文件上传

[html]
<%@ taglib prefix="s" uri="/struts-tags"%>
<html>
    <head>
        <title>文件上传</title>
    </head>
    <body>
        <s:form name="idFrmMain" method="post" enctype="multipart/form-data">
            <table style="margin-left: 100px;" border=0 cellspacing=0 cellpadding=2 bordercolor="#FFFFFF" width="400">
                <col span=1 width="3600">
                <tr>
                    <th>上传文件</th>
                    <td>
                        <s:file name="file" size="40" onkeypress="return false;" />
                    </td>
                </tr>
                <tr align="center">
                    <td>
                        <input type="button" style="width: 80px; height: 25" value="上传" onclick="javascript:upload();">
                    </td>
                </tr>
            </table>
        </s:form>
    </body>
</html>

文件为file，文件名必须为file+FileName（即fileFileName）,只有这样才能通过get和set方法自动获取到文件名。该文件名不包括文件的路径
表单中必须加enctype="multipart/form-data"，它用来设置表单的MIME编码。默认情况，编码格式是application/x-www-form-urlencoded，不能用于文件上传；
只有使用了multipart/form-data，才能完整的传递文件数据.enctype="multipart/form-data"是上传二进制数据。
[java]
/** 文件 */
private File file;

/** 文件名 */
private String fileFileName;

public File getFile() {
    return file;
}

public void setFile(File file) {
    this.file = file;
}

public String getFileFileName() {
    return fileFileName;
}

public void setFileFileName(String fileFileName) {
    this.fileFileName = fileFileName;
}

String fileName = this.getFileFileName();
File fileObj = this.getFile();

String uploadPath = ServletActionContext.getServletContext().getRealPath("upload");//上传服务器路径
uploadFile(uploadPath, fileName, FileIO.read(fileObj));//调用uploadFile()方法

[java]
public static void uploadFile(String path, String fileName,
    StringBuffer buffer) throws Exception {

    File file = new File(path);
    if (!file.exists()) {
        file.mkdirs();
    }

    String fullFileName = path + File.separatorChar + fileName;
    BufferedWriter bw = null;
    try {
        bw = getBufferedWriter(fullFileName, false);
        bw.write(buffer.toString());
        bw.flush();
    } catch (FileNotFoundException e) {
        throw new FwApplicationException("文件不存在");
    } finally {
        if (bw != null) {
            bw.close();
        }
    }
}

[java]
public static BufferedWriter getBufferedWriter(String fileName,
    boolean writeMode) throws Exception {

    FileOutputStream fos = null;
    OutputStreamWriter osw = null;
    try {
        fos = new FileOutputStream(fileName, writeMode);
        osw = new OutputStreamWriter(fos, "ISO8859-1");
        return new BufferedWriter(osw);
    } catch (Exception e) {
        try {
            if (osw != null) {
                osw.close();
            } else if (fos != null) {
                fos.close();
            }
        } catch (IOException ioException) {
            LOG.debug("关闭时发生异常", ioException);
        }
        throw e;
    }
}
调用js里的upload()函数
[javascript]
function upload() {
    document.idFrmMain.action = "fileUpload.do";
    document.idFrmMain.target = "_self";
    document.idFrmMain.submit();
}

补充：web前端 , HTML/CSS  ,