struts 在Action中访问web元素（request，session等）

2022-11-14 20:44:43

出发jsp：

<?xml version="1.0" encoding="GB18030" ?>
<%@ page language="java" contentType="text/html; charset=GB18030"
pageEncoding="GB18030"%>

<% String context = request.getContextPath(); %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030" />
<title>Insert title here</title>
</head>
<body>
取得Map类型request,session,application,真实类型 HttpServletRequest, HttpSession, ServletContext的引用:
<ol>
    <li>前三者：依赖于容器</li>
    <li>前三者：IOC</li> (只用这种)
    <li>后三者：依赖于容器</li>
    <li>后三者：IOC</li>
</ol>
<br />
<form name="f" action="" method="post">
用户名：<input type="text" name="name"/>
密码：<input type="text" name="password"/>
<br />
<input type="button" value="submit1" onclick="javascript:document.f.action='login/login1';document.f.submit();" />
<input type="button" value="submit2" onclick="javascript:document.f.action='login/login2';document.f.submit();" />
<input type="button" value="submit3" onclick="javascript:document.f.action='login/login3';document.f.submit();" />
<input type="button" value="submit4" onclick="javascript:document.f.action='login/login4';document.f.submit();" />
</form>

</body>
</html>

struts配置文件：

<?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>
    <constant name="struts.devMode" value="true" />
    <package name="login" extends="struts-default" namespace="/login">
        <action name="login*" class="com.bjsxt.struts2.user.action.LoginAction{1}">
            <result>/user_login_success.jsp</result>
        </action>
    </package>
</struts>

四种方式的Action：

①

import java.util.Map;

import com.opensymphony.xwork2.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginAction1 extends ActionSupport {

    private Map request;
    private Map session;
    private Map application;

    public LoginAction1() {
        request = (Map)ActionContext.getContext().get("request");//static java.lang.ThreadLocal actionContext;
        session = ActionContext.getContext().getSession();
        application = ActionContext.getContext().getApplication();
    }

    public String execute() {
        request.put("r1", "r1");
        session.put("s1", "s1");
        application.put("a1", "a1");
        return SUCCESS;
    }
}

②（推荐方式）

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.ActionContext;
import com.opensymphony.xwork2.ActionSupport;

public class LoginAction2 extends ActionSupport implements RequestAware,SessionAware, ApplicationAware {

    private Map<String, Object> request;
    private Map<String, Object> session;
    private Map<String, Object> application;

    //DI dependency injection 称之为依赖注入
    //IoC inverse of control 或者控制反转
    public String execute() {
        request.put("r1", "r1");
        session.put("s1", "s1");
        application.put("a1", "a1");
        return SUCCESS;
    }

@Override
    public void setRequest(Map<String, Object> request) {
        this.request = request;
    }

@Override
    public void setSession(Map<String, Object> session) {
        this.session = session;
    }

@Override
    public void setApplication(Map<String, Object> application) {
        this.application = application;
    }


}

③

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 LoginAction3 extends ActionSupport {

    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;

    public LoginAction3() {
        request = ServletActionContext.getRequest();
        session = request.getSession();
        application = session.getServletContext();
    }

    public String execute() {
        request.setAttribute("r1", "r1");
        session.setAttribute("s1", "s1");
        application.setAttribute("a1", "a1");
        return SUCCESS;
    }

}

④

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts2.interceptor.ServletRequestAware;

import com.opensymphony.xwork2.ActionSupport;

public class LoginAction4 extends ActionSupport implements ServletRequestAware {

    private HttpServletRequest request;
    private HttpSession session;
    private ServletContext application;



    public String execute() {
        request.setAttribute("r1", "r1");
        session.setAttribute("s1", "s1");
        application.setAttribute("a1", "a1");
        return SUCCESS;
    }

@Override
    public void setServletRequest(HttpServletRequest request) {
        this.request = request;
        this.session = request.getSession();
        this.application = session.getServletContext();
    }

}

跳转到jsp：

<?xml version="1.0" encoding="GB18030" ?>
<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030"%>
    <%@taglib uri="/struts-tags" prefix="s" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030" />
<title>Insert title here</title>
</head>
<body>
    User Login Success!
    <br />
    <s:property value="#request.r1"/> | <%=request.getAttribute("r1") %> <br />
    <s:property value="#session.s1"/> | <%=session.getAttribute("s1") %> <br />
    <s:property value="#application.a1"/> | <%=application.getAttribute("a1") %> <br />
    <s:property value="#attr.a1"/><br />
    <s:property value="#attr.s1"/><br />
    <s:property value="#attr.r1"/><br />
    <s:debug></s:debug>
    <br />
</body>
</html>

标示符“#+key”，用于取context中的内容

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