常见的几种jsp和struts中文件下传方法总结

使用FileUpload组件上传文件

文件上传在web应用中非常普遍，要在jsp环境中实现文件上传功能是非常容易的，因为网上有许多用java开发的文件上传组件，本文以commons-fileupload组件为例，为jsp应用添加文件上传功能。
common-fileupload组件是apache的一个开源项目之一，可以从http://jakarta.apache.org/commons/fileupload/下载。用该组件可实现一次上传一个或多个文件，并可限制文件大小。
下载后解压zip包，将commons-fileupload-1.0.jar复制到tomcat的webapps\你的webapp\WEB-INF\lib\下，目录不存在请自建目录。
新建一个servlet: Upload.java用于文件上传：

Java代码

1. public?class?Upload?extends?HttpServlet?{ ??
2. ??
3. ????private?String?uploadPath?=?"C:\\upload\\";?//?上传文件的目录 ??
4. ????private?String?tempPath?=?"C:\\upload\\tmp\\";?//?临时文件目录 ??
5. ??
6. ????public?void?doPost(HttpServletRequest?request, ??
7. ????HttpServletResponse?response) ??
8. ????throws?IOException,?ServletException ??
9. ????{ ??
10. ????} ??
11. } ??
12. 在doPost()方法中，当servlet收到浏览器发出的Post请求后，实现文件上传。以下是示例代码： ??
13. public?void?doPost(HttpServletRequest?request, ??
14. HttpServletResponse?response) ??
15. throws?IOException,?ServletException ??
16. { ??
17. ????try?{ ??
18. ????????DiskFileUpload?fu?=?new?DiskFileUpload(); ??
19. ????????//?设置最大文件尺寸，这里是4MB ??
20. ????????fu.setSizeMax(4194304); ??
21. ????????//?设置缓冲区大小，这里是4kb ??
22. ????????fu.setSizeThreshold(4096); ??
23. ????????//?设置临时目录： ??
24. ????????fu.setRepositoryPath(tempPath); ??
25. ??
26. ????????//?得到所有的文件： ??
27. ????????List?fileItems?=?fu.parseRequest(request); ??
28. ????????Iterator?i?=?fileItems.iterator(); ??
29. ????????//?依次处理每一个文件： ??
30. ????????while(i.hasNext())?{ ??
31. ????????????FileItem?fi?=?(FileItem)i.next(); ??
32. ????????????//?获得文件名，这个文件名包括路径： ??
33. ????????????String?fileName?=?fi.getName(); ??
34. ????????????//?在这里可以记录用户和文件信息 ??
35. ????????????//?... ??
36. ????????????//?写入文件，暂定文件名为a.txt，可以从fileName中提取文件名： ??
37. ????????????fi.write(new?File(uploadPath?+?"a.txt")); ??
38. ????????} ??
39. ????} ??
40. ????catch(Exception?e)?{ ??
41. ????????//?可以跳转出错页面 ??
42. ????} ??
43. } ??
44. 如果要在配置文件中读取指定的上传文件夹，可以在init()方法中执行： ??
45. public?void?init()?throws?ServletException?{ ??
46. ????uploadPath?=?.... ??
47. ????tempPath?=?.... ??
48. ????//?文件夹不存在就自动创建： ??
49. ????if(!new?File(uploadPath).isDirectory()) ??
50. ????????new?File(uploadPath).mkdirs(); ??
51. ????if(!new?File(tempPath).isDirectory()) ??
52. ????????new?File(tempPath).mkdirs(); ??
53. }??

public class Upload extends HttpServlet {

    private String uploadPath = "C:\\upload\\"; // 上传文件的目录
    private String tempPath = "C:\\upload\\tmp\\"; // 临时文件目录

    public void doPost(HttpServletRequest request,
    HttpServletResponse response)
    throws IOException, ServletException
    {
    }
}
在doPost()方法中，当servlet收到浏览器发出的Post请求后，实现文件上传。以下是示例代码：
public void doPost(HttpServletRequest request,
HttpServletResponse response)
throws IOException, ServletException
{
    try {
        DiskFileUpload fu = new DiskFileUpload();
        // 设置最大文件尺寸，这里是4MB
        fu.setSizeMax(4194304);
        // 设置缓冲区大小，这里是4kb
        fu.setSizeThreshold(4096);
        // 设置临时目录：
        fu.setRepositoryPath(tempPath);

        // 得到所有的文件：
        List fileItems = fu.parseRequest(request);
        Iterator i = fileItems.iterator();
        // 依次处理每一个文件：
        while(i.hasNext()) {
            FileItem fi = (FileItem)i.next();
            // 获得文件名，这个文件名包括路径：
            String fileName = fi.getName();
            // 在这里可以记录用户和文件信息
            // ...
            // 写入文件，暂定文件名为a.txt，可以从fileName中提取文件名：
            fi.write(new File(uploadPath + "a.txt"));
        }
    }
    catch(Exception e) {
        // 可以跳转出错页面
    }
}
如果要在配置文件中读取指定的上传文件夹，可以在init()方法中执行：
public void init() throws ServletException {
    uploadPath = ....
    tempPath = ....
    // 文件夹不存在就自动创建：
    if(!new File(uploadPath).isDirectory())
        new File(uploadPath).mkdirs();
    if(!new File(tempPath).isDirectory())
        new File(tempPath).mkdirs();
}

编译该servlet，注意要指定classpath，确保包含commons-upload-1.0.jar和tomcat\common\lib\servlet-api.jar。
配置servlet，用记事本打开tomcat\webapps\你的webapp\WEB-INF\web.xml，没有的话新建一个。
典型配置如下：

Web.xml代码

1. <?xml?version="1.0"?encoding="ISO-8859-1"?> ??
2. <!DOCTYPE?web-app ??
3. ????PUBLIC?"-//Sun?Microsystems,?Inc.//DTD?Web?Application?2.3//EN"??
4. ????"http://java.sun.com/dtd/web-app_2_3.dtd"> ??
5. ??
6. <web-app> ??
7. ????<servlet> ??
8. ????????<servlet-name>Upload</servlet-name> ??
9. ????????<servlet-class>Upload</servlet-class> ??
10. ????</servlet> ??
11. ??
12. ????<servlet-mapping> ??
13. ????????<servlet-name>Upload</servlet-name> ??
14. ????????<url-pattern>/fileupload</url-pattern> ??
15. ????</servlet-mapping> ??
16. </web-app>??

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
    <servlet>
        <servlet-name>Upload</servlet-name>
        <servlet-class>Upload</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Upload</servlet-name>
        <url-pattern>/fileupload</url-pattern>
    </servlet-mapping>
</web-app>

配置好servlet后，启动tomcat，写一个简单的html测试：

Struts代码

1. <form?action="fileupload"?method="post"??
2. enctype="multipart/form-data"?name="form1"> ??
3. ??<input?type="file"?name="file"> ??
4. ??<input?type="submit"?name="Submit"?value="upload"> ??
5. </form>??

<form action="fileupload" method="post"
enctype="multipart/form-data" name="form1">
  <input type="file" name="file">
  <input type="submit" name="Submit" value="upload">
</form>

注意action="fileupload"其中fileupload是配置servlet时指定的url-pattern。

二：
选择上传文件页面：selfile.jsp，如此访问此页面：

Jsp代码

1. <html:link?module="/upload"?page="/upload.do">?继续上传</html:link></h2>? ??
2. ??
3. --------------------------------------------? ??
4. <%@?page?contentType="text/html;?charset=GBK"?%>? ??
5. <%@?page?import="org.apache.struts.action.*,? ??
6. ?????????????????java.util.Iterator,? ??
7. ?????????????????org.apache.struts.Globals"?%>? ??
8. <%@?taglib?uri="/tags/struts-bean"?prefix="bean"?%>? ??
9. <%@?taglib?uri="/tags/struts-html"?prefix="html"?%>? ??
10. <%@?taglib?uri="/tags/struts-logic"?prefix="logic"?%>? ??
11. <logic:messagesPresent>? ??
12. ???<ul>? ??
13. ???<html:messages?id="error">? ??
14. ??????<li><bean:write?name="error"/></li>? ??
15. ???</html:messages>? ??
16. ???</ul><hr?/>? ??
17. </logic:messagesPresent>? ??
18. <html:html>? ??
19. ??
20. <html:form?action="uploadsAction.do"?enctype="multipart/form-data">? ??
21. <html:file?property="theFile"/>? ??
22. <html:submit/>? ??
23. </html:form>? ??
24. </html:html>???

<html:link module="/upload" page="/upload.do"> 继续上传</html:link></h2> 

-------------------------------------------- 
<%@ page contentType="text/html; charset=GBK" %> 
<%@ page import="org.apache.struts.action.*, 
                 java.util.Iterator, 
                 org.apache.struts.Globals" %> 
<%@ taglib uri="/tags/struts-bean" prefix="bean" %> 
<%@ taglib uri="/tags/struts-html" prefix="html" %> 
<%@ taglib uri="/tags/struts-logic" prefix="logic" %> 
<logic:messagesPresent> 
   <ul> 
   <html:messages id="error"> 
      <li><bean:write name="error"/></li> 
   </html:messages> 
   </ul><hr /> 
</logic:messagesPresent> 
<html:html> 

<html:form action="uploadsAction.do" enctype="multipart/form-data"> 
<html:file property="theFile"/> 
<html:submit/> 
</html:form> 
</html:html> 

表单bean:? UpLoadForm.java

Java代码

1. package?org.apache.struts.webapp.upload;? ??
2. import?javax.servlet.http.HttpServletRequest;? ??
3. import?org.apache.struts.action.*;? ??
4. import?org.apache.struts.upload.*;? ??
5. ??
6. /**? ?
7. ?*?<p>Title:UpLoadForm</p>? ?
8. ?*?<p>Description:?QRRSMMS?</p>? ?
9. ?*?<p>Copyright:?Copyright?(c)?2004?jiahansoft</p>? ?
10. ?*?<p>Company:?jiahansoft</p>? ?
11. ?*?@author?wanghw? ?
12. ?*?@version?1.0? ?
13. ?*/? ??
14. ??
15. public?class?UpLoadForm?extends?ActionForm?{? ??
16. ??public?static?final?String?ERROR_PROPERTY_MAX_LENGTH_EXCEEDED?=?"org.apache.struts.webapp.upload.MaxLengthExceeded";? ??
17. ??protected?FormFile?theFile;? ??
18. ??public?FormFile?getTheFile()?{? ??
19. ??????return?theFile;? ??
20. ??}? ??
21. ??public?void?setTheFile(FormFile?theFile)?{? ??
22. ??????this.theFile?=?theFile;? ??
23. ??}? ??
24. ???public?ActionErrors?validate(? ??
25. ????????ActionMapping?mapping,? ??
26. ????????HttpServletRequest?request)?{? ??
27. ????????????? ??
28. ????????ActionErrors?errors?=?null;? ??
29. ????????//has?the?maximum?length?been?exceeded?? ??
30. ????????Boolean?maxLengthExceeded?=? ??
31. ????????????(Boolean)?request.getAttribute(? ??
32. ????????????????MultipartRequestHandler.ATTRIBUTE_MAX_LENGTH_EXCEEDED);? ??
33. ????????????????? ??
34. ????????if?((maxLengthExceeded?!=?null)?&&?(maxLengthExceeded.booleanValue()))?{? ??
35. ????????????errors?=?new?ActionErrors();? ??
36. ????????????errors.add(? ??
37. ????????????????ActionMessages.GLOBAL_MESSAGE?,? ??
38. ????????????????new?ActionMessage("maxLengthExceeded"));? ??
39. ????????????errors.add(? ??
40. ????????????????ActionMessages.GLOBAL_MESSAGE?,? ??
41. ????????????????new?ActionMessage("maxLengthExplanation"));? ??
42. ????????}? ??
43. ????????return?errors;? ??
44. ??
45. ????}? ??
46. ??
47. }???

package org.apache.struts.webapp.upload; 
import javax.servlet.http.HttpServletRequest; 
import org.apache.struts.action.*; 
import org.apache.struts.upload.*; 

/** 
 * <p>Title:UpLoadForm</p> 
 * <p>Description: QRRSMMS </p> 
 * <p>Copyright: Copyright (c) 2004 jiahansoft</p> 
 * <p>Company: jiahansoft</p> 
 * @author wanghw 
 * @version 1.0 
 */ 

public class UpLoadForm extends ActionForm { 
  public static final String ERROR_PROPERTY_MAX_LENGTH_EXCEEDED = "org.apache.struts.webapp.upload.MaxLengthExceeded"; 
  protected FormFile theFile; 
  public FormFile getTheFile() { 
      return theFile; 
  } 
  public void setTheFile(FormFile theFile) { 
      this.theFile = theFile; 
  } 
   public ActionErrors validate( 
        ActionMapping mapping, 
        HttpServletRequest request) { 
             
        ActionErrors errors = null; 
        //has the maximum length been exceeded? 
        Boolean maxLengthExceeded = 
            (Boolean) request.getAttribute( 
                MultipartRequestHandler.ATTRIBUTE_MAX_LENGTH_EXCEEDED); 
                 
        if ((maxLengthExceeded != null) && (maxLengthExceeded.booleanValue())) { 
            errors = new ActionErrors(); 
            errors.add( 
                ActionMessages.GLOBAL_MESSAGE , 
                new ActionMessage("maxLengthExceeded")); 
            errors.add( 
                ActionMessages.GLOBAL_MESSAGE , 
                new ActionMessage("maxLengthExplanation")); 
        } 
        return errors; 

    } 

} 

处理上传的文件：UpLoadAction.java?

Java代码

1. package?org.apache.struts.webapp.upload;? ??
2. import?java.io.*;? ??
3. import?javax.servlet.http.*;? ??
4. import?org.apache.struts.action.*;? ??
5. import?org.apache.struts.upload.FormFile;?? ??
6. ??
7. /**? ?
8. ?*?<p>Title:UpLoadAction</p>? ?
9. ?*?<p>Description:?QRRSMMS?</p>? ?
10. ?*?<p>Copyright:?Copyright?(c)?2004?jiahansoft</p>? ?
11. ?*?<p>Company:?jiahansoft</p>? ?
12. ?*?@author?wanghw? ?
13. ?*?@version?1.0? ?
14. ?*/? ??
15. ??
16. public?class?UpLoadAction?extends?Action?{? ??
17. ??public?ActionForward?execute(ActionMapping?mapping,? ??
18. ???????????????????????????????ActionForm?form,? ??
19. ???????????????????????????????HttpServletRequest?request,? ??
20. ???????????????????????????????HttpServletResponse?response)? ??
21. ??????throws?Exception?{? ??
22. ???????if?(form?instanceof?UpLoadForm)?{//如果form是UpLoadsForm? ??
23. ???????????String?encoding?=?request.getCharacterEncoding();? ??
24. ??
25. ???????if?((encoding?!=?null)?&&?(encoding.equalsIgnoreCase("utf-8")))? ??
26. ????????{? ??
27. ????????????response.setContentType("text/html;?charset=gb2312");? ??
28. ????????}? ??
29. ????????UpLoadForm?theForm?=?(UpLoadForm?)?form;? ??
30. ????????FormFile?file?=?theForm.getTheFile();//取得上传的文件? ??
31. ????????String?contentType?=?file.getContentType();? ??
32. ??
33. ????????String?size?=?(file.getFileSize()?+?"?bytes");//文件大小? ??
34. ????????String?fileName=?file.getFileName();//文件名? ??
35. ????????try?{? ??
36. ??????????InputStream?stream?=?file.getInputStream();//把文件读入? ??
37. ??????????String?filePath?=?request.getRealPath("/");//取当前系统路径? ??
38. ??????????ByteArrayOutputStream?baos?=?new?ByteArrayOutputStream();? ??
39. ??????????OutputStream?bos?=?new?FileOutputStream(filePath?+?"/"?+? ??
40. ??????????????????????????????????????????????????file.getFileName());? ??
41. ??????????????//建立一个上传文件的输出流，将上传文件存入web应用的根目录。? ??
42. ??????????//System.out.println(filePath+"/"+file.getFileName());? ??
43. ??????????int?bytesRead?=?0;? ??
44. ??????????byte[]?buffer?=?new?byte[8192];? ??
45. ??????????while?(?(bytesRead?=?stream.read(buffer,?0,?8192))?!=?-1)?{? ??
46. ????????????bos.write(buffer,?0,?bytesRead);//将文件写入服务器? ??
47. ??????????}? ??
48. ??????????bos.close();? ??
49. ??????????stream.close();? ??
50. ????????}catch(Exception?e){? ??
51. ??????????System.err.print(e);? ??
52. ????????}? ??
53. ????????//request.setAttribute("dat",file.getFileName());? ??
54. ?????????request.setAttribute("contentType",?contentType);? ??
55. ?????????request.setAttribute("size",?size);? ??
56. ?????????request.setAttribute("fileName",?fileName);? ??
57. ??
58. ????????return?mapping.findForward("display");? ??
59. ????}? ??
60. ????return?null;? ??
61. ??}? ??
62. }???

package org.apache.struts.webapp.upload; 
import java.io.*; 
import javax.servlet.http.*; 
import org.apache.struts.action.*; 
import org.apache.struts.upload.FormFile;  

/** 
 * <p>Title:UpLoadAction</p> 
 * <p>Description: QRRSMMS </p> 
 * <p>Copyright: Copyright (c) 2004 jiahansoft</p> 
 * <p>Company: jiahansoft</p> 
 * @author wanghw 
 * @version 1.0 
 */ 

public class UpLoadAction extends Action { 
  public ActionForward execute(ActionMapping mapping, 
                               ActionForm form, 
                               HttpServletRequest request, 
                               HttpServletResponse response) 
      throws Exception { 
       if (form instanceof UpLoadForm) {//如果form是UpLoadsForm 
           String encoding = request.getCharacterEncoding(); 

       if ((encoding != null) && (encoding.equalsIgnoreCase("utf-8"))) 
        { 
            response.setContentType("text/html; charset=gb2312"); 
        } 
        UpLoadForm theForm = (UpLoadForm ) form; 
        FormFile file = theForm.getTheFile();//取得上传的文件 
        String contentType = file.getContentType(); 

        String size = (file.getFileSize() + " bytes");//文件大小 
        String fileName= file.getFileName();//文件名 
        try { 
          InputStream stream = file.getInputStream();//把文件读入 
          String filePath = request.getRealPath("/");//取当前系统路径 
          ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
          OutputStream bos = new FileOutputStream(filePath + "/" + 
                                                  file.getFileName()); 
              //建立一个上传文件的输出流，将上传文件存入web应用的根目录。 
          //System.out.println(filePath+"/"+file.getFileName()); 
          int bytesRead = 0; 
          byte[] buffer = new byte[8192]; 
          while ( (bytesRead = stream.read(buffer, 0, 8192)) != -1) { 
            bos.write(buffer, 0, bytesRead);//将文件写入服务器 
          } 
          bos.close(); 
          stream.close(); 
        }catch(Exception e){ 
          System.err.print(e); 
        } 
        //request.setAttribute("dat",file.getFileName()); 
         request.setAttribute("contentType", contentType); 
         request.setAttribute("size", size); 
         request.setAttribute("fileName", fileName); 

        return mapping.findForward("display"); 
    } 
    return null; 
  } 
} 

成功页display.jsp?

Jsp代码

1. <%@?page?contentType="text/html;?charset=GBK"?%>? ??
2. <%@?page?import="org.apache.struts.action.*,? ??
3. ?????????????????java.util.Iterator,? ??
4. ?????????????????org.apache.struts.Globals"?%>? ??
5. <%@?taglib?uri="/tags/struts-html"?prefix="html"?%>? ??
6. ??
7. ??
8. 上传成功！上传信息如下：? ??
9. <p>? ??
10. <b>The?File?name:</b>?<%=?request.getAttribute("fileName")?%>? ??
11. </p>? ??
12. <p>? ??
13. <b>The?File?content?type:</b>?<%=?request.getAttribute("contentType")?%>? ??
14. </p>? ??
15. <p>? ??
16. <b>The?File?size:</b>?<%=?request.getAttribute("size")?%>? ??
17. </p>? ??
18. <hr?/>? ??
19. <hr?/>? ??
20. <html:link?module="/upload"?page="/upload.do">?继续上传</html:link></h2>???

<%@ page contentType="text/html; charset=GBK" %> 
<%@ page import="org.apache.struts.action.*, 
                 java.util.Iterator, 
                 org.apache.struts.Globals" %> 
<%@ taglib uri="/tags/struts-html" prefix="html" %> 


上传成功！上传信息如下： 
<p> 
<b>The File name:</b> <%= request.getAttribute("fileName") %> 
</p> 
<p> 
<b>The File content type:</b> <%= request.getAttribute("contentType") %> 
</p> 
<p> 
<b>The File size:</b> <%= request.getAttribute("size") %> 
</p> 
<hr /> 
<hr /> 
<html:link module="/upload" page="/upload.do"> 继续上传</html:link></h2> 

六、测试
从本站下载整个目录结构TestStruts并放入tomcat的webapps目录下，在浏览器中输入：
http://127.0.0.1:8080/TestStruts/upload/upload.do

原文：http://jc-dreaming.iteye.com/blog/637923