struts form类型转换问题,通过自定义convert类来实现类型转换二
在上一文中我们是通过自己写一个实现了Convert接口的类，并通过一个Serverlet在init的时候注册这个Convert。
但这样实现不够好。
在struts中可以通过插件来实现。
完整代码如下：
convert.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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>
<form action="convertAction.do" method="post">
intvalue:<input type="text" name="intval"/><br>
doublevalue:<input type="text" name="doubleval"/><br>
booleanvalue:<input type="text" name="booleanval"/><br>
utildatevalue:<input type="text" name="dateval"/><br>
<input type="submit" value="submit"/>
</form>
</body>
</html>
form.
package com.lwf.struts.form;
import java.util.Date;
import org.apache.struts.action.ActionForm;
public class ConvertForm extends ActionForm {
private int intval;
private double doubleval;
private boolean booleanval;
private Date dateval;
public int getIntval() {
return intval;
}
public void setIntval(int intval) {
this.intval = intval;
}
public double getDoubleval() {
return doubleval;
}
public void setDoubleval(double doubleval) {
this.doubleval = doubleval;
}
public boolean isBooleanval() {
return booleanval;
}
public void setBooleanval(boolean booleanval) {
this.booleanval = booleanval;
}
public Date getDateval() {
return dateval;
}
public void setDateval(Date dateval) {
this.dateval = dateval;
}
}
action
package com.lwf.struts.action;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
public class ConvertAction extends Action {
public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
return mapping.findForward("success");
}
}
结果：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!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>
intvalue:${convertForm.intval }<br>
doublevalue:${convertForm.doubleval }<br>
booleanvalue:${convertForm.booleanval }<br>
utildatevalue:${convertForm.dateval }<br>
</body>
</html>
配置：
<action path="/convertAction" type="com.lwf.struts.action.ConvertAction" name="convertForm" scope="request"> <forward name="success" path="/convertResult.jsp"></forward> </action>
<form-bean name="convertForm" type="com.lwf.struts.form.ConvertForm"></form-bean>
下面是自定义的convert类，用来将String类转换为java.util.Date类型
package com.lwf.struts.util;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.commons.beanutils.Converter;
public class UtilDateConverter implements Converter {
public UtilDateConverter(Object object) {
}
public Object convert(Class type, Object value) {
if(value == null){
return value;
}
if(value instanceof Date){
return value;
}
if(value instanceof String){
try {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
return sdf.parse((String)value);
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return null;
}
}
以下代码关键：UtilDateConvertPlugIn用来实现PlugIn接口，并实现init方法
package com.lwf.struts.util;
import java.util.Date;
import javax.servlet.ServletException;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.PlugIn;
import org.apache.struts.config.ModuleConfig;
public class UtilDateConvertPlugIn implements PlugIn {
public void destroy() {
}
public void init(ActionServlet arg0, ModuleConfig arg1)
throws ServletException {
ConvertUtils.register(new UtilDateConverter(null), Date.class);
}
}
配置：
<plug-in className="com.lwf.struts.util.UtilDateConvertPlugIn" ></plug-in>
这样Struts启动的时候会加载这个UtilDateConvertPlugIn并执行init方法。。
是不是比新建一个servlet更合理呢。。