基于Struts2的自定义类型转换器处理Set集合

本是古典何须时尚 2021-07-24 18:21 400阅读 0赞

**一 视图**

1 input.jsp

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <%@taglib prefix="s" uri="/struts-tags"%>
    <!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>
        <title>Set属性的类型转换</title>
    </head>
    <body>
    <h3>Set属性的类型转换</h3>
    <s:form action="login">
        <s:textfield name="users" label="第一个用户信息"/>
        <s:textfield name="users" label="第二个用户信息"/>
        <s:textfield name="birth" label="用户生日"/>
        <tr>
            <td colspan="2"><s:submit value="转换" theme="simple"/>
            <s:reset value="重填" theme="simple"/></td>
        </tr>
    </s:form>
    </body>
    </html>

2 welcome.jsp

<%@ page language="java" contentType="text/html; charset=GBK"%>
    <%@taglib prefix="s" uri="/struts-tags"%>
    <html>
    <head>
        <title>转换结果</title>
    </head>
    <body>
        <s:actionmessage/>
        <s:property value="users"/>
    
    用户crazyit.org的用户名为：<s:property value="users('crazyit.org').name"/><br/>
    
    用户crazyit.org的密码为：<s:property value="users('crazyit.org').pass"/><br/>
    
    用户fkit的用户名为：<s:property value="users('fkit').name"/><br/>
    
    用户fkit的密码为：<s:property value="users('fkit').pass"/><br/>
    生日为：<s:property value="birth"/><br/>
    </body>
    </html>

**二 配置文件**

<?xml version="1.0" encoding="GBK"?>
    <!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">
    <struts>
        <package name="lee" extends="struts-default">
    
            <action name="login" class="org.crazyit.app.action.LoginAction">
                <result>/WEB-INF/content/welcome.jsp</result>
                <result name="error">/WEB-INF/content/welcome.jsp</result>
            </action>
            <action name="*">
                <result>/WEB-INF/content/{1}.jsp</result>        
            </action>
        </package>
    </struts>

**三 action**

package org.crazyit.app.action;
    
    import com.opensymphony.xwork2.*;
    import java.util.Date;
    import java.util.Set;
    
    public class LoginAction extends ActionSupport
    {
        private Set users;
        private Date birth;
        // users的setter和getter方法
        public void setUsers(Set users)
        {
            this.users = users;
        }
        public Set getUsers()
        {
            return this.users;
        }
        // birth的setter和getter方法
        public void setBirth(Date birth)
        {
            this.birth = birth;
        }
        public Date getBirth()
        {
            return this.birth;
        }
        // 没有提供execute()方法,
        // 将直接使用ActionSupport的execute()方法
    }

**四 转换器**

package org.crazyit.app.converter;
    
    import java.util.*;
    import org.apache.struts2.util.StrutsTypeConverter;
    
    import org.crazyit.app.domain.*;
    
    public class UserConverter extends StrutsTypeConverter
    {
        public Object convertFromString(Map context
            , String[] values, Class toClass)
        {
            Set result = new HashSet();
            for (int i = 0; i < values.length ; i++ )
            {
                // 创建一个User实例
                User user = new User();
                // 只处理请求参数数组第一个数组元素，
                // 并将该字符串以英文逗号分割成两个字符串
                String[] userValues = values[i].split(",");
                // 为User实例的属性赋值
                user.setName(userValues[0]);
                user.setPass(userValues[1]);
                // 将User实例添加到Set集合中
                result.add(user);
            }
            return result;
        }
        public String convertToString(Map context, Object o)
        {
            // 如果待转换对象的类型是Set
            if (o.getClass() == Set.class)
            {
                Set users = (Set)o;
                String result = "[";
                for (Object obj : users )
                {
                    User user = (User)obj;
                    result += "<" + user.getName()
                        + "," + user.getPass() + ">";
                }
                return result + "]";
            }
            else
            {
                return "";
            }
        }
    }

对应的属性文件

#指定users属性的类型转换器是UserConverter
    users= org.crazyit.app.converter.UserConverter
    # 指定users集合属性里集合元素的索引属性是name
    KeyProperty_users=name

**五 领域模型**

package org.crazyit.app.domain;
    
    
    public class User
    {
        private String name;
        private String pass;
    
        // name的setter和getter方法
        public void setName(String name)
        {
            this.name = name;
        }
        public String getName()
        {
            return this.name;
        }
    
        // pass的setter和getter方法
        public void setPass(String pass)
        {
            this.pass = pass;
        }
        public String getPass()
        {
            return this.pass;
        }
    
        public boolean equals(Object obj)
        {
            // 如果待比较的两个对象是同一个对象，直接返回true
            if(this == obj)
            {
                return true;
            }
            // 只有当obj是User对象
            if (obj != null && obj.getClass() == User.class)
            {
                User user = (User)obj;
                // 两个对象的name属性相等即认为二者相等
                return this.getName().equals(user.getName());
            }
            return false;
        }
        // 根据name计算hashCode
        public int hashCode()
        {
            return name.hashCode();
        }
    }

**六 测试**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1][]

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1]: /images/20210724/ff3ac07480b54e5797b7aaff2b7e4c64.png