java檔案上傳下載
這裡先說下spring mvc 遇到的坑，就是如果檔案上傳時，後端這樣寫public String file1(HttpServletRequest request)，根據request拿到的東西是空的。所以要下面這樣寫。
上傳
在任何xml裡面（因為都要載入到的，所以可以隨便放進去）加上
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="UTF-8"></property>
<property name="maxUploadSize" value="10485760" />
cotroller裡面
@RequestMapping(value="file",method=RequestMethod.POST)
public String file1(@RequestParam("file")MultipartFile file1,HttpServletRequest request) throws IOException {
InputStream inputStream=file1.getInputStream();
//System.out.println(file1.getOriginalFilename()+" "+file1.getSize());
//第一種是原始的java檔案上傳的方式，下載的話也跟這個差不多，所以下載就不寫了；
String name=request.getSession().getServletContext().getRealPath("/")+"file";
System.out.println(name);
File file0=new File(name);
if(!file0.isDirectory()&&!file0.exists())
file0.mkdir();
name+="\\"+file1.getOriginalFilename();
File file=new File(name);
try {
file.createNewFile();
FileOutputStream outputStream;
outputStream = new FileOutputStream(file);
byte b[]=new byte[1024];
int n;
while((n=inputStream.read(b))!=-1){
outputStream.write(b, 0, n);
}
outputStream.close();
inputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
//下面是xml引入的bean,也是比較方便的方法
/*
if(!file.isEmpty()){
try {
//這裡將上傳得到的檔案儲存至 d:\\temp\\file 目錄
FileUtils.copyInputStreamToFile(file.getInputStream(), new File("d:/hello",
System.currentTimeMillis()+ file.getOriginalFilename()));
} catch (IOException e) {
e.printStackTrace();
}
}
*/
return "upload";
}
檔案下載一般會涉及特定資料夾下的搜尋檔案（用迭代方法）
import java.io.File;
public class test {
public static void main(String[] args) {
String path="D:/hello/";
File file=new File(path);
researchfile(file);
}
public static void researchfile(File file) {
if (file.isDirectory()) {
File[] filearry = file.listFiles();
for (File f : filearry) {
if (f.isDirectory()) {
// System.out.println("0"+f.getAbsoluteFile());
} else {
System.out.println(f.getAbsoluteFile());
}
researchfile(f);
}
}
}
}
2018-1-17
有更好更方便的上傳方式，如下：
@RequestMapping(value = "fileupload")
@ResponseBody
public boolean fileupload(@RequestParam(value = "filename")MultipartFile file){
if(file.isEmpty()){
return false;
}
String name=file.getOriginalFilename();
int Size= (int) file.getSize();
System.out.println(name + "-->" + Size);
String path="D:/NewFile";
File f=new File(path+"/"+name);
if(!f.getParentFile().exists()){
f.getParentFile().mkdir();
}
try {
file.transferTo(f); //儲存檔案
return true;
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
}然後上面都是寫一個檔案上傳時的controller，下面寫一個多檔案上傳的
/**
* 實現多檔案上傳
* */
@RequestMapping(value="multifileUpload",method= RequestMethod.POST)
public @ResponseBody boolean multifileUpload(@RequestParam(value = "filename")List<MultipartFile> files){
if(files.isEmpty()){
System.out.println("檔案為空");
return false;
}
String path = "D:/NewFile" ;
for(MultipartFile file:files){
String fileName = file.getOriginalFilename();
int size = (int) file.getSize();
System.out.println(fileName + "-->" + size);
if(file.isEmpty()){
return false;
}else{
File dest = new File(path + "/" + fileName);
if(!dest.getParentFile().exists()){ //判斷檔案父目錄是否存在
dest.getParentFile().mkdir();
}
try {
file.transferTo(dest);
}catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
return false;
}
}
}
return true;
}下載
下載的程式碼貼上下別人的，供參考
@RequestMapping("download")
public String downLoad(HttpServletResponse response) throws UnsupportedEncodingException {
String filename="報名照片.jpg";
String filePath = "D:/NewFile" ;
File file = new File(filePath + "/" + filename);
if(file.exists()){ //判斷檔案父目錄是否存在
response.setContentType("application/force-download");
response.setHeader("Content-Disposition", "attachment;fileName=" + new String("報名照片.jpg".getBytes("gb2312"),"ISO_8859_1"));
byte[] buffer = new byte[1024];
FileInputStream fis = null; //檔案輸入流
BufferedInputStream bis = null;
OutputStream os = null; //輸出流
try {
os = response.getOutputStream();
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
int i = bis.read(buffer);
while(i != -1){
os.write(buffer);
i = bis.read(buffer);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("----------file download" + filename);
try {
bis.close();
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return null;
}