问题:如何验证数组的元素?
我想编写一个简单的应用程序,要求用户使用struts2输入10个数字。
enter.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Enter 10 numbers!</title>
</head>
<body>
<h3>Please enter 10 numbers</h3>
<s:form action="next.action" method="post" validate="true">
<s:iterator var="i" begin="0" end="9">
<s:label value="Number %{#i+1}"/>
<s:textfield name="number" key="label.number" size="20"/>
</s:iterator>
<s:submit method="execute" key="label.next" align="center" />
</s:form>
</body>
</html>
我使用迭代器生成10个textarea供用户输入数字。我希望所有领域都是必需的。
NextAction.java
import com.opensymphony.xwork2.ActionSupport;
import java.util.ArrayList;
public class NextAction extends ActionSupport{
private Integer[] number;
public Integer[] getNumber() {
return number;
}
public void setNumber(Integer[] number) {
this.number = number;
}
public String execute(){
return "success";
}
}
这个班级唯一的属性是数字。请注意,因为我生成了10个同名“number”的textarea,我在这个类中得到的“数字”将是一个长度为10的Integer数组。当我没有使用下面的验证时,我可以很容易地得到用户输入的数字(即数字[i]),并在另一个jsp中显示它们。
的web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>Number</display-name>
<welcome-file-list>
<welcome-file>enter.jsp</welcome-file>
</welcome-file-list>
<filter>
<filter-name>struts2</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>struts2</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>
struts.xml中
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
<constant name="struts.custom.i18n.resources" value="ApplicationResources" />
<package name="default" extends="struts-default" namespace="/">
<action name="forward" class="NextAction">
<result name="success">success.jsp</result>
result name="input">enter.jsp</result>
</action>
</package>
</struts>
个动作-validation.xml中
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE validators PUBLIC
"-//OpenSymphony Group//XWork Validator 1.0.2//EN"
"http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd">
<validators>
<field name="number"> <!-- The field 'number' here is actually holding an array -->
<field-validator type="required">
<message key="errors.required"/>
</field-validator>
<field-validator type="int">
<param name="min">1</param>
<param name="max">100</param>
<message key="errors.number"/>
</field-validator>
</field>
</validators>
但是当我添加这个验证时,因为字段“number”是数组,那么这个验证将不起作用。(如果只有一个textarea命名为'number',这个验证就没问题了。但我们有10个)
我的问题是如何验证数组的每个元素,我们从提交的表单中获取?希望我的问题很明确。
谢谢
答案 0 :(得分:3)
您不太可能重复使用此验证器,因此只需在操作中使用validate:
import com.opensymphony.xwork2.ActionSupport;
import java.util.ArrayList;
public class NextAction extends ActionSupport{
private Integer[] number;
public Integer[] getNumber() {
return number;
}
public void setNumber(Integer[] number) {
this.number = number;
}
//Following is default behaviour so it is not worth writing
//public String execute(){
// return "success";
//}
//add validation in action (_not tested_)
public void validate(){
if (number.length > 10){
this.addActionError("Error: More than ten numbers supplied.");
}else if (number.length < 10){
this.addActionError("Error: Less than ten numbers supplied.");
}
for (int i = 0; i < number.length; i++){
if(number[i] < 0){
this.addActionError("Error: Number " + (i + 1) + " is less than zero.");
}else if(number[i] > 100){
this.addActionError("Error: Number " + (i + 1) + " is greater than 100.");
}
}
}
}
然后用<s:actionerror />
显示jsp中的字段错误,或者重写上面的内容以专门命名字段(带索引),在这种情况下你可以使用,你将使用addFieldError方法。有关这些标记的详细信息,请参阅http://struts.apache.org/2.3.1.2/docs/tag-reference.html