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struts的一个容易的包含select下拉框的例子

技术开发2022-07-19 阅读()
appName.length() < 1) {
errors.add("application name", new ActionError("error.appname.required"));
}
return errors;
}
}
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这里是ActionServlet代码,继承Action:
-----------------------------------------------
package com.egi.core.ioblock.action;

import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.struts.action.Action;
import org.apache.struts.action.ActionError;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForward;
import com.egi.core.ioblock.form.LoginForm;
import com.mainet.core.spreadsheet.db.MenusTreeTable;
import com.mainet.core.spreadsheet.ProjectFactory;

/**
*Copyright: Copyright (c) 2002</p> <p>
*@author sjoy
*@created2003年6月4日
*@version1.0
*/

public class LoginAction extends Action {

public ActionForward perform(ActionMapping mapping,
ActionForm form,
HttpServletRequest request,
HttpServletResponse response)
 throws IOException, ServletException {

ActionErrors errors = new ActionErrors();
String appName = ((LoginForm) form).getAppName();

//下面是你所需要的一些逻辑
...
HttpSession session = request.getSession();
...

return mapping.findForward("success");
}
}

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2. 写一个bean,专门用来保存select的option集合。代码如下:
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package com.egi.core.ioblock.util;

import java.io.Serializable;

/**
*Description: This class is a bean, used to represent one option in an HTML
*drop-down 'select' list. It contains two properties - see {@link
*getDisplayName()} and {@link getInternalId()} for a description. Useful in a
*struts Form class for constructing a select list to pass to the jsp with the
*<tt><html:select></tt> and <tt><html:option></tt> tags.</p> <p>
*@author sjoy
*@created2003年6月4日
*@version1.0
*/

public class HtmlSelectOption implements Serializable {
private String id;
private String displayName;

/**
 *Constructor for the HtmlSelectOption object
 */
public HtmlSelectOption() { }

/**
 *Constructor for the HtmlSelectOption object
 *
 *@paramid Description of the Parameter
 *@paramdisplayNameDescription of the Parameter
 */
public HtmlSelectOption(String id, String displayName) {
this.id = id;
this.displayName = displayName;
}

public String getDisplayName() {
return displayName;
}

public void setDisplayName(String displayName) {
this.displayName = displayName;
}

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}
}
-----------------------------------------------

3. ok,接下来从db或者其它地方去取下拉列表中的具体内容;
java.util.Iterator iter = ....;//这里假设从数据库中取得数据
java.util.ArrayList list = new java.util.ArrayList();
String obj;
while(iter.hasNext()){
obj = (String)iter.next();
list.add(new com.egi.core.ioblock.util.HtmlSelectOption(obj,obj));
}
pageContext.setAttribute("appNames", list);

注意:这段逻辑也可以写在ClienetForm中通过javabean的方式在页面上获得这个集合。

4. 然后就是页面上使用啦:)
<html:select property="type">
<html:options collection="appNames" property="id"
 labelProperty="displayName"/>
</html:select>

搞定!

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