J2EE Servlet上传文件到服务器并相应显示功能的实现代码

时间:2022-10-13 15:47:47

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

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
<!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。

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
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);
  }
}

运行结果:

J2EE Servlet上传文件到服务器并相应显示功能的实现代码

总结

以上所述是小编给大家介绍的j2ee servlet上传文件到服务器并相应显示功能的实现代码,希望对大家有所帮助,如果大家有任何疑问请给我留言,小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持!

原文链接:https://www.cnblogs.com/gaohuanhuan/archive/2018/07/06/9271718.html