struts2除了自身提供的类型转换以为,还允许自定义类型转换器,首先表单中的name属性必须和action中的属性同名,然后编写自定义的TypeConverter,可以实现TypeConverter接口,也可以继承DefaultTypeConverter来实现,最简单的是继承StrutsTypeConverter。不过前者比较复杂,后者比较方便。完成类型转换器以后,再将类型转换器注册,这样就能使用了,注册的时候,可以注册为局部类型转换器和全局类型转换器。
<%@ page language="java" contentType="text/html" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s" %>
<!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=UTF-8">
<title>Insert title here</title>
</head>
<body>
<s:form action="loginUser.action" method="post">
<s:textfield name="user" label="username"></s:textfield>
<s:submit value="submit"></s:submit>
</s:form>
</body>
</html>
Action类:
package com.randy.action;
import com.opensymphony.xwork2.ActionSupport;
import com.randy.entity.User;
public class LoginUserAction extends ActionSupport {
private static final long serialVersionUID = -2780543136638232430L;
private User user;
public String execute() {
if("randy".equals(user.getUsername())&&"jin".equals(user.getPassword())) {
return SUCCESS;
}
return LOGIN;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
}
类型转换器:
package com.randy.convertor;
import java.util.Map;
import com.opensymphony.xwork2.conversion.impl.DefaultTypeConverter;
import com.randy.entity.User;
public class UserConvertor extends DefaultTypeConverter {
public Object convertValue(Map context, Object value, Class toType) {
if (toType == User.class) {
String[] params = (String[]) value;
User user = new User();
String[] userValues = params[0].split(",");
user.setUsername(userValues[0]);
user.setPassword(userValues[1]);
return user;
} else if (toType == String.class) {
User user = (User) value;
return user.getUsername() + "," + user.getPassword();
}
return null;
}
}
注册文件,LoginUserAction-conversion。properties(局部的):
user=com.randy.convertor.UserConvertor
此文件放在与action同包中。
转换器一般都提供两者的互相转换。
context是类型转换的上下午环境,value是要转换的值,toType是目标转换类型。
全局类型转换器的话,配置文件中的内容为:
com.randy.entity.User=com.randy.convertor.UserConvertor

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