Struts2(八)訪問Servlet API

時間 2019-11-18

標籤 struts2 struts 訪問 servlet api 欄目 Struts 简体版

原文原文鏈接

1、Struts2中的Servlet API

1.一、struts2的Action實現了MVC中C層的做用

針對請求用戶顯示不一樣的信息html

登陸後段保存用戶信息 ----sessionjava

保存當前在線人數等功能---applicationweb

1.二、傳統的Servlet API類型

HttpServletRequestapache

HttpSessionsession

ServletContextapp

1.三、Struts2中將傳統的Servlet API類型被處理成Map類型

訪問更方便jsp

不依賴傳統Servlet API 類型--解耦合ide

2、ActionContext

所在包com.opensymphony.xwork2post

ActionContext被稱爲Action上下文或者Action環境ui

ActionContext，提供每一個Action運行時與之相關的全部信息

訪問Servlet API

ActionContext類提供getContext（）方法得到實例

經過ActionContext類的實例可得到Map類型的請求，會話等

經過Put（）和Get（）方法在Map類型的對象中存取數據

2、簡單例子

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>登陸頁面</title>
</head>
<body>
<form action="user01.action" method="post">
<table>
<tr>
<td>用戶名:<input name="username"/></td>
</tr>
<tr>
<td>用戶名:<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>登陸成功頁面</title>
</head>
<body>
<h1>jsp方式取值:</h1>
<%=request.getAttribute("linkaddress") %><br/>
<%=session.getAttribute("uname") %><br/>
<%=application.getAttribute("online") %><br/>
<h1>EL表達式取值:</h1>
${request.linkaddress }<br/>
${session.uname }<br/>
${application.online }<br/>
<h1>struts取值:</h1>
<!-- 推薦使用這種 -->
<s:property value="#request.linkaddress"/><br/>
<!--  使用attr取值不推薦-->
<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", "此次的登陸地點:SZ");
            session.put("uname", username);
            application.put("online", "當前在線人數：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>

3、IOC方式獲取Servlet API對象

更改以上的代碼

<%@ 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>登陸頁面</title>
</head>
<body>
<!-- <form action="user01.action" method="post"> -->
<form action="user02.action" method="post">
<table>
<tr>
<td>用戶名:<input name="username"/></td>
</tr>
<tr>
<td>用戶名:<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>登陸成功頁面</title>
</head>
<body>
<h1>jsp方式取值:</h1>
<%=request.getAttribute("linkaddress") %><br/>
<%=session.getAttribute("uname") %><br/>
<%=application.getAttribute("online") %><br/>
<h1>EL表達式取值:</h1>
${request.linkaddress }<br/>
${session.uname }<br/>
${application.online }<br/>
<h1>struts取值:</h1>
<!-- 推薦使用這種 -->
<s:property value="#request.linkaddress"/><br/>
<!--  使用attr取值不推薦-->
<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;
    //屬性要有getter、setter方法
    private String username;
    private String password;
    //request,session,application不須要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", "此次的登陸地點:SZ");
            session.put("uname", username);
            application.put("online", "當前在線人數：xxxx");
            System.out.println(request.get("linkaddress"));
            System.out.println(session.get("uname"));
            System.out.println(application.get("online"));
            
            return SUCCESS;
        }
        session.put("msg", "用戶名或者密碼不正確！");
        return INPUT;
        
        
        
    }
    
    //使用struts2提供接口來生成application,session,request對象，
    @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>

使用傳統的方式獲取Servlet API

實現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() {
        // 獲取對象
        session = request.getSession();
        // 保存數據
        request.setAttribute("loginAddress", "您本次登陸地點是：北京");
        session.setAttribute("username", username);
        application.setAttribute("online", "當前在線人數：XXX");
        // 獲取數據
        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;

    }

}

或者使用時直接獲取對象

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() {
        // 獲取對象
        request = ServletActionContext.getRequest();
        session = request.getSession();
        application = ServletActionContext.getServletContext();
        // 保存數據
        request.setAttribute("loginAddress", "您本次登陸地點是：北京");
        session.setAttribute("username",username);
        application.setAttribute("online","當前在線人數：XXX");
        // 獲取數據
        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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