为了将像文件这样的资源发送到浏览器，需要在控制器完成以下工作：
- 对请求处理方法使用void返回类型，并在方法中添加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。如果不清楚类型，并希望浏览器始终显示Save As对话框，则将它设为APPLICATION/OCTET-STREAM。不区分大小写。
- 添加一个名为Content-Disposition的HTTP响应标题，并赋值attachment；filaname=fileName,这里的fileName是默认文件名，应该出现在FileDownload(文件下载)对话框中。
为防止交叉引用，使用referer，当包含你的域名时才发出资源。不能严格防范，但获取资源不那么容易了。
- controller
package com.company.combine.controller;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import com.company.combine.model.User;
import org.apache.commons.logging.Log;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.multipart.MultipartFile;
import com.mysql.jdbc.log.LogFactory;
@Controller
public class ResourceController {
private static final Log logger = org.apache.commons.logging.LogFactory.getLog(ResourceController.class);
@RequestMapping(value = "/login1")
public String login(@ModelAttribute User user, HttpSession session, Model model){
model.addAttribute("login1", new User());
if("username".equals(user.getUsername())&&"password".equals(user.getPassword())){
session.setAttribute("loggedIn", Boolean.TRUE);
return "Main";
}else{
return "LoginForm";
}
}
@RequestMapping(value = "/resource_download")
public String saveProduct(HttpServletRequest request,
HttpSession session, HttpServletResponse response, @RequestHeader String referer){
if(session == null || session.getAttribute("loggedIn")==null){
return "LoginForm";
}
if (referer == null||!referer.contains("mydomain")) {//检查是否包含自己的域名
return null;
}
String dataDirectory = request.getServletContext().getRealPath("/WEB-INF/data");
File file = new File(dataDirectory,"GreenDao3.pdf");
System.out.println("file.getAbsolutePath():"+file.getAbsolutePath());
if(file.exists()){
response.setContentType("application/pdf");
response.addHeader("Content-Disposition", "attachment;filename=GreenDao3.pdf");
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,0,1);
i = bis.read(buffer);
}
} catch (Exception e) {
// TODO: handle exception
}finally {
if(bis != null){
try {
bis.close();
} catch (Exception e2) {
// TODO: handle exception
}
}
if(fis !=null){
try {
fis.close();
} catch (Exception e2) {
// TODO: handle exception
}
}
}
}
return null;
}
}
- LoginForm.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="GB2312"%>
<%@taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<!DOCTYPE html >
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登录</title>
</head>
<body>
<div id="global">
<form:form action="/login1" method="post"
commandName="user">
<fieldset>
<legend>Login</legend>
<p>
<label for="userName">UserName:</label>
<form:input id="username" path="username" cssErrorClass="error" />
</p>
<p>
<label for="password">Password:</label>
<form:input id="password" path="password" cssErrorClass="error" />
</p>
<p id="buttons">
<input id="reset" type="reset" tabindex="4">
<input id="submit" type="submit" tabindex="5" value="Login">
</p>
</fieldset>
</form:form>
</div>
</body>
</html>
- main.jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="GB2312"%>
<%@taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<!DOCTYPE html >
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>登录</title>
</head>
<body>
<div id="global">
<h4>Please click the link below.</h4>
<p>
<a href="resource_download">Download</a>
</p>
</div>
</body>
</html>
- 注意在/WEB-INF/data下放置下载文件
