【笔记】Spring MVC学习指南（十二）下载文件
2015-10-06 23:37
856 查看
《SpringMVC学习指南》的最终章。
这章主要讲的文件下载，更多的是指如何绕过直接下载，通过验证获取文件。
先来看第一部分，如何通过验证才能获取文件（配置文件那部分，没有新的内容，就不贴出来了）：
package app12a.controller;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
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 app12a.domain.Login;
@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());
// 硬编码，也只有在演示时才会这么做，实际工作中，这么做，是要被骂惨的o_O
if ("paul".equals(login.getUserName()) && "secret".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, "secret.pdf");
if (file.exists()) {
// 接下来的两行代码，对于实现弹窗下载，是标准代码，记住！！！
response.setContentType("application/pdf"); // 如果不清楚内容类型，可以改为"application/octet-stream"，不区分大小写
response.addHeader("Content-Disposition", "attachment; filename=secret.pdf"); // filename为弹窗时显示的名称
// 接下来的代码也可以当模板对待，记住没坏处！！！
byte[] buffer = new byte[1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
// if using Java 7, use try-with-resources
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 (IOException ex) {
// do something,
// probably forward to an Error page
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
}
}
}
}
return null;
}
}
其实就是很简单的那么回事，最重要的知识点，感觉还是response.setContentType()和response.addHeader()。
接下来还有一部分讲解了如何防止交叉引用，简单地说，就是防止别人盗用你的资源，做到只有当referer标题中包含你的域名时才发出资源。
package app12a.controller;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class ImageController {
private static final Log logger = LogFactory.getLog(ImageController.class);
@RequestMapping(value = "/image_get/{id}", method = RequestMethod.GET)
public void getImage(@PathVariable String id, HttpServletRequest request, HttpServletResponse response, @RequestHeader String referer) { // @RequestHeader String referer 唯一知识点
if (referer != null) {
String imageDirectory = request.getServletContext().getRealPath("/WEB-INF/image");
File file = new File(imageDirectory, id + ".jpg");
if (file.exists()) {
response.setContentType("image/jpg");
byte[] buffer = new byte[1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
// if you're using Java 7, use try-with-resources
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 (IOException ex) {
// do something here
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
}
}
}
}
}
}
}
运行截图：
至此，《SpringMVC学习指南》的正文部分就结束了，毫无疑问，都是最基础的知识点，不过入门了，再学深的知识点，会快得多！！
这章主要讲的文件下载，更多的是指如何绕过直接下载，通过验证获取文件。
先来看第一部分，如何通过验证才能获取文件（配置文件那部分，没有新的内容，就不贴出来了）：
package app12a.controller;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
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 app12a.domain.Login;
@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());
// 硬编码，也只有在演示时才会这么做，实际工作中，这么做，是要被骂惨的o_O
if ("paul".equals(login.getUserName()) && "secret".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, "secret.pdf");
if (file.exists()) {
// 接下来的两行代码，对于实现弹窗下载，是标准代码，记住！！！
response.setContentType("application/pdf"); // 如果不清楚内容类型，可以改为"application/octet-stream"，不区分大小写
response.addHeader("Content-Disposition", "attachment; filename=secret.pdf"); // filename为弹窗时显示的名称
// 接下来的代码也可以当模板对待，记住没坏处！！！
byte[] buffer = new byte[1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
// if using Java 7, use try-with-resources
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 (IOException ex) {
// do something,
// probably forward to an Error page
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
}
}
}
}
return null;
}
}
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML>
<html>
<head>
<title>Login</title>
<style type="text/css">@import url("<c:url value="/css/main.css"/>");</style>
</head>
<body>
<div id="global">
<form:form commandName="login" action="login" method="post">
<fieldset>
<legend>Login</legend>
<p>
<label for="userName">User Name: </label>
<form:input id="userName" path="userName" cssErrorClass="error"/>
</p>
<p>
<label for="password">Password: </label>
<form:password 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>其实就是很简单的那么回事，最重要的知识点，感觉还是response.setContentType()和response.addHeader()。
接下来还有一部分讲解了如何防止交叉引用，简单地说，就是防止别人盗用你的资源，做到只有当referer标题中包含你的域名时才发出资源。
package app12a.controller;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class ImageController {
private static final Log logger = LogFactory.getLog(ImageController.class);
@RequestMapping(value = "/image_get/{id}", method = RequestMethod.GET)
public void getImage(@PathVariable String id, HttpServletRequest request, HttpServletResponse response, @RequestHeader String referer) { // @RequestHeader String referer 唯一知识点
if (referer != null) {
String imageDirectory = request.getServletContext().getRealPath("/WEB-INF/image");
File file = new File(imageDirectory, id + ".jpg");
if (file.exists()) {
response.setContentType("image/jpg");
byte[] buffer = new byte[1024];
FileInputStream fis = null;
BufferedInputStream bis = null;
// if you're using Java 7, use try-with-resources
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 (IOException ex) {
// do something here
} finally {
if (bis != null) {
try {
bis.close();
} catch (IOException e) {
}
}
if (fis != null) {
try {
fis.close();
} catch (IOException e) {
}
}
}
}
}
}
}
运行截图：
至此，《SpringMVC学习指南》的正文部分就结束了，毫无疑问，都是最基础的知识点，不过入门了，再学深的知识点，会快得多！！
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