Struts 2 学习笔记02

最新推荐文章于 2024-04-06 15:33:48 发布

原创最新推荐文章于 2024-04-06 15:33:48 发布 · 507 阅读

CC 4.0 BY-SA版权

本文深入探讨了Struts2框架中Action类的实现与配置文件的运用，包括页面内的多submit按钮写法、使用include标签重用配置文件、Action别名的设定、为Action指定参数等关键概念。文章详细解析了如何正确设置Action的方法返回值、避免配置冲突，以及如何通过配置文件实现功能模块的复用，旨在帮助开发者掌握Struts2框架的核心用法。

1.一个页面中有多个submit 写法
页面
<s:form action="submit" namespace="">
<s:textfield name="msg" label="Please input content:"/>
<s:submit name="save" value="Save" method="save"/>
<s:submit name="print" value="Print" method="print"/>
</s:form>

struts.xml

 <package name="struts2"  extends="struts-default">
    <action name="submit" class="action.SubmitAction">
         <result name="print">/result.jsp</result>
         <result name="save">/result.jsp</result>
    </action>
 </package>

Action

package action;

import javax.servlet.http.HttpServletRequest;

import org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.ActionSupport;

public class SubmitAction extends ActionSupport implements ServletRequestAware {
	private String msg;
	private javax.servlet.http.HttpServletRequest request;

	@Override
	public void setServletRequest(HttpServletRequest request) {
		// TODO Auto-generated method stub
		this.request = request;
	}

	public String getMsg() {
		return msg;
	}

	public void setMsg(String msg) {
		this.msg = msg;
	}

	public String save() {
		request.setAttribute("result", "Save sucessfully [" + msg + "]");
		return "save";
	}

	public String print() {
		request.setAttribute("result", "Print sucessfully [" + msg + "]");
		return "print";
	}

}

犯的错误：save() 和 print() 方法的返回值写错了，报 No result defined for action action.SubmitAction and result result 错误

2.使用<include>标签重用配置文件

新建一个struts2.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
 <package name="struts2"  extends="struts-default">
    <action name="submit" class="action.SubmitAction">
         <result name="print">/result.jsp</result>
         <result name="save">/result.jsp</result>
    </action>
 </package>

</struts>

在Struts.xml 中include引入

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
"http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
	<include file="struts2.xml"/>
	
 <package name="struts1"  extends="struts-default">
    <action name="sum" class="action.FirstAction">
         <result name="positive">/positive.jsp</result>
         <result name="negative">/negative.jsp</result>
    </action> 
    
    <action name="submit" class="action.SubmitAction">
         <result name="print">/result.jsp</result>
         <result name="save">/result.jsp</result>
    </action>
 </package>

</struts>

犯的错误：多个配置文件中的package 命名也不能重复，比如struts.xml中有 struts1 的package,在Struts2.xml中就不可以再给package命名为struts1

3.Action 别名(感觉和一个页面包含多个Submit写法作用一样)

<package name="demo" extends="struts-default" >
<action name="test" class="action.MyAction">
          ……
</action>
<action name="my" class="action. MyAction" method="my">
          ……
</action>
</package>

①必须保证MyAction类中包含my() 方法

②和在页面传递method参数比较，此方法需要在Struts.xml中配置别名

4、为Action指定参数

<action name="submit" class="action.MyAction">
<param name="param1">value1</param>
<param name="param2">value2</param>
<result name="save" >
/result.jsp
</result>
      ……
</action>

之后在Action类中定义setter方法即可，当struts2在调用execute之前，param1和param2的值就已经是相应参数的值了，因此，在
execute方法中可以直接使用param1和param2。