java struts2入门学习---自定义类型转换

2023-01-07 21:02:31

自定义类型转换器的作用就是将struts无法识别的类型转换成自己所需要的.

比如输入:广东-东莞-虎门,对应的输出时能输出:广东省东莞市虎门(镇/区)

这里涉及到的知识点即是将String转换为任意的JavaBean类型.

一.实现代码

程序配置入口:struts.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC

    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"

    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

    <!--<include file="config/upload.xml"></include> -->

    <!-- 加载其他配置文件 -->

    <!-- <include file="config/upload-interceptor.xml"></include> -->

    <!-- 加载属性文件－国际化 -->

    <!-- <constant name="struts.custom.i18n.resources" value="message"></constant> -->    <!-- 结果集 -->

    <!-- <include file="config/result_struts.xml"></include> -->

    <!-- 类型转换 -->

    <include file="config/type_struts.xml"></include>

    <!-- 文件下载 -->

    <!-- <include file="config/download_struts.xml"></include> -->

</struts>

注:struts.xml是在项目运行的过程中被加载进入内存的,是项目配置的总入口,这里使用<include>属性加载外部的type_struts.xml

type_struts.xml

<?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE struts PUBLIC

    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"

    "http://struts.apache.org/dtds/struts-2.3.dtd">

<struts>

<!--     <package name="type" extends="struts-default">

        <action name="TypeAction" class="type.TypeAction" method="execute">

            <result name="success" type="dispatcher">

                /WEB-INF/type_success.jsp

            </result>

            <result name="input" type="dispatcher">

                type.jsp

            </result>

        </action>

    </package> -->

    <package name="type" extends="struts-default">

        <action name="TypeSelfAction" class="type.TypeSelfAction" method="execute">

            <result name="success" type="dispatcher">

            /WEB-INF/type_self_success.jsp

            </result>

            <result name="input" type="dispatcher">

            /type_self.jsp

            </result>

        </action>

    </package>

</struts>

注:type_struts.xml是具体负责类型转换时的配置,这里配置了对应的type.TypeSelfAction,以及成功后的跳转页面type_self_success.jsp和程序出错时

的跳转页面type_self.jsp,并将消息回显.

type_self.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"

    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="TypeSelfAction" type="POST">

        <s:textfield label="用户名" name="username" />

        <s:password label="密码" name="password" />

        <s:textfield label="薪水" name="salary" />

        <s:textfield label="生日" name="birthday"/>

        <s:textfield label="地址" name="address"/>

        <s:submit value="提交" name="submit"/>

        <s:reset value="重置"/>

    </s:form>

</body>

</html>

注:type_self.jsp 是用户访问项目的入口,效果图如下所示:

其中使用POST请求方式是为了避免中文乱码等问题,使用struts自带的标签,如s:password,s:textfield等是为了简化开发,并且使错误消息方便回显.

TypeSelfAction.java

package type;

import java.util.Date;

import com.opensymphony.xwork2.ActionSupport;

/**

 * @ClassName: TypeSelfAction

 * @Description: TODO

 * @author: amosli

 * @email:amosli@infomorrow.com

 * @date Feb 13, 2014 11:24:40 PM

 */

public class TypeSelfAction extends ActionSupport {

    private static final long serialVersionUID = -4007160582981636173L;

    private String username;// 用户名

    private String password;// 密码

    private Double salary;// 薪水

    private Date birthday;// 生日

    private Address address;// 地址

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    public Double getSalary() {

        return salary;

    }

    public void setSalary(Double salary) {

        this.salary = salary;

    }

    public Date getBirthday() {

        return birthday;

    }

    public void setBirthday(Date birthday) {

        this.birthday = birthday;

    }

    public Address getAddress() {

        return address;

    }

    public void setAddress(Address address) {

        System.out.println("setaddress:"+address.toString());

        this.address = address;

    }

    public String execute() throws Exception {

        return SUCCESS;

    }

}

注:TypeSelfAction是一个与配置文件type_struts.xml相对应的JavaBean文件.

Address.java

package type;

/**

* @ClassName: Address

* @Description: 定义一个address model

* @author: amosli

* @email:amosli@infomorrow.com

* @date Jan 26, 2014 1:53:33 AM

*/

public class Address {

    private String province;// 省份

    private String city;// 城市

    private String area;// 区域

    public Address(){

    }

    public Address(String province, String city, String area) {

        super();

        this.province = province;

        this.city = city;

        this.area = area;

    }

    public String getProvince() {

        return province;

    }

    public void setProvince(String province) {

        this.province = province;

    }

    public String getCity() {

        return city;

    }

    public void setCity(String city) {

        this.city = city;

    }

    public String getArea() {

        return area;

    }

    public void setArea(String area) {

        this.area = area;

    }

    public String toString() {

        return this.province+"省 "+this.city+"市 "+this.area+"(镇/区)";

    }

}

注:Address是关于地址的JavaBean,其分为省份,市,区域三级.

为了实现自定义类型转换还必须实现StrutsTypeConverter的扩展,这里要手动写两个方法将JavaBean转为String和将String转为JavaBean.

TypeAddressConverter.java

package type;

import java.util.Map;

import org.apache.struts2.util.StrutsTypeConverter;

/**

 * @ClassName: TypeAddressConverter

 * @Description: 自定义类型转换器,继承自StrutsTypeConverter,可以将String转换成任意javaBean对象

 * @author: amosli

 * @email:amosli@infomorrow.com

 * @date Feb 13, 2014 11:42:42 PM

 */

public class TypeAddressConverter extends StrutsTypeConverter {

    public TypeAddressConverter() {

        System.out.println("constructor!");

    }

    //将String转为对象返回

    public Object convertFromString(Map context, String[] values, Class toClass) {

        System.out.println("convertFromString");

        // System.out.println("context:"+context);

        // System.out.println("class:"+toClass);

        // System.out.println("values:"+Arrays.toString(values));

        if (Address.class == toClass) {// 判断类型是否为将要转成的JavaBean

            String[] split = values[0].toString().split("-");//页面中的字符串,下标为0表示第一个字符串,这里如果有多个可以依此类推.

            String province = split[0];// 省份

            String city = split[1];// 市

            String area = split[2];// 区

            Address address = new Address(province, city, area);

            return address;

        }

        return null;

    }

    //将对象转为String返回

    public String convertToString(Map context, Object o) {

        System.out.println("convertToString");

        if (o instanceof Address) {// 判断对象类型是否为Adress

            Address adr = (Address) o;

            return adr.toString();

        }

        return null;

    }

}

注:这里是自定义类型转换的核心代码,即如何将一个JavaBean转为String和将String转为JavaBean.

为了调用上面的方法还必须加一个配置.

xwork-conversion.properties

#JavaBean=self defined typeconverter

type.Address=type.TypeAddressConverter

注:一般情况下应将xwork-conversion.properties存放在src目录下,我这里用的是Maven管理的,xwork-conversion.properties是放在resources目录下的,如下图所示:

自此所有配置结束.

二.效果图

1.点击提交按钮:

2.点击重置按钮:

本文源码: struts2 自定义类型转换器 https://github.com/amosli/strut2_learn

码农公寓

一.实现代码

二.效果图

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