SpringMVC實現(xiàn)文件下載功能

更新時間：2017年03月09日 11:38:17 作者：MrSaber

這篇文章主要為大家詳細介紹了SpringMVC實現(xiàn)文件下載功能，具有一定的參考價值，感興趣的小伙伴們可以參考一下

本文實例為大家分享了SpringMVC文件下載的具體代碼，供大家參考，具體內(nèi)容如下

兩個案例

　　1.為登錄用戶提供下載服務(wù)。

　　2.阻止僅通過輸入網(wǎng)址即可獲取下載。

文件下載概覽

　　為了將文件發(fā)送給瀏覽器，我們需要在控制器中完成以下操作：

對請求處理方法使用void返回類型，并且在方法中添加HttpServletResponse參數(shù)。
將響應(yīng)的內(nèi)容類型設(shè)為文件的內(nèi)容類型。Content-Type標(biāo)題在某個實體的body中定義數(shù)據(jù)的類型，并包含媒體類型和子類型標(biāo)識符。如果不清楚內(nèi)容類型，并且希望瀏覽器失始終顯示保存對話框，則將它設(shè)為APPLICATION/OCTET-STREAM。這個值時不區(qū)分大小寫的。
添加一個名為Content-Disposition的HTTP響應(yīng)標(biāo)題，并賦值attachment;filename=fileName，這里的fileName是默認的文件名。

案例1：為登錄用戶提供下載服務(wù)

Domain類

package domain;
public class Login {
 private String username;
 private String password;

 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;
 }
}

Controller控制器

package controller;

import domain.Login;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.*;

@Controller
public class ResourceController {
 private static final Log logger = LogFactory.getLog(ResourceController.class);

 @RequestMapping(value = "/login")
 public String login(@ModelAttribute Login login, HttpSession session, Model model)
 {
  model.addAttribute("login",new Login());
  if("ms".equals(login.getUsername())&&"123".equals(login.getPassword()))
  {
   session.setAttribute("loggedIn",Boolean.TRUE);
   return "Main";
  }
  else
  {
   return "LoginForm";
  }
 }

 @RequestMapping(value = "/resource_download")
 public String downloadResource(HttpSession session, HttpServletRequest request, HttpServletResponse response)
 {
  if(session==null||session.getAttribute("loggedIn")==null)
  {
  return "LoginForm";
  }
  String dataDirectory = request.getServletContext().getRealPath("/WEB-INF/data");
  File file = new File(dataDirectory,"Blog.zip");
  if(file.exists())
  {
   response.setContentType("application/octet-stream");
   response.addHeader("Content-Disposition","attachment;filename=Blog.zip");
   byte[] buffer = new byte[1024];
   FileInputStream fis =null;
   BufferedInputStream bis =null;
   try {
    fis = new FileInputStream(file);
    bis = new BufferedInputStream(fis);
    OutputStream os =response.getOutputStream();
    int i =bis.read(buffer);
    while (i!=-1) {
     os.write(buffer, 0, i);
     i=bis.read(buffer);
    }
   } catch (FileNotFoundException e) {
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   }finally {
    try {
     bis.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
    try {
     fis.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }

  }
  return null;
 }
}

編寫視圖

Main.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
 <title>DownPage</title>
</head>
<body>
 <h4>點擊鏈接下載文件</h4>
 <p>
  <a href="resource_download" rel="external nofollow" >Down</a>
 </p>
</body>
</html>

LoginForm.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
 <title>登錄頁面</title>
</head>
<body>
 <form:form commandName="login" action="login" method="post">
  賬號: <br>
  <form:input path="username" cssErrorClass="error" id="username"/>
  <br> 密碼： <br>
  <form:input path="password" cssErrorClass="error" id="password"/>
  <br> <input type="submit" value="提交">
 </form:form>
</body>
</html>

案例2：阻止僅通過輸入網(wǎng)址即可獲取下載

 @RequestMapping(value = "/resource_download")
 public String downloadResource(HttpSession session, HttpServletRequest request, HttpServletResponse response,@RequestHeader String refuer
 ){
  if(refer==null) //通過判斷refer來瀏覽器輸入網(wǎng)址就能下載圖片的情況
  {
  　　return "LoginForm";
  }
  String dataDirectory = request.getServletContext().getRealPath("/WEB-INF/data");
  File file = new File(dataDirectory,"Blog.zip");
  if(file.exists())
  {
   response.setContentType("application/octet-stream");
   response.addHeader("Content-Disposition","attachment;filename=Blog.zip");
   byte[] buffer = new byte[1024];
   FileInputStream fis =null;
   BufferedInputStream bis =null;
   try {
    fis = new FileInputStream(file);
    bis = new BufferedInputStream(fis);
    OutputStream os =response.getOutputStream();
    int i =bis.read(buffer);
    while (i!=-1) {
     os.write(buffer, 0, i);
     i=bis.read(buffer);
    }
   } catch (FileNotFoundException e) {
    e.printStackTrace();
   } catch (IOException e) {
    e.printStackTrace();
   }finally {
    try {
     bis.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
    try {
     fis.close();
    } catch (IOException e) {
     e.printStackTrace();
    }
   }

  }
  return null;
 }
}

以上就是本文的全部內(nèi)容，希望對大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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