java使用common-fileupload实现文件上传_JAVA教程

文件上传是网站非常常用的功能，直接使用Servlet获取上传文件还得解析请求参数，比较麻烦，所以一般选择采用apache的开源工具，common-fileupload.这个jar包可以再apache官网上面找到，也可以在struts的lib文件夹下面找到，struts上传的功能就是基于这个实现的。

common-fileupload是依赖于common-io这个包的，所以还需要下载这个包。然后导入到你的项目路径下面。

使用代码如下

				?

									package oop.hg.ytu.servlet; 

									import java.io.File; 

									import java.io.IOException; 

									import java.io.InputStream; 

									import java.util.List; 

									import javax.servlet.ServletException; 

									import javax.servlet.http.HttpServlet; 

									import javax.servlet.http.HttpServletRequest; 

									import javax.servlet.http.HttpServletResponse; 

									import oop.hu.ytu.dao.UploadDomain; 

									import org.apache.commons.fileupload.FileItem; 

									import org.apache.commons.fileupload.disk.DiskFileItemFactory; 

									import org.apache.commons.fileupload.servlet.ServletFileUpload; 

									public class Upload extends HttpServlet { 

									  /** 

									   * 处理用户上传请求 

									   */

									  private static final long serialVersionUID = 1L; 

									  public void doGet(HttpServletRequest request, HttpServletResponse response) 

									      throws ServletException, IOException { 

									  // String describe = request.getParameter("describe"); 

									    DiskFileItemFactory factory = new DiskFileItemFactory(); 

									    @SuppressWarnings("deprecation") 

									    String path = request.getRealPath("/upload");//设置磁盘缓冲路径 

									    factory.setRepository(new File(path)); 

									    factory.setSizeThreshold(1024*1024);//设置创建缓冲大小 

									    ServletFileUpload upload = new ServletFileUpload(factory); 

									    upload.setSizeMax(-1);//设置上传文件限制大小,-1无上限 

									    try { 

									      @SuppressWarnings("unchecked") 

									      List<FileItem> list = upload.parseRequest(request); 

									      String va = null; 

									      for(FileItem item : list){ 

									    //   String name = item.getFieldName(); 

									        if(item.isFormField()){//判断是否是文件流 

									          va = item.getString("UTF-8"); 

									        // System.out.println(name+"="+va); 

									      ///   request.setAttribute(name, value); 

									        }else{ 

									          String value = item.getName();//会将完整路径名传过来 

									          int start = value.lastIndexOf("\\"); 

									          String fileName = value.substring(start+1); 

									      //   request.setAttribute(name, fileName); 

									          InputStream in = item.getInputStream(); 

									          UploadDomain dao = new UploadDomain(); 

									          //item.write(new File(realPath,fileName)); 

									          int index = fileName.lastIndexOf("."); 

									          String realFileName = fileName.substring(0,index); 

									          String type = fileName.substring(index+1); 

									          dao.insert(in, realFileName,type,va);//放入到数据库中 

									        } 

									      } 

									    } catch (Exception e) { 

									      e.printStackTrace(); 

									    } 

									  } 

									  public void doPost(HttpServletRequest request, HttpServletResponse response) 

									      throws ServletException, IOException { 

									    doGet(request, response); 

									  } 

									}

这里分别判断是否是上传的流或者表单里面的参数，比如文本框提交信息，然后将他们插入到数据库中。数据库插入
代码如下

									package oop.hu.ytu.dao; 

									import java.io.InputStream; 

									import java.sql.Connection; 

									import java.sql.PreparedStatement; 

									import java.sql.ResultSet; 

									import oop.hg.ytu.utils.JdbcUtils; 

									/** 

									 * 提供文件上传支持 

									 * @author Administrator 

									 * 

									 */

									public class UploadDomain { 

									  /** 

									   * 将上传的文件流放入到数据库中 

									   */

									  public void insert(InputStream in, String fileName, String type,String describe) throws Exception{//向数据库中写入图片  

									    Connection conn = null;  

									    PreparedStatement ps = null;  

									    ResultSet rs = null;  

									    System.out.println(describe); 

									    try {  

									      // 2.建立连接  

									      conn = JdbcUtils.getConnection(); 

									      // 3.创建语句  

									      String sql = "insert into fileupload(file,filename,type,des) values (?,?,?,?)";  

									      ps = conn.prepareStatement(sql);  

									      ps.setBlob(1, in); 

									      ps.setString(2, fileName); 

									      ps.setString(3, type); 

									      ps.setString(4, describe); 

									      // 4.执行语句  

									      ps.executeUpdate();  

									      in.close();  

									    } finally {  

									      JdbcUtils.free(rs, ps, conn);  

									    }  

									  }  

									}