本篇文章给大家带来的内容是关于java如何使用fromdata实现文件上传（附代码），有一定的参考价值，有需要的朋友可以参考一下，希望对你有所帮助。
一、使用FromData将表单对象序列化后,使用request.getInputStream()来获取数据
1、表单代码如下
2、js的代码
<script>
function createXHR(){
return new XMLHttpRequest();
}
var sub = document.getElementById("sub");
sub.onclick=function(){
var xhr = createXHR();
var form = document.getElementById("user-info");//获取上边的表单
xhr.open("post","upload",true);
xhr.send(new FormData(form));
}
</script>
3、由于是序列化的表单所以java后端，不能使用request.getParameter()获取数据，需要使用request.getInputStream();获取数据
首先我们看到获取的数据
InputStream in = request.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String str = "";
while((str=br.readLine())!=null){
System.out.println(str);
}
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可以看到读取到这些数据
4、接着使用apache的上传文件框架进行上传
实现效果
以下是代码
package com.wangyang.servlet;
import java.io.File;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
@WebServlet("/upload")
public class Upload extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
/*
InputStream in = request.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String str = "";
while((str=br.readLine())!=null){
System.out.println(str);
}
*/
System.out.println("[-------------------------------------------------------]");
String filepath=request.getServletContext().getRealPath("/")+"upload/";
File file = new File(filepath);
if(!file.exists()) {
file.mkdir();
}
DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
try {
List<fileitem> items= upload.parseRequest(request);
for(FileItem item: items) {
System.out.println(filepath+item.getName());
if(!item.isFormField()) {
item.write(new File(filepath+item.getName()));
}
if(item.isFormField()){
System.out.println(item.getString());
System.out.println(item.getFieldName());
}
}
} catch (FileUploadException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
response.sendRedirect("index.jsp");
}
}</fileitem>
nbsp;html> <meta><meta><title>Insert title here</title><script> function createXHR(){ return new XMLHttpRequest(); } var sub = document.getElementById("sub"); sub.onclick=function(){ var xhr = createXHR(); var form = document.getElementById("user-info"); xhr.open("post","upload",true); xhr.send(new FormData(form)); } </script>
这里没有进行细节上的编程，只是为了说明简单原理
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