基于servlet的文件上传

import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; 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; import org.apache.commons.io.FileUtils;

/**  * Servlet implementation class uploadservlet  */ @WebServlet("/upload") public class uploadservlet extends HttpServlet {

@Override protected void service(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {  // TODO Auto-generated method stub  String mess="";  //上传位置目标路径   String basePath="D://upload";   //创建工厂，   DiskFileItemFactory dfIF=new DiskFileItemFactory();   //   ServletFileUpload sf=new ServletFileUpload(dfIF);   //   sf.setHeaderEncoding("UTF-8");   //判断表单是否为上传文件   if (!ServletFileUpload.isMultipartContent(arg0)) {    return;   }  try {   //把每一个input 封装成一个items 形成集合   List<FileItem>items= sf.parseRequest(arg0);   //是否是普通input   for (FileItem fileItem : items) {    if (fileItem.isFormField()) {         String name=fileItem.getFieldName();     String value=fileItem.getString("utf-8");     System.out.println(name+":"+value);    }    else {     //如果上传文件为空     String filename=fileItem.getName();//获取上传文件的文件名     if (filename==null||filename.equals("")) {      //跳过file的input接着遍历其他input

     continue;           }     //文件上传                 InputStream is= fileItem.getInputStream();        FileOutputStream fos=new FileOutputStream(basePath+"/"+filename);    byte[] buffer=new byte[1024];    int len=0;    while((len=is.read(buffer))!=-1){     fos.write(buffer, 0, len);    }    is.close();    fos.close();    fileItem.delete();      mess="成功上传";    }   }  } catch (FileUploadException e) {   // TODO Auto-generated catch block   e.printStackTrace();   mess="上传失败";  }  arg0.setAttribute("mess", mess); }

}

继承HttpServlet类后 实现service方法

其中

DiskFileItemFactory工厂 为了判断传过来的input标签是否为普通标签

if (!ServletFileUpload.isMultipartContent(arg0)) {
   return;
  }

该语句是如果传过来的参数不是文件类型，那么返回不继续执行

上传时是根据定义的文件目录上传