struts2中的异常处理

异常处理后,能够提供友好的用户界面,而不是一些错误的代码信息.

利用struts2的异常处理机制可以很方便的实现异常处理,你不再 需要在Action中捕获异常，并抛出相关的异常了,这些都交给拦截器来帮你做了。在struts-default.xml中己经设置了拦截器,因此我们 可以直接使用声明式异常.struts2-default-xml声明的拦截器如下:

 

<interceptors>
<interceptor name="exception"
class="com.opensymphony.xwork.interceptor.ExceptionMappingInterceptor"/>
interceptors>

 

 

异常的类型可以分为两种:局部异常映射和全局异常映射

 

当Action抛出异常时,会在局部中和全局中查找与之相匹配的异常,如果局部和全局中都有满足的异常映射,以局部的为准. 例子说明:

 

action:

 

public class LogonAction {
    private String userName;
    private String userPwd;
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getUserPwd() {
        return userPwd;
    }
    public void setUserPwd(String userPwd) {
        this.userPwd = userPwd;
    }
    public String execute() throws Exception{
        if(userName.equals("callan") && userPwd.equals("fjf")){
            ActionContext.getContext().getSession().put("userName", "callan");
            return "succee";
        } else {
            throw new SQLException(“用户名密码不正确”);
        }
    }
}

public class LogonAction {
	private String userName;
	private String userPwd;
	public String getUserName() {
		return userName;
	}
	public void setUserName(String userName) {
		this.userName = userName;
	}
	public String getUserPwd() {
		return userPwd;
	}
	public void setUserPwd(String userPwd) {
		this.userPwd = userPwd;
	}
	public String execute() throws Exception{
		if(userName.equals("callan") && userPwd.equals("fjf")){
			ActionContext.getContext().getSession().put("userName", "callan");
			return "succee";
		} else {
			throw new SQLException(“用户名密码不正确”);
		}
	}
}

 

配置文件:

<package name="logon" extends="struts-default">

       <global-exception-mappings>
            <exception-mapping result="all" exception="java.lang.Exception">
                exception-mapping>
        global-exception-mappings>
        <action name="logon" class="com.LogonAction">
            <result name="succee">/logon/welcome.jspresult>
            <result name="error">/logon/error.jspresult>
            <exception-mapping result="sql" exception="java.sql.SQLException"/>exception-mapping>
            <exception-mapping result="nullPoint" exception="java.lang.NullPointerException">exception-mapping>
            <result name="nullPoint">/logon/nullpoint.jspresult>
            <result name="sql">/logon/sql.jspresult>
             <result name="all">/logon/all.jspresult>
        action>
    package>

      
       
        	
                
        
        
            /logon/welcome.jsp
            /logon/error.jsp
            
            
            /logon/nullpoint.jsp
            /logon/sql.jsp
             /logon/all.jsp
        
    

 

上面是个用户登陆的action及配置,定义了两个局部异常和一个全局异常
当输入的用户名和密码不为callan和fjf时,会抛出SQLException异常,局部异常配置起作用,会定向到sql.jsp,如果注释局部sql异常,全局异常起作用,定向到all.jsp

 

 

可以使用Struts2的标签来输出异常信息

例如sql.jsp页面

   
 
可以输出 用户名密码不正确