Struts学习之路-第二天（Action与Servlet API）
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Struts作为一款Web框架自然少不了与页面的交互，开发过程中我们最常用的request、application、session等struts都为我们进行了一定的封装与处理
一、通过ActionContext获取
| 方法 | 说明 |
| void put(String key,Object value) | 模拟HttpServletRequest中的setAttribute（） |
| Object get(Object key) | 通过参数key查找当前ActionContext中的值 |
| Map getApplication（） | 返回一个Application级的Map对象 |
| static ActionContext getContext（） | 获得当前线程的ActionContext对象 |
| Map getParameters() | 返回一个Map类型HttpSession对象 |
| void put（Object key，Object vlue） | 向前ActionContext对象中存入名值对信息 |
| void setApplication（Map application） | 设置Application上下文 |
| void setSession（Map session） | 设置一个Map类型的Session对象 |
| Map setSession() |
返回一个Map类型的HttpSession对象 |
1.配置web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
2.配置struts.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" "http://struts.apache.org/dtds/struts-2.5.dtd"> <struts> <!--struts中对应mvc的三层是，filterdispatcher->控制层、Action->模型层、Result->视图层--> <package name="test" extends="struts-default"> <!--设置允许动态调用的方法--> <global-allowed-methods>user</global-allowed-methods> <action name="user" class="test.TestAction"> <!--result顾名思义返回结果，name属性与Action中返回的字符串一样,作用就是返回视图--> <result name="success">/success.jsp</result> <result name="user">/user.jsp</result> </action> </package> <!--设置允许动态调用，除了execute()方法之外的其他自定义方法--> <constant name="struts.enable.DynamicMethodInvocation" value="true"></constant> <constant name="struts.i18n.encoding" value="UTF-8"></constant> </struts>
3.在test包下写TestAction类
package test; import com.opensymphony.xwork2.ActionContext; import com.opensymphony.xwork2.ActionSupport; public class TestAction extends ActionSupport{ private static final long serialVersionUID = 1L; //我们也可以通过实现特定接口来获取对应的对象比如ServletRequestAware可以获取到HttpServletRequest //的实例，但是我们需要手动定义该对象，通过接口中的重写的方法来初始化 public String execute(){ return "success"; } public String user(){ // struts通过Action访问servlet中的request、session、application等 ActionContext context = ActionContext.getContext(); context.put("name","request");//默认是request context.getSession().put("name","session");//session context.getApplication().put("name","application");//application return "user"; } }
4.准备页面index.jsp、user.jsp
1)index.jsp
<%-- Created by IntelliJ IDEA. po: zgye Date: 2019/5/11 Time: 12:27 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>$Title$</title> </head> <body> <a href="user">user</a> <a href="user!user.action">select</a> </body> </html>
2)user.jsp
<%-- Created by IntelliJ IDEA. po: zgye Date: 2019/5/11 Time: 13:18 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>用户页面</title> </head> <body> 测试内置对象： ${requestScope.name} ${sessionScope.name} ${applicationScope.name} </body> </html>
5.启动服务点击select超链接测试
二、通过特定接口访问
ActionContext虽然可以间接的访问Servlet API，同时我们有时候也需要直接去访问Servlet API，Struts2为我们提供了对应的接口
1）ServletRequestAware
2）ServletResponseAware
3）ServletContextAware
·······
1.准备web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <filter> <filter-name>struts2</filter-name> <filter-class>org.apache.struts2.dispatcher.filter.StrutsPrepareAndExecuteFilter</filter-class> </filter> <filter-mapping> <filter-name>struts2</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
2.配置struts,xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE struts PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 2.5//EN" "http://struts.apache.org/dtds/struts-2.5.dtd"> <struts> <!--struts中对应mvc的三层是，filterdispatcher->控制层、Action->模型层、Result->视图层--> <package name="test" extends="struts-default"> <!--接口方式测试Servlet API--> <action name="servlet" class="test.TestServletAction"> <result name="servlet">/servlet.jsp</result> </action> </package> </struts>
3.准备TestServletAction.ava
package test; import com.opensymphony.xwork2.ActionSupport; import org.apache.struts2.interceptor.ServletRequestAware; import org.apache.struts2.interceptor.ServletResponseAware; import org.apache.struts2.util.ServletContextAware; import javax.servlet.ServletContext; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class TestServletAction extends ActionSupport implements ServletRequestAware, ServletResponseAware, ServletContextAware { private HttpServletRequest request; private HttpServletResponse response; private ServletContext context; @Override public void setServletRequest(javax.servlet.http.HttpServletRequest httpServletRequest) { request=httpServletRequest; } @Override public void setServletResponse(HttpServletResponse httpServletResponse) { response=httpServletResponse; } @Override public void setServletContext(ServletContext servletContext) { context=servletContext; } @Override public String execute() throws Exception { request.setAttribute("name","request"); request.setAttribute("response",response); context.setAttribute("name","context"); return "servlet"; } }
4.准备servlet.jsp页面
<%-- Created by IntelliJ IDEA. User: zgye Date: 2019/5/12 Time: 12:27 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>servlet测试页面</title> </head> <body> request:${requestScope.name}<br> response:${requestScope.response}<br> context:${applicationScope.name} </body> </html>
5.启动服务请求http://localhost:8080/servlet查看测试结果
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