Struts2(八)访问Servlet API

2019-11-14 23:32:14

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Struts2(八)访问Servlet API一、Struts2中的Servlet API1.1、struts2的Action实现了MVC中C层的作用

针对请求用户显示不同的信息

登录后段保存用户信息 ----session

保存当前在线人数等功能---application

1.2、传统的Servlet API类型

HttpServletRequest

HttpSession

ServletContext

1.3、Struts2中将传统的Servlet API类型被处理成Map类型

访问更方便

不依赖传统Servlet API 类型--解耦合

二、ActionContext

所在包com.opensymphony.xwork2

ActionContext被称为Action上下文或者Action环境

ActionContext，提供每个Action运行时与之相关的所有信息

访问Servlet API

ActionContext类提供getContext（）方法获得实例

通过ActionContext类的实例可获得Map类型的请求，会话等

通过Put（）和Get（）方法在Map类型的对象中存取数据

二、简单例子

web.xml中添加

 <filter>        <filter-name>struts2</filter-name>        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPRepareAndExecuteFilter</filter-class>    </filter>    <filter-mapping>        <filter-name>struts2</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%    String path = request.getContextPath();    String basePath = request.getScheme() + "://"            + request.getServerName() + ":" + request.getServerPort()            + path + "/";%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><base href="<%=basePath %>>"><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登录页面</title></head><body><form action="user01.action" method="post"><table><tr><td>用户名:<input name="username"/></td></tr><tr><td>用户名:<input type="passWord" name="password"/></td></tr><tr><td><input type="submit" value="提交"/><input type="reset" value="重置"/></td></tr></table></form></body></html>

loginSuccess.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!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>登录成功页面</title></head><body><h1>jsp方式取值:</h1><%=request.getAttribute("linkaddress") %><br/><%=session.getAttribute("uname") %><br/><%=application.getAttribute("online") %><br/><h1>EL表达式取值:</h1>${request.linkaddress }<br/>${session.uname }<br/>${application.online }<br/><h1>struts取值:</h1><!-- 推荐使用这种 --><s:property value="#request.linkaddress"/><br/><!--  使用attr取值不推荐--><s:property value="#attr.linkaddress"/><br/><s:property value="#session.uname"/><br/><s:property value="#attr.uname"/><br/><s:property value="#application.online"/><br/><s:property value="#attr.online"/><br/><s:debug/></body></html>

UserAction3.java

package com.pb.web.action;import java.util.Map;import com.opensymphony.xwork2.ActionContext;import com.opensymphony.xwork2.ActionSupport;public class UserAction3 extends ActionSupport {        private String username;    private String password;    private Map<String , Object> request;    private Map<String , Object> session;    private Map<String , Object> application;        public String login(){        ActionContext ac=ActionContext.getContext();        request=(Map<String, Object>) ac.get("request");        session=ac.getSession();        application=ac.getApplication();        if(this.getUsername().equals("accp")&&this.getPassword().equals("accp")){            request.put("linkaddress", "这次的登录地点:SZ");            session.put("uname", username);            application.put("online", "当前在线人数：xxxx");            System.out.println(request.get("linkaddress"));            System.out.println(session.get("uname"));            System.out.println(application.get("online"));                        return SUCCESS;        }        return INPUT;                            }                public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    public Map<String, Object> getRequest() {        return request;    }    public void setRequest(Map<String, Object> request) {        this.request = request;    }    public Map<String, Object> getSession() {        return session;    }    public void setSession(Map<String, Object> session) {        this.session = session;    }    public Map<String, Object> getApplication() {        return application;    }    public void setApplication(Map<String, Object> application) {        this.application = application;    }        }

struts.xml

<struts>    <constant name="struts.enable.DynamicMethodInvocation" value="false" />    <constant name="struts.devMode" value="true" />    <package name="default" namespace="/" extends="struts-default">    <action name="user01" class="com.pb.web.action.UserAction3" method="login">    <result name="success">/loginSuccess.jsp</result>    <result name="input">/login.jsp</result>    </action>    </package></struts>

三、IOC方式获取Servlet API对象

更改以上的代码

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags" %><%    String path = request.getContextPath();    String basePath = request.getScheme() + "://"            + request.getServerName() + ":" + request.getServerPort()            + path + "/";%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><base href="<%=basePath %>>"><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>登录页面</title></head><body><!-- <form action="user01.action" method="post"> --><form action="user02.action" method="post"><table><tr><td>用户名:<input name="username"/></td></tr><tr><td>用户名:<input type="password" name="password"/></td></tr><tr><td><input type="submit" value="提交"/><input type="reset" value="重置"/></td></tr></table></form><s:property value="#session.msg"/></body></html>

loginSuccess.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="s" uri="/struts-tags"%><!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>登录成功页面</title></head><body><h1>jsp方式取值:</h1><%=request.getAttribute("linkaddress") %><br/><%=session.getAttribute("uname") %><br/><%=application.getAttribute("online") %><br/><h1>EL表达式取值:</h1>${request.linkaddress }<br/>${session.uname }<br/>${application.online }<br/><h1>struts取值:</h1><!-- 推荐使用这种 --><s:property value="#request.linkaddress"/><br/><!--  使用attr取值不推荐--><s:property value="#attr.linkaddress"/><br/><s:property value="#session.uname"/><br/><s:property value="#attr.uname"/><br/><s:property value="#application.online"/><br/><s:property value="#attr.online"/><br/><s:debug/></body></html>

UserAction2.java

package com.pb.web.action;import java.util.Map;import org.apache.struts2.interceptor.ApplicationAware;import org.apache.struts2.interceptor.RequestAware;import org.apache.struts2.interceptor.SessionAware;import com.opensymphony.xwork2.ActionSupport;public class UserAction2 extends ActionSupport implements RequestAware,        SessionAware, ApplicationAware {    private static final long serialVersionUID = 1L;    //属性要有getter、setter方法    private String username;    private String password;    //request,session,application不需要getter、setter方法    private Map<String , Object> request;    private Map<String , Object> session;    private Map<String , Object> application;        public String login(){                if(this.getUsername().equals("accp")&&this.getPassword().equals("accp")){            request.put("linkaddress", "这次的登录地点:SZ");            session.put("uname", username);            application.put("online", "当前在线人数：xxxx");            System.out.println(request.get("linkaddress"));            System.out.println(session.get("uname"));            System.out.println(application.get("online"));                        return SUCCESS;        }        session.put("msg", "用户名或者密码不正确！");        return INPUT;                            }        //使用struts2提供接口来生成application,session,request对象，    @Override    public void setApplication(Map<String, Object> application) {        this.application=application;    }    @Override    public void setSession(Map<String, Object> session) {        this.session=session;    }    @Override    public void setRequest(Map<String, Object> request) {        this.request=request;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }}

struts.xml

<action name="user02" class="com.pb.web.action.UserAction2" method="login">    <result name="success"  type="dispatcher">/loginSuccess.jsp</result>    <result name="input" type="redirect">/login.jsp</result>    </action>

使用传统的方式获取Servlet API

实现ServletRequestAware接口

package com.pb.web.action;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import org.apache.struts2.interceptor.ServletRequestAware;import org.apache.struts2.util.ServletContextAware;import com.opensymphony.xwork2.ActionSupport;public class UserAction04 extends ActionSupport implements ServletRequestAware,        ServletContextAware {    private String username;    private String password;    private HttpServletRequest request;    private HttpSession session;    private ServletContext application;    public String login() {        // 获取对象        session = request.getSession();        // 保存数据        request.setAttribute("loginAddress", "您本次登录地点是：北京");        session.setAttribute("username", username);        application.setAttribute("online", "当前在线人数：XXX");        // 获取数据        System.out.println(request.getAttribute("loginAddress"));        System.out.println(session.getAttribute("username"));        System.out.println(application.getAttribute("online"));        return SUCCESS;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    @Override    public void setServletRequest(HttpServletRequest request) {        this.request = request;    }    @Override    public void setServletContext(ServletContext application) {        this.application = application;    }}

或者使用时直接获取对象

package com.pb.web.action;import javax.servlet.ServletContext;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpSession;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class UserAction03 extends ActionSupport {    private String username;    private String password;    private HttpServletRequest request;    private HttpSession session;    private ServletContext application;    public String login() {        // 获取对象        request = ServletActionContext.getRequest();        session = request.getSession();        application = ServletActionContext.getServletContext();        // 保存数据        request.setAttribute("loginAddress", "您本次登录地点是：北京");        session.setAttribute("username",username);        application.setAttribute("online","当前在线人数：XXX");        // 获取数据        System.out.println(request.getAttribute("loginAddress"));        System.out.println(session.getAttribute("username"));        System.out.println(application.getAttribute("online"));        return SUCCESS;    }    public String getUsername() {        return username;    }    public void setUsername(String username) {        this.username = username;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }}

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