Struts自定义类型转换器实战

阳光穿透心脏的1/2处 2021-07-24 11:06 463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>局部类型转换器</title>
    </head>
    <body>
    <h3>局部类型转换器</h3>
    <s:form action="login">
        <s:textfield name="user" label="用户"/>
        <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 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>转换结果</title>
    </head>
    <body>
        <s:actionmessage/>
        用户名为:<s:property value="user.name"/><br/>
        密码为：<s:property value="user.pass"/><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 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;
        }
    
    }

**四 自定义类型转换器**

package org.crazyit.app.converter;
    
    import java.util.Map;
    import ognl.DefaultTypeConverter;
    
    import org.crazyit.app.domain.*;
    
    public class UserConverter extends DefaultTypeConverter
    {
        // 类型转换器必须重写convertValue方法，该方法需要完成双向转换
        public Object convertValue(Map context
            , Object value, Class toType)
        {
            // 当需要将字符串向User类型转换时
            if (toType == User.class )
            {
                // 系统的请求参数是一个字符串数组
                String[] params = (String[])value;
                // 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 = params[0].split(",");
                // 为User实例赋值
                user.setName(userValues[0]);
                user.setPass(userValues[1]);
                // 返回转换来的User实例
                return user;
            }
            else if (toType == String.class )
            {
                // 将需要转换的值强制类型转换为User实例
                User user = (User) value;
                return "<" + user.getName() + ","
                    + user.getPass() + ">";
            }
            return null ;
        }
    }

**五 action**

package org.crazyit.app.action;
    
    import com.opensymphony.xwork2.ActionSupport;
    
    import org.crazyit.app.domain.*;
    
    public class LoginAction extends ActionSupport
    {
        private User user;
    
        // user的setter和getter方法
        public void setUser(User user)
        {
            this.user = user;
        }
        public User getUser()
        {
            return this.user;
        }
        public String execute() throws Exception
        {
            if (getUser().getName().equals("crazyit.org")
                && getUser().getPass().equals("leegang") )
            {
                addActionMessage("登录成功！");
                return SUCCESS;
            }
            addActionMessage("登录失败！！");
            return ERROR;
        }
    }

对应的转换属性文件

#指定Action的user属性需要使用UserConverter类来完成类型转换
    user=org.crazyit.app.converter.UserConverter

**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][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70]: /images/20210724/30e5e85a6e534580984a3266993b703f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1]: /images/20210724/3064c42655984a42960e05d4a9f6fe3a.png