struts2_struts類型轉換

一.在Servlet中,表單提交的非字元串類型需要手動轉換

　　1.在struts中,表單提供的常見數據類型struts框架自動轉換,無需手動轉換

　　2.在某些情況下,某些自定義類型struts不能完成自動轉換,需要進行手動轉換,如果需要轉換的類型轉換頻率較高時,手動轉換的代碼增多,這時可以使用struts的類型轉換器來進行轉換

二.類型轉換

使用類型轉換的步驟

1. 編寫類型轉換器,繼承StrutsTypeConverter
2. 編寫xwork-conversion.properties配置文件,內容為:要轉換的類型=類型轉換器

 案例:

　　編寫實體類:Point

package com.ahd.entity;

public class Point {
    private int x;
    private int y;
    
    public int getX() {
        return x;
    }
    public void setX(int x) {
        this.x = x;
    }
    public int getY() {
        return y;
    }
    public void setY(int y) {
        this.y = y;
    }
    @Override
    public String toString() {
        return "(" + x + "," + y + ")";
    }
    
}

　　編寫PointAction

package com.ahd.action;

import com.ahd.entity.Point;
import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport;

public class PointAction extends ActionSupport{
    private Point point;
    
    public Point getPoint() {
        return point;
    }
    public void setPoint(Point point) {
        this.point = point;
    }


    @Override
    public String execute() throws Exception {
        // TODO Auto-generated method stub
        System.out.println(point.getX()+point.getY());
        System.out.println(point);
        return Action.SUCCESS;
    }
}

　　xwork-conversion.properties

com.ahd.entity.Point=com.ahd.converter.PointConverter

　　編寫類型轉換器:PointTypeConverter,繼承StrutsTypeConverter類,並重寫convertFromString方法和convertToString方法,

package com.ahd.converter;

import java.util.Map;

import org.apache.struts2.util.StrutsTypeConverter;

import com.ahd.entity.Point;

public class PointConverter extends StrutsTypeConverter{

    @Override
    public Object convertFromString(Map context, String[] values, Class toClass) {
        // TODO Auto-generated method stub
        String value=values[0];
        Point point=new Point();
        
        int x=Integer.parseInt(value.substring(0, value.indexOf(",")));
        int y=Integer.parseInt(value.substring( value.indexOf(",")+1,value.length()));
        
        point.setX(x);
        point.setY(y);
        
        return point;
    }

    @Override
    public String convertToString(Map context, Object o) {
        // TODO Auto-generated method stub
        Point point=(Point)o;
        return "("+point.getX()+","+point.getY()+")";
    }
    
}

　　struts.xml

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

<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
    "struts-2.0.dtd">

<struts>
    <package name="struts2" extends="struts-default" namespace="">
        <action name="point" class="com.ahd.action.PointAction">
            <result>/success.jsp</result>
            <result name="input">/input.jsp</result>
        </action>
    </package>
</struts>

　　web.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app id="WebApp_ID">
    <display-name>struts2_02_modelDrive</display-name>
    
    <filter>
        <filter-name>struts2</filter-name>
        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>struts2</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
</web-app>