前端使用form表单提交图片后，java后台怎么获取该图片？

上传图片 后台获取的时候直接从数据库拿路径
下面这是servlet的内容：
package demo;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
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.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

public class DemoServlet extends HttpServlet {

private static final String UPLOAD_DIRECTORY = "upload";
private static final int MEMORY_THRESHOLD = 1024 * 1024 * 3; // 3MB
private static final int MAX_FILE_SIZE = 1024 * 1024 * 40; // 40MB
private static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50; // 50MB

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
DiskFileItemFactory factory=new DiskFileItemFactory();
ServletFileUpload sfu=new ServletFileUpload(factory);
sfu.setHeaderEncoding("UTF-8");
sfu.setProgressListener(new ProgressListener() {

public void update(long pBytesRead, long pContentLength, int pItems) {
System.out.println("文件大小为："+pContentLength+",当前已处理："+pBytesRead);

}
});
//判断提交上来的数据是否是上传表单的数据
if(!ServletFileUpload.isMultipartContent(request)){
PrintWriter writer= response.getWriter();
writer.println("Error:表单必须包含 enctype=multipart/form-data");
writer.flush();
return;
}
factory.setSizeThreshold(MEMORY_THRESHOLD);
//设置临时储存目录
factory.setRepository(new File(System.getProperty("java.io.tmpdir")));
//设置最大文件上传值
sfu.setFileSizeMax(MAX_FILE_SIZE);
//设置最大请求值（包含文件和表单数据）
sfu.setSizeMax(MAX_REQUEST_SIZE);
String uploadpath=getServletContext().getRealPath("./")+ File.separator+UPLOAD_DIRECTORY;
File file=new File(uploadpath);
if(!file.exists()){
file.mkdir();
}

try {
List formItems = sfu.parseRequest(request);
if(formItems!=null&&formItems.size()>0){
for(FileItem item:formItems){
if(!item.isFormField()){
String fileName=new File(item.getName()).getName();
String filePath=uploadpath+File.separator+fileName;
File storeFile=new File(filePath);
System.out.println(filePath);
item.write(storeFile);
request.setAttribute("message", "文件上传成功！");
}
}
}
} catch (Exception e) {
request.setAttribute("message", "错误信息："+e.getMessage());
}
getServletContext().getRequestDispatcher("/demo.jsp").forward(request, response);
}

}

下面是jsp的内容，jsp放到webapp下，如果想放到WEB-INF下就把servlet里转发的路径改一下：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>

首先在html的form添加:enctype="multipart/form-data"

// Java代码
@RequestMapping("/upload"   )  
    public String addUser(@RequestParam("file") CommonsMultipartFile[] files,HttpServletRequest request){  
          
        for(int i = 0;i            System.out.println("fileName---------->" + files[i].getOriginalFilename());  
          
            if(!files[i].isEmpty()){  
                int pre = (int) System.currentTimeMillis();  
                try {  
                    //拿到输出流，同时重命名上传的文件  
                    FileOutputStream os = new FileOutputStream("H:/" + new Date().getTime() + files[i].getOriginalFilename());  
                    //拿到上传文件的输入流  
                    FileInputStream in = (FileInputStream) files[i].getInputStream();  
                      
                    //以写字节的方式写文件  
                    int b = 0;  
                    while((b=in.read()) != -1){  
                        os.write(b);  
                    }  
                    os.flush();  
                    os.close();  
                    in.close();  
                    int finaltime = (int) System.currentTimeMillis();  
                    System.out.println(finaltime - pre);  
                      
                } catch (Exception e) {  
                    e.printStackTrace();  
                    System.out.println("上传出错");  
                }  
        }  
        }  
        return "/success";  
    }

图片要使用文件上传的方式。既然你使用spring框架的话，那就用它本身的上传配置。
你在spring配置文件中加上这个：
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">



//后台

public String addUser(@RequestParam("file") MultipartFile myfile,HttpServletRequest request) throws IOException{

//下面这个方法可以实现文件上传到服务器
//不懂的话可以查下spring API

FileUtils.copyInputStreamToFile(myfile.getInputStream(), new File(realPath, myfile.getOriginalFilename()));
}

不是有方法获取吗，好多年不写给忘了。