SpringMVC实现文件下载功能
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2024-03-04 14:18:23
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...
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, 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;
}
}
编写视图
main.jsp
<%@ page contenttype="text/html;charset=utf-8" language="java" %> <html> <head> <title>downpage</title> </head> <body> <h4>点击链接下载文件</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>登录页面</title> </head> <body> <form:form commandname="login" action="login" method="post"> 账号: <br> <form:input path="username" csserrorclass="error" id="username"/> <br> 密码： <br> <form:input path="password" csserrorclass="error" id="password"/> <br> <input type="submit" value="提交"> </form:form> </body> </html>
案例2：阻止仅通过输入网址即可获取下载
@requestmapping(value = "/resource_download")
public string downloadresource(httpsession session, httpservletrequest request, httpservletresponse 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;
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。