struts2下载

最新推荐文章于 2023-02-09 00:09:46 发布

java_mail_test

最新推荐文章于 2023-02-09 00:09:46 发布

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分类专栏： Struts2 文章标签： Servlet XML Web JSP IE

本文链接：https://blog.youkuaiyun.com/java_mail_test/article/details/83525445

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本文介绍了一种使用Struts2框架实现文件下载的方法，包括XML配置、Action处理及自定义标签库和Servlet的设计，解决了中文文件名乱码及统一处理文件下载的问题。

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xml中配置

        <action name="download" class="com.test.DownloadTest">
            <param name="inputPath">/备忘.txt</param>
            <result name="success" type="stream">
                <param name="contentType">text/plain</param>
                <param name="inputName">targetFile</param>
                <param name="contentDisposition">attachment;filename="备忘文件.txt"</param>
                <param name="bufferSize">4096</param>
            </result>
        </action>

Action中代码

package com.test;

import java.io.InputStream;

import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;

public class DownloadTest extends ActionSupport {

	private static final long serialVersionUID = -2459892982073583733L;
	
	private String inputPath;

	public String execute() throws Exception {
		return SUCCESS;
	}
	
	public InputStream getTargetFile() throws Exception {
		return ServletActionContext.getServletContext().getResourceAsStream(inputPath);
	}
	public String getInputPath() {
		return inputPath;
	}

	public void setInputPath(String inputPath) {
		this.inputPath = inputPath;
	}

}

但是这样没有解决下载时候的保存文件名不是正确的文件名的问题。

而且每一个中文文件需要对应一个文件。很不方便。我自己设计了一个标签和一个servlet，专门处理这个问题，并且所有的文件不管在tomcat的web.xml中如何设置mime类型，都会弹出下载对话框，而不是应用相应的程序进行打开。

下面是标签库处理类

package com.tag;

import java.io.IOException;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.SimpleTagSupport;

public class MyJspTag extends SimpleTagSupport{

	private String url;
	
	private String display;
	
	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}
	
	public String getDisplay() {
		return display;
	}

	public void setDisplay(String display) {
		this.display = display;
	}

	@Override
	public void doTag() throws JspException, IOException {
		this.getJspContext().getOut().println("<a href=\"downloadServlet?path=" + url + "\">" + display + "</a>");
	}
	
}

下面是标签的tld文件

<?xml version="1.0" encoding="UTF-8" ?>

<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
    version="2.0">
    <tlib-version>1.0</tlib-version>
    <short-name>mytaglib</short-name>
	<uri>my-tag</uri>
	<tag>
		<name>downloadLink</name>
		<tag-class>com.tag.MyJspTag</tag-class>
		<body-content>empty</body-content>
		<attribute>
			<name>url</name>
			<required>true</required>
			<fragment>true</fragment>
		</attribute>
		
		<attribute>
			<name>display</name>
			<required>true</required>
			<fragment>true</fragment>
		</attribute>
	</tag>
</taglib>

下面是web.xml中对servlet的配置 , 需要将上述tld文件放置在web-inf文件夹下面

<servlet>
  	<servlet-name>downloadServlet</servlet-name>
  	<servlet-class>com.test.DownloadServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>downloadServlet</servlet-name>
  	<url-pattern>/downloadServlet</url-pattern>
  </servlet-mapping>

下面是Servlet的处理

package com.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;



public class DownloadServlet extends HttpServlet {

	private static final long serialVersionUID = 8438995458642112537L;

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String path = request.getParameter("path");
		if(path != null && !path.trim().equals("")) {
			path = new String(path.getBytes("iso-8859-1") , "utf-8");
			String realPath = request.getSession().getServletContext().getRealPath(path);
			File file = new File(realPath);
			if(file.exists() && file.isFile()) {
				InputStream in = null;
				try{
					in = new FileInputStream(realPath);
				}catch (Exception e) {
					PrintWriter pw = response.getWriter();
					pw.println("您请求的资源 " + path + " 不存在");
					pw.close();
					return;
				}
				String fileName = "";
				if(realPath.indexOf("\\") == -1) {
					fileName = realPath; 
				} else {
					fileName = realPath.substring(realPath.lastIndexOf("\\") + 1);
				}
				response.setHeader("Content-Disposition", "attachment; filename=" + new String(fileName.getBytes() , "iso-8859-1"));
				OutputStream out = response.getOutputStream();
				IOUtils.copy(in, out);
				IOUtils.closeQuietly(in);
				IOUtils.closeQuietly(out);
			} else {
				PrintWriter pw = response.getWriter();
				pw.println("您请求的资源 " + path + " 不是文件或文件不存在");
				pw.close();
				return;
			}
		} else {
			PrintWriter pw = response.getWriter();
			pw.println("错误的空资源");
			pw.close();
		}
	}
	
}

下面是jsp中怎样应用标签

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8"%>
<%@taglib prefix="mytag" uri="/WEB-INF/mytag.tld" %>
<!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>Insert title here</title>
</head>
<body>
    <mytag:downloadLink url="中文1.rar" display="中文1"/>
    <mytag:downloadLink url="中文2.txt" display="中文2"/>
</body>
</html>

显示的超链接是这样的。经测试在firefox和ie上基本能够正确处理下载问题。

<a
 href
="downloadServlet?path=%E4%B8%AD%E6%96%871.rar"
>中文1</a
>

	<a
 href
="downloadServlet?path=%E4%B8%AD%E6%96%872.txt"
>中文2</a
>