Struts2实现文件下载

淡淡的烟草味﹌ 2021-07-25 01:28 377阅读 0赞

**一 视图**

1 loginForm.jsp

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <%@ taglib prefix="s" uri="/struts-tags"%>
    <!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>
        <title>下载前的登录页面</title>
    </head>
    <body>
        <h3>下载前的登录页面</h3>
        <span style="color:red">${requestScope.tip}</span>
        <s:form action="login">
            <s:textfield name="user" label="用户名"/>
            <s:textfield name="pass" label="密码"/>
            <s:submit value="登录"/>
        </s:form>
    </body>
    </html>

2 struts2Down.jsp

<%@ page contentType="text/html; charset=GBK" language="java" errorPage="" %>
    <%@ taglib prefix="s" uri="/struts-tags"%>
    <!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>
        <title>Struts 2的文件下载</title>
    </head>
    <body>
        <h1>Struts 2的文件下载</h1>
        <ul>
        <li>
        下载疯狂Java联盟的Logo：
            <a href="download.action">下载图形文件</a>
        </li>
        <li>
        下载疯狂Java联盟的Logo的压缩文件：
            <a href="download2.action">下载压缩文件</a>
        </li>
        </ul>
    </body>
    </html>

**二 配置文件**

<?xml version="1.0" encoding="GBK"?>
    <!DOCTYPE struts PUBLIC
        "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
        "http://struts.apache.org/dtds/struts-2.3.dtd">
    <struts>
        
        <constant name="struts.i18n.encoding" value="GBK"/>
        <package name="lee" extends="struts-default">
            <action name="download" class="org.crazyit.app.action.FileDownloadAction">
            
                <param name="inputPath">/WEB-INF/images/疯狂联盟.jpg</param>
                
                <result type="stream">
                    
                    <param name="contentType">image/jpg</param>
                    
                    <param name="inputName">targetFile</param>
                    <param name="contentDisposition">filename="wjc_logo.jpg"</param>
                    
                    <param name="bufferSize">4096</param>
                </result>
            </action>
    
            <action name="download2" class="org.crazyit.app.action.AuthorityDownAction">
                
                <param name="inputPath">/WEB-INF/images/wjc_logo.zip</param>
                <result type="stream">
                    
                    <param name="contentType">application/zip</param>
                    
                    <param name="inputName">targetFile</param>
                    <param name="contentDisposition">filename="wjc_logo.zip"</param>
                    
                    <param name="bufferSize">4096</param>
                </result>
                
                 <result name="login">/WEB-INF/content/loginForm.jsp</result>
            </action>
    
            <action name="login" class="org.crazyit.app.action.LoginAction">
                <result>/WEB-INF/content/struts2Down.jsp</result>
            </action>
    
            <action name="*">
                <result>/WEB-INF/content/{1}.jsp</result>    
            </action>
    
        </package>
    </struts>

**三 过滤器**

1 LoginAction

package org.crazyit.app.action;
    
    import java.io.InputStream;
    import org.apache.struts2.ServletActionContext;
    import com.opensymphony.xwork2.Action;
    import com.opensymphony.xwork2.ActionContext;
    
    
    public class LoginAction implements Action
    {
        private String user;
        private String pass;
    
        // user的setter和getter方法
        public void setUser(String user)
        {
            this.user = user;
        }
        public String getUser()
        {
            return this.user;
        }
    
        // pass的setter和getter方法
        public void setPass(String pass)
        {
            this.pass = pass;
        }
        public String getPass()
        {
            return this.pass;
        }
    
        public String execute()
        {
            ActionContext.getContext().getSession()
                .put("user" , getUser());
            return SUCCESS;
        }
    }

2 AuthorityDownAction

package org.crazyit.app.action;
    
    import org.apache.struts2.ServletActionContext;
    import com.opensymphony.xwork2.*;
    
    import java.util.Map;
    import java.io.InputStream;
    
    public class AuthorityDownAction
        implements Action
    {
        private String inputPath;
        public void setInputPath(String value)
        {
            inputPath = value;
        }
    
        public InputStream getTargetFile() throws Exception
        {
            // ServletContext提供getResourceAsStream()方法
            // 返回指定文件对应的输入流
            return ServletActionContext.getServletContext()
                .getResourceAsStream(inputPath);
        }
    
        public String execute() throws Exception
        {
            // 取得ActionContext实例
            ActionContext ctx = ActionContext.getContext();
            // 通过ActionContext访问用户的HttpSession
            Map session = ctx.getSession();
            String user = (String)session.get("user");
            // 判断Session里的user是否通过检查
            if ( user !=  null && user.equals("crazyit.org"))
            {
                return SUCCESS;
            }
            ctx.put("tip", "您还没有登录，或者登录的用户名不正确，请重新登录！");
            return LOGIN;
        }
    }

3 FileDownloadAction

package org.crazyit.app.action;
    
    import java.io.InputStream;
    import org.apache.struts2.ServletActionContext;
    import com.opensymphony.xwork2.*;
    
    public class FileDownloadAction
        extends ActionSupport
    {
        // 该成员变量可以在配置文件中动态指定该值
        private String inputPath;
        // inputPath的setter方法
        public void setInputPath(String value)
        {
            inputPath = value;
        }
        /*
        定义一个返回InputStream的方法，
        该方法将作为被下载文件的入口，
        且需要配置stream类型结果时指定inputName参数，
        inputName参数的值就是方法去掉get前缀、首字母小写的字符串
        */
        public InputStream getTargetFile() throws Exception
        {
            // ServletContext提供getResourceAsStream()方法
            // 返回指定文件对应的输入流
            return ServletActionContext.getServletContext()
                .getResourceAsStream(inputPath);
        }
    }

**四 测试**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70]: /images/20210724/cd7466cbb3614ffe8c98055eb3826e5a.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 1]: /images/20210724/3effd59e7bc64330a682ada626df166e.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NoZW5ncWl1bWluZw_size_16_color_FFFFFF_t_70 2]: /images/20210724/dd0584a4af1f4064bf61d353ed815ed3.png