使用addFieldError方法和s:fieldError标签简单处理数据校验
struts.xml配置文件如下:
<action name="user" class="xidianlili.struts2.user.action.UserAction">
<result>/Useradd_success.jsp</result>
<result name="error">/Useradd_error.jsp</result>
</action>
action类的java文件如下:
package xidianlili.struts2.user.action;
import com.opensymphony.xwork2.ActionSupport;
import xidianlili.struts2.user.model.User;
public class UserAction extends ActionSupport {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String add() {
if(name==null||!name.equals("admin"))
{
return "error";
}else{
System.out.println("name:"+name);
return SUCCESS;
}
}
}
在action类中定义属性,用属性接受参数,进行参数判断不是null和admin都是error,返回error对应的jsp文件,那么怎么把error信息返回到jsp文件中?首先修改add方法:this.addFieldError(fieldName, errorMessage);添加错误信息,而且一个属性可以添加多个错误信息
public String add() {
if(name==null||!name.equals("admin"))
{
//this.addFieldError(fieldName, errorMessage);
this.addFieldError("name","name is error");
this.addFieldError("name", "name is to long");
return "error";
}else{
System.out.println("name:"+name);
return SUCCESS;
}
那么对应的jsp文件如何接受这些错误信息呢?利用<%@taglib uri="/struts-tags" prefix="s" %>并且body里最后加入<s:debug></s:debug>会出现调试框
<?xml version="1.0" encoding="GB18030" ?>
<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>
<%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030" />
<title>Insert title here</title>
</head>
<body>
User Add Error!
<s:fielderror fieldName="name" theme="simple"/>
<br />
<s:property value="errors.name[0]"/>
<s:debug></s:debug>
</body>
</html>
运行结果如下:点击debug,出现下面视图,我们的s执行ValueStack和下面的StackContext,用<s:property value="errors.name[0]"/> property 可以按照名字取valuestack通过fieldname取到error名称,相当于map,里面有property name是key,property vale是值,errors.name的值就是{[name is error,name is too long]},相当于数组,那么errors.name[0]就是取到[内容]