Struts2 自定义类型转换器的简单示例

来源：互联网发布：凯瑞欧文数据编辑：程序博客网时间：2024/06/06 04:46

1. Coordinate坐标实体：

package com.huey.entity;/** *  * @author Huey2672 * */public class Coordinate {private double x;private double y;public double getX() {return x;}public void setX(double x) {this.x = x;}public double getY() {return y;}public void setY(double y) {this.y = y;}public Coordinate() {}public Coordinate(double x, double y) {this.x = x;this.y = y;}@Overridepublic String toString() {return "(" + x + ", " + y + ")";}}

2. 自定义类型转换器，需要实现TypeConverter接口，TypeConverter的接口定义如下：

public abstract interface TypeConverter {public Object convertValue(Map context, Object target, Member member,String propertyName, Object value, Class toType);}

但是接口中的方法太过复杂，可以通过TypeConverter接口的实现类DefaultTypeConverter来实现自定义类型转换器：

package com.huey.converter;import java.util.Map;import com.huey.entity.Coordinate;import ognl.DefaultTypeConverter;/** * Coordinate的类型转换器 * @author Huey2672 * */public class CoordinateConverter extends DefaultTypeConverter {@Overridepublic Object convertValue(Map context, Object value, Class toType) {if (toType == Coordinate.class) {// 返回的请求参数是一个字符串数组String[] params = ((String[])value)[0].split(",");double x = Double.valueOf(params[0]);double y = Double.valueOf(params[1]);return new Coordinate(x, y);} else if (toType == String.class) {Coordinate coordinate = (Coordinate)value;return coordinate.toString();}return null;}}

Struts2还提供了一个StrutsTypeConverter抽象类，这个抽象类是DefaultTypeConverter的子类，简化了类型转换器的实现：

package com.huey.converter;import java.util.Map;import org.apache.struts2.util.StrutsTypeConverter;import com.huey.entity.Coordinate;/** * Coordinate的类型转换器 * @author Huey2672 * */public class CoordinateConverter extends StrutsTypeConverter {@Overridepublic Object convertFromString(Map context, String[] value, Class toClass) {String[] params = value[0].split(",");double x = Double.valueOf(params[0]);double y = Double.valueOf(params[1]);return new Coordinate(x, y);}@Overridepublic String convertToString(Map context, Object obj) {Coordinate coordinate = (Coordinate)obj;return coordinate.toString();}}

3. 注册类型转换器，方式有三种：

1) 局部注册：在CoordinateAction相同路径下编写配置文件CoordinateAction-conversion.properties：

coordinate=com.huey.converter.CoordinateConverter

2) 全局注册：在src目录下编写配置文件xwork-conversion.properties：

com.huey.entity.Coordinate=com.huey.converter.CoordinateConverter

3) Annotation注册：

4. CoordinateAction：

package com.huey.action;import com.huey.entity.Coordinate;import com.opensymphony.xwork2.ActionSupport;/** *  * @author Huey2672 * */public class CoordinateAction extends ActionSupport {private Coordinate coordinate;public Coordinate getCoordinate() {return coordinate;}public void setCoordinate(Coordinate coordinate) {this.coordinate = coordinate;}public String show() throws Exception {return "success";}}

5. 配置struts.xml文件：

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN" "http://struts.apache.org/dtds/struts-2.1.dtd"><struts><package name="coordinate" extends="struts-default"><action name="show" class="com.huey.action.CoordinateAction" method="show"><result name="success">show.jsp</result><!-- 类型转换失败时，将转入input视图 --><result name="input">index.jsp</result></action></package></struts>

6. index.jsp和show.jsp页面：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme() + "://"+ request.getServerName() + ":" + request.getServerPort()+ path + "/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><title>Index</title></head><body><form action="show" method="post">请输入坐标：<input type="text" name="coordinate"><br/><input type="submit" value="确定"></form></body></html>

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme() + "://"+ request.getServerName() + ":" + request.getServerPort()+ path + "/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><base href="<%=basePath%>"><title>Show</title></head><body>坐标：${coordinate}</body></html>

7. 在index.jsp页面的输入框中输入“22.3,75”，然后提交，跳转到show.jsp页面中显示为：坐标：(22.3, 75.0)