当接受表单参数,向页面保持数据时。要用到Struts访问Servlet 的API 。下面只做参考,有错误或不同意见可以发送邮箱2440867831@qq.com 。建议大家看struts文档,源代码
1.struts2通过ActionContext访问
com.opensymphony.xwork2.ActionContext;类有很多方法这里只列举几个常用的方法;
列举个小例子
Struts2的核心配置web.xml 就不做说明了 。前面已经操作过;
Struts.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<!-- 2.变量设置 在Struts.xml文件里面配置 -->
<!--i18n :国际化 解决post提交乱码。输出中文乱码 省去过滤器字节编码-->
<constant name="struts.i18n.encoding" value="UTF-8"></constant>
<constant name="struts.devMode " value="true"></constant>
<constant name="struts.action.extension" value="action,,"></constant> <package name="hello" namespace="/" extends="struts-default">
<!-- 3注意 这里没有method属性 默认对应的是Action类的execute方法 -->
<action name="Demo1" class="com.sturts2.day02.action.RequestDemo1">
<result name="success">/demo2.jsp</result>
</action>
</package>
</struts>
RequestDemo1.java Action类
public class RequestDemo1 extends ActionSupport{
@Override
public String execute() throws Exception {
//ac 相当于Servlet 的request
ActionContext ac=ActionContext.getContext();
Map<String ,Object> paramMap=ac.getParameters();
for(String key: paramMap.keySet()){
String [] value=(String[]) paramMap.get(key);
System.out.println(key+" "+value[0]);
} ac.put("request1", "张三");
ac.getSession().put("session1","李四");
ac.getApplication().put("application1", "王五");
return SUCCESS;
}
}
demo1.jsp
<body>
<h1>访问Servlet API 方式之一</h1>
<form action="${pageContext.request.contextPath}/Demo1.action" method="post">
姓名:<input type="text" name="name"><br/>
年龄:<input type="text" name="age"><br/>
<input type="submit" value="提交">
</form>
</body>
demo2.jsp
<body>
<h1>获取数据</h1>
requet: ${request1 } <br/><br/>
session: ${session1 } <br/><br/>
application: ${application1 } <br/><br/>
</body>
在服务器上运行 ,打开demo1 :
输入数据提交表单: 控制台显示
浏览器跳转页面:
2.通过特定接口访问
Struts2 的ActionContext访问Servlet API 无法直接获得Servlet API 实例。以下接口可以直接访问Servlet API ;
- ServletRequestAware :实现该接口的Action可以直接访问web应用的HttpServletRequest
- ServletResponseAware :实现该接口的Action可以直接访问web应用的HttpServletResponse
- SessionAware :实现该接口的Action可以直接访问web应用的TttpSession
- ServletContextAware :实现该接口的Action可以直接访问web应用的ServletContex实例
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="api" namespace="/" extends="struts-default"> <action name="Demo5Action" class="com.sturts2.day02.b_api.Demo5Action">
<result name="success" >/api.jsp</result>
</action> </package>
</struts>
3.通过ServletActionContext访问
借助ServletActionContext 类,避免action实现ServletRequestAware ,ServletResponseAware、SessionAware 和ServletContextAware 等 XxxAware接口。但Action直接与ServletAPI耦合,不利于程序的解耦。建议使用ActionContext
代码如下:
- static HttpServletResquest getRequest(); 获取Web应用HttpServletResquest对象
- static HttpServletResponse getResponse(); 获取Web应用HttpServletResponse对象
- static ServletContext getServletContext(); 获取Web应用ServletContext对象
- static PageContext getPageContext(); 获取Web应用pageContext对象
struts.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="api" namespace="/" extends="struts-default"> <action name="Demo5Action" class="com.sturts2.day02.b_api.Demo5Action">
<result name="success" >/api.jsp</result>
</action> </package>
</struts>
Action类
package com.sturts2.day02.b_api; import javax.servlet.http.HttpServletRequest; import org.apache.struts2.interceptor.ServletRequestAware; import com.opensymphony.xwork2.ActionSupport; public class Demo5Action extends ActionSupport implements ServletRequestAware {
private HttpServletRequest request;
@Override
public String execute() throws Exception {
System.out.println("原生request:"+request);
return SUCCESS;
} @Override
public void setServletRequest(HttpServletRequest request) {
this.request=request;
} }
api.jsp
<body>
request:${request1 } <br/>
session:${session1 } <br/>
application:${application1 } <br/> </body>
页面显示:
控制台输出