java web文件上传与下载

jsp代码（文件上传）
   
   

   
   
<form id="upLoad" method="post">
<input type="file" id="yaFile" name="file"> <br/>
<input id="fileSubmit" type="button" value="提交">
</form>
   
   

js代码：这里我选择的是异步提交
   
   

   
   
$("#fileSubmit").click(function(){
var formData = new FormData();
formData.append("file", document.getElementById("upLoad").files[0]);
$.ajax({
cache: true,
type: "POST",
url:'路径',
data:formData,
processData: false, //禁止jquery对DAta数据的处理,默认会处理
contentType: false, //禁止设置请求类型
async: false,
error: function(request) {
alert("上传失败");
},
success: function(data) {
if(data==0){
   
   

                        alert("上传成功");
   
   

} } });});

java代码：文件上传
   
   

   
   
/**
* 文件上传功能
* @param file
* @return
* @throws IOException
*/
@RequestMapping( "/upload")
@ResponseBody
public String upload(MultipartFile file,String faUrl,HttpServletRequest request) throws IOException{
String path = request.getSession().getServletContext().getRealPath( "upload"); //文件上传路径
String fileName = file.getOriginalFilename();
File dir = new File(path ,fileName);
if(!dir.exists()){
dir.mkdirs();
}
//MultipartFile自带的解析方法
file.transferTo(dir);
return "0";
}
   
   

js代码：文件下载
   
   

   
   
function onClick() {
var url ="路径"
document.location.href=url;
}
   
   

java代码：文件下载
   
   

   
   
/**
* 文件下载功能
* @param request
* @param response
* @throws Exception
*/
@RequestMapping( "/fileDown")
@ResponseBody
public void fileDown(HttpServletRequest request,HttpServletResponse response){
//通过文件名找出文件的所在目录
String path = request.getSession().getServletContext().getRealPath( "upload");
ServletOutputStream out;
//得到要下载的文件
File file = new File(path);
try {
//设置响应头，控制浏览器下载该文件
response.setContentType( "multipart/form-data");
//获得浏览器信息,并处理文件名
String headerType=request.getHeader( "User-Agent").toUpperCase();
String fileName = null;
if (headerType.indexOf( "EDGE") > 0||headerType.indexOf( "MSIE")> 0||headerType.indexOf( "GECKO")> 0) {
fileName=URLEncoder.encode(file.getName(), "UTF-8");
} else{
fileName= new String(file.getName().replaceAll( " ", "").getBytes( "utf-8"), "iso8859-1");
}
response.addHeader( "Content-Disposition", "attachment;filename="+fileName);
response.addHeader( "Content-Length", "" + file.length());
FileInputStream inputStream = new FileInputStream(file);

out = response.getOutputStream();

int b = 0;
byte[] buffer = new byte[ 1024];
while (b != - 1) {
b = inputStream.read(buffer);
//写到输出流(out)中
if(b!=- 1)
out.write(buffer, 0, b);
}
inputStream.close();
out.close(); //关闭输出流
out.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
   
   

以上为文件上传、文件下载的全部代码。