TODO Auto-generated constructor stub

    }

    public UserNotFoundException(String message) {

        super(message);

        // TODO Auto-generated constructor stub

    }

    public UserNotFoundException(Throwable cause) {

        super(cause);

        // TODO Auto-generated constructor stub

    }

}
配置文件中可以配置全局异常和局部异常
<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE struts PUBLIC

    "-//Apache Software Foundation//DTD Struts Configuration 2.1.7//EN"

    "http://struts.apache.org/dtds/struts-2.1.7.dtd">

<struts>

    <package name="user" extends="struts-default" namespace="/user">

        <global-exception-mappings>

            <exception-mapping result="error" exception="com.djoker.struts2.UserNotFoundException"></exception-mapping>

        </global-exception-mappings>

        <action name="*User" class="com.djoker.struts2.UserAction" method="{1}User">

            <exception-mapping result="error" exception="com.djoker.struts2.UserNotFoundException"></exception-mapping>

            <result>/success.jsp</result>

            <result name="error">/error.jsp</result>

        </action>

    </package>

</struts>
错误后的跳转页面error.jsp,可以使用el表达式取得异常信息
<%@ page language="java" contentType="text/html; charset=GB18030"

    pageEncoding="GB18030"%>

<!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=GB18030">

<title>Insert title here</title>

</head>

<body>

<h1>登录失败</h1>

<!-- 获取异常信息 -->

${exception.message }<br>

<!-- 获取异常堆栈信息 -->

${exceptionStack }<br>

</body>

</html>

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