Spring MVC會(huì)根據(jù)請(qǐng)求方法的簽名不同，將請(qǐng)求消息中的信息以一定的方式轉(zhuǎn)換并綁定到請(qǐng)求方法的參數(shù)中胶坠。
1.文件上傳
文件上傳挂谍，必須將表單的method設(shè)置為POST叔壤，并將enctype設(shè)置為multipart/form-data。只有這樣口叙，才能將文件的二進(jìn)制數(shù)據(jù)發(fā)送給服務(wù)器炼绘。
Spring 3.0規(guī)范提供了方法來(lái)處理文件上傳，但是這種上傳需要在Servlet中完成妄田。而Spring MVC封裝了上傳功能俺亮，使用了Apache Commons FileUpload技術(shù)來(lái)實(shí)現(xiàn)了一個(gè)MultipartResolver實(shí)現(xiàn)類。
- Spring MVC依賴的組件包
compile group: 'commons-fileupload', name: 'commons-fileupload', version: '1.3.3'
- xml配置
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="maxUploadSize">
<value>10485760</value>
</property>
<property name="defaultEncoding">
<value>UTF-8</value>
</property>
</bean>
- 后臺(tái)代碼
新建上傳FileModel
public class FileDataModel implements Serializable {
private String filename;
private MultipartFile file;
public String getFilename() {
return filename;
}
public void setFilename(String filename) {
this.filename = filename;
}
public MultipartFile getFile() {
return file;
}
public void setFile(MultipartFile file) {
this.file = file;
}
}
Controller代碼
@Controller
@RequestMapping("file")
public class FileController {
@RequestMapping("upload")
public String upload() {
return "upload";
}
@RequestMapping(value = "upload", method = RequestMethod.POST)
public String uoload(FileDataModel fileDataModel, HttpServletRequest request, Model model) {
FileResult fileResult = new FileResult();
try {
if (fileDataModel.getFilename().isEmpty() || fileDataModel.getFile() == null)
throw new IllegalArgumentException("上傳文件名稱為空或者無(wú)上傳文件");
String filePath = request.getServletContext().getRealPath("/files");
String filename = fileDataModel.getFile().getOriginalFilename();
File savePath = new File(filePath, filename);
if (!savePath.getParentFile().exists())
savePath.getParentFile().mkdir();
fileDataModel.getFile().transferTo(new java.io.File(filePath + java.io.File.separator + filename));
fileResult.setTitle("上傳成功");
fileResult.setMessage("上傳成功");
fileResult.setSuccess(true);
} catch (Exception ex) {
fileResult.setTitle("上傳失斝瓮ァ铅辞！");
fileResult.setMessage(ex.getMessage());
}
model.addAttribute("fileResult", fileResult);
return "fileresult";
}
}
前臺(tái)JSP頁(yè)面
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Upload</title>
</head>
<body>
<form action="/file/upload" enctype="multipart/form-data" method="post">
<table>
<tr>
<td>文件描述：</td>
<td><input type="text" name="filename"/></td>
</tr>
<tr>
<td>請(qǐng)選擇文件：</td>
<td><input type="file" name="file"/></td>
</tr>
<tr>
<td>
<input type="submit" value="上傳"/>
</td>
</tr>
</table>
</form>
</body>
</html>
1.1Spring MVC的MultipartFile的常用方法
獲取文件數(shù)據(jù)
- 1.[] getBytes() throws IOException;
獲取文件的MIME類型，如image/jpeg等
- 2.String getContentType();
獲取文件流
- 3.InputStream getInputStream() throws IOException;
獲取表單中文件組件的名字
- 4.String getName();
獲取上傳文件的原名
- 5.String getOriginalFilename();
獲取文件的字節(jié)大小萨醒，單位為byte
- 6.long getSize();
是否有上傳的文件
- 7.boolean isEmpty();
將上傳文件保存到一個(gè)目標(biāo)文件中
- 8.void transferTo(File dest) throws IOException, IllegalStateException;
2.文件下載
Spring MVC提供了一個(gè)ResponseEntity類型斟珊，使用它可以很方便的定義返回的HttpHeader和HttpStatus
@RequestMapping("download")
public ResponseEntity<byte[]> download(HttpServletRequest request, @RequestParam("filename") String filename, Model model) {
ResponseEntity<byte[]> responseEntity = null;
try {
String path = request.getServletContext().getRealPath("/files");
String realPath = path + File.separator + filename;
File file = new File(realPath);
HttpHeaders headers = new HttpHeaders();
String downFileName = new String(filename.getBytes("UTF-8"), "iso-8859-1");
//通知瀏覽器以attachment（下載方式）打開圖片
headers.setContentDispositionFormData("attachment", downFileName);
//以二進(jìn)制流數(shù)據(jù)方式進(jìn)行下載
headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
responseEntity = new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file), headers, HttpStatus.CREATED);
} catch (Exception ex) {
ex.printStackTrace();
}
return responseEntity;
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>${requestScope.fileResult.title}</title>
</head>
<body>
<h1>${requestScope.fileResult.message}</h1><br/>
<a href="/file/download?filename=${requestScope.fileResult.fileName}">${requestScope.fileResult.fileName}</a>
</body>
</html>
3.攔截器
Interceptor攔截器是Spring MVC中相當(dāng)重要的功能，它的功能作用是攔截用戶的請(qǐng)求并進(jìn)行相對(duì)應(yīng)的處理富纸。比如通過(guò)攔截器進(jìn)行用戶權(quán)限驗(yàn)證囤踩，或者判斷用戶是否已經(jīng)登錄等。
Spring MVC 攔截器是可插拔式的設(shè)計(jì)晓褪。如果需要使用某個(gè)攔截器堵漱，只需要在配置文件中應(yīng)用攔截器即可。
3.1 HandlerInterceptor接口
Spring MVC中的Interceptor攔截器請(qǐng)求是通過(guò)實(shí)現(xiàn)HandlerInterceptor接口來(lái)完成的涣仿。
3.2實(shí)現(xiàn)攔截器
- 1.自定義類實(shí)現(xiàn)Spring的HandlerInterceptor接口
重要接口
該請(qǐng)求方法將在請(qǐng)求處理之前被調(diào)用勤庐。這個(gè)方法的作用是對(duì)進(jìn)行調(diào)用方法前進(jìn)行一些前置初始化操作，進(jìn)行判斷用戶請(qǐng)求是否可以進(jìn)行下去好港。當(dāng)方法返回false的時(shí)候愉镰，后續(xù)的Interceptor及Controller都不會(huì)繼續(xù)執(zhí)行。
boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception;
該方法是在perHandle返回true時(shí)钧汹，在調(diào)用目標(biāo)方法處理之后丈探，在返回視圖之前調(diào)用。這時(shí)候我們可以針對(duì)Controller處理之后的ModelAndView對(duì)象進(jìn)行操作拔莱。
void postHandle(
HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
throws Exception;
該方法是在整個(gè)請(qǐng)求處理結(jié)束之后碗降，也就是在DispatcherServlet渲染了對(duì)應(yīng)的視圖之后執(zhí)行。主要用于清理資源塘秦。
void afterCompletion(
HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception;
- 2.自定義類繼承HandlerInterceptorAdapter
代碼演示
- 實(shí)現(xiàn)HandlerInterceptor
public class AuthorizationInterceptor implements HandlerInterceptor {
/**
* 不攔截用戶登錄頁(yè)面及注冊(cè)頁(yè)面
*/
private static final String[] IGNORE_URI = {"user/login", "user/signup"};
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
boolean flag = false;
String servletPath = request.getServletPath();
for (String url : IGNORE_URI) {
if (servletPath.contains(url)) {
flag = true;
break;
}
}
if (!flag) {
User user = (User) request.getSession().getAttribute("user");
if (user == null) {
request.setAttribute("message", "請(qǐng)先登錄再訪問(wèn)網(wǎng)站");
request.getRequestDispatcher("user/login").forward(request, response);
} else
flag = true;
}
return flag;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
}
}
- xml配置
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/home/index"/>
<bean class="utils.AuthorizationInterceptor"/>
</mvc:interceptor>
</mvc:interceptors>
當(dāng)訪問(wèn)home/index的時(shí)候需要進(jìn)行驗(yàn)證
