Struts2内建类型转换器数据器使用简介
struts2 内建了类型转换器，可以方便的将我们在页面上输入的字符串数据转换成JavaBean中的Boolean,Float,Integer,Double,Long等数据类型，在无法转换成功时，还可以给出错误提示，非常方便
首先简历JavaBean:
package
HelloWorld;
public
class
User
{
private String username; private Integer password; private String[] books;
public String[] getBooks() {
return books;
} public void setBooks(String[] books) { this.books = books; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public Integer getPassword() { return password; } public void setPassword(Integer password) { this.password = password; } 
}
编写Action,需要继承ActionSupport,在action中有两个变量，一个是User类，一个是birth属性
我们定义birth属性和user类中的password属性都必须是Integer类型
package
HelloWorld;
import
com.opensymphony.xwork2.ActionSupport;
public
class
LoginAction
extends
ActionSupport
{ private String tip;private User user;private Integer birth;public Integer getBirth() { return birth;}public void setBirth(Integer birth) { this.birth = birth;}public String execute() throws Exception{ System.out.println(this.getUser().getUsername()); System.out.println(this.getUser().getPassword()); return SUCCESS; }public User getUser() { return user;}public void setUser(User user) { this.user = user;}public String getTip() { return tip;}public void setTip(String tip) { this.tip = tip;} }
web.xml
<?
xml version="1.0" encoding="UTF-8"
?>
<
web-app
version
="2.5"
xmlns
="http://java.sun.com/xml/ns/javaee"
xmlns:xsi
="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation
="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
>
<
filter
>
<
filter-name
>
struts2
</
filter-name
>
<
filter-class
>
org.apache.struts2.dispatcher.FilterDispatcher
</
filter-class
>
</
filter
>
<
filter-mapping
>
<
filter-name
>
struts2
</
filter-name
>
<
url-pattern
>
/*
</
url-pattern
>
</
filter-mapping
>
</
web-app
>
struts.xml (WEB-INF/classes下)
<?
xml version="1.0" encoding="GBK"
?>
<!
DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN" "http://struts.apache.org/dtds/struts-2.0.dtd"
>
<
struts
>
<
package
name
="struts"
extends
="struts-default"
>
<
action
name
="Login"
class
="HelloWorld.LoginAction"
>
<
result
name
="input"
>
/helloworld/index.jsp
</
result
>
<
result
name
="success"
>
/helloworld/welcome.jsp
</
result
>
<
result
name
="error"
>
/helloworld/error.jsp
</
result
>
</
action
>
</
package
>
</
struts
>
struts.properties(WEB-INF/classes下)
struts.custom.i18n.resources=messageResource
信息录入页面：
<%@ page language="java" contentType="text/html; charset=gb2312"
pageEncoding="gb2312"%>
<%@ taglib prefix="s" uri="/struts-tags" %>
<html>
<head>
<title></title>
</head>
<body>
<div style="color:red">
<s:fielderror />
</div>
<s:form action="Login">
<s:textfield name="user.username" key="username"></s:textfield>
<s:textfield name="user.password" key="password"></s:textfield>
<s:textfield name="birth" key="password"></s:textfield>
<s:submit value="login"></s:submit>
</s:form>
</body>
</html>
信息展示页面：
<%@ page language="java" contentType="text/html; charset=gb2312"
pageEncoding="gb2312"%>
<%@ page isELIgnored="false" %>
<%@ taglib prefix="s" uri="/struts-tags" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title></title>
</head>
<body>
<body>
转换成功!<br>
用户1的用户名为：<s:property value="user.username"/><br>
用户1的密码为：<s:property value="user.password"/><br>
</body>
</html>
我们在资源文件中加入：
xwork.default.invalid.fieldvalue={0}类型转换错误，运行index.jsp.,在三个输入框中都输入admin,则会出现以下提示：
user.password字段类型转换失败
birth字段类型转换失败
在资源文件中定义的是全局转换错误提示的内容，如果想对具体Action中的字段进行提示，则编写ActionName.properties,本文中对应的就是LoginAction.properties,放在和Action同一个目录下，内容格式如下：invalid.fieldvalue.birth （其中birth为action中属性名）
本文LoginAction.properties内容为：invalid.fieldvalue.birth=生日必须为数字
再次运行index.jsp.结果如下：
user.password字段类型转换失败
生日必须位数字