SpringMVC实现文件下载功能

SpringMVC实现文件下载功能

本文实例为大家分享了SpringMVC文件下载的具体代码，供大家参考，具体内容如下

两个案例

1.为登录用户提供下载服务。

2.阻止仅通过输入网址即可获取下载。

文件下载概览

为了将文件发送给浏览器，我们需要在控制器中完成以下操作：

对请求处理方法使用void返回类型，并且在方法中添加HttpServletResponse参数。

将响应的内容类型设为文件的内容类型。Content-Type标题在某个实体的body中定义数据的类型，并包含媒体类型和子类型标识符。如果不清楚内容类型，并且希望浏览器失始终显示保存对话框，则将它设为APPLICATION/OCTET-STREAM。这个值时不区分大小写的。

添加一个名为Content-Disposition的HTTP响应标题，并赋值attachment;filename=fileName，这里的fileName是默认的文件名。

案例1：为登录用户提供下载服务

Domain类

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, HttpServletResponshttp://e 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;

}

}

编写视图

Main.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

Down

LoginForm.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

账号:

密码：

案例2：阻止仅通过输入网址即可获取下载

@RequestMapping(value = "/resource_download")

public String downloadResource(HttpSession session, HttpServletRequest request, Hhttp://ttpServletResponse response,@RequestHeader String refuer

){

if(refer==null) //通过判断refer来浏览器输入网址就能下载图片的情况

{

　　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;

}

}

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