J2EE Servlet上传文件到服务器并相应显示功能的实现代码_Java教程

编辑上传文件的页面upload.html

注意事项：上传方式使用post不能使用get（get不能上传文件）

表单 enctype 属性应该设置为 multipart/form-data.（表示提交的数据是二进制文件）

upload.html

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									<!doctype html>

									<html>

									<head>

									<meta charset="utf-8">

									<title>文件上传</title>

									</head>

									<body>

									  <form action="uploadphotoservlet" method="post" enctype="multipart/form-data">

									    人物名称:<input type="text" name="heroname"/><br>

									    上传头像:<input type="file" name="filepath"/><br>

									    <input type="submit" value="上传">

									  </form>

									</body>

									</html>

uploadptotoservlet文件上传类--上传功能的开发

将commons-io-1.4.jar和commons-fileupload-1.2.2.jar 两个jar包放到web-inf/lib 目录下。

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									import java.io.file;

									import java.io.fileoutputstream;

									import java.io.ioexception;

									import java.io.inputstream;

									import java.io.printwriter;

									import java.util.iterator;

									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;

									/**

									 * servlet implementation class uploadphotoservlet

									 */

									@webservlet("/uploadphotoservlet")

									public class uploadphotoservlet extends httpservlet {

									  private static final long serialversionuid = 1l;

									  /**

									   * @see httpservlet#httpservlet()

									   */

									  public uploadphotoservlet() {

									    super();

									    // todo auto-generated constructor stub

									  }

									  /**

									   * @see httpservlet#doget(httpservletrequest request, httpservletresponse response)

									   */

									  protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {

									    // todo auto-generated method stub

									//    response.getwriter().append("served at: ").append(request.getcontextpath());

									    string filename=null;

									    diskfileitemfactory factory=new diskfileitemfactory();  //磁盘文件条目工厂

									    servletfileupload upload=new servletfileupload(factory); //负责处理上传的文件数据，并将表单中每个输入项封装成一个fileitem对象中

									    //设置上传文件的大小为10m

									    factory.setsizethreshold(2*1024*1024);

									    list items=null;

									    try {

									      //parse 解析

									      items=upload.parserequest(request);  //得到一个保存了所有上传内容的list对象

									    } catch (fileuploadexception e) {

									      // todo auto-generated catch block

									      e.printstacktrace();

									    }

									    iterator iter=items.iterator();  //迭代上传的文件数据

									    while(iter.hasnext()){

									      fileitem item=(fileitem) iter.next();

									      if(!item.isformfield()){ //如果不是上传的

									        //根据时间戳创建头像文件

									        filename=system.currenttimemillis()+".jpg";

									        //通过getrealpath获取上传文件夹，如果项目存在将存在当前项目下 不存在的话创建项目文件夹

									        //图片文件夹

									        string photofolder=request.getservletcontext().getrealpath("uploaded");

									        file f=new file(photofolder,filename);

									        f.getparentfile().mkdirs(); //如果父文件夹不存在则自动创建

									        //通过item.getinputstream() 获取浏览器上传的文件

									        inputstream is = item.getinputstream();  //将文件读进来

									        //复制文件

									        fileoutputstream fos=new fileoutputstream(f); //往界面上显示

									        byte[] b=new byte[2*1024*1024];

									        int len=0;

									        while((len=is.read(b))!=-1){

									          fos.write(b, 0, len);

									        }

									        fos.close();

									      }else{

									        system.out.println(item.getfieldname());//heroname

									        string value=item.getstring();  

									        value=new string(value.getbytes("iso-8859-1"), "utf-8");

									        system.out.println(value);  //桑葚

									      }

									    }

									    string html="<img width='200' height='150' src='uploaded/%s'/>";

									    response.setcontenttype("text/html");

									    printwriter pw=response.getwriter();

									    pw.format(html, filename);

									  }

									  /**

									   * @see httpservlet#dopost(httpservletrequest request, httpservletresponse response)

									   */

									  protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {

									    // todo auto-generated method stub

									    doget(request, response);

									  }

									}