java文件上传

技术架构: Struts2 + JSP + jQuery

普通标签上传文件

页面标签

<tr>
    <td class="table_a_td_l">上传附件：</td>
    <td colspan="2" class="table_a_td_r">
        <input name="uploadFile" id="uploadFile" type="file" style="170px;" onchange="return saveData('uploadFile')" >
    </td>
</tr>

前端js

function savaData(labelId) {
    //调用文件上传的JS方法
    var result = ajaxFileUpload(labelId, 30*1024*1024);
    
    if(result == 'false') {//返回false, 上传失败
        return false;
    }else {
        alert(result.fileName);    //原文件名
        alert(result.fileNewName); //新文件名
        alert(result.filePath);    //上传到磁盘路径
        return false;
    }
}

/**
 * 上传文件
 * labelId: 上传控件的Id
 * fileSizeLimit: 上传大小限制(字节)
 */
function ajaxFileUpload(labelId, fileSizeLimit) {
    //获取到文件对象
    var file = $("#"+labelId)[0].files[0];
    result = "false";
    if(null != file) {
        var byteSize = file.size;
        if (byteSize > fileSizeLimit) {
            alert("上传文件大小不能超过"+fileSizeLimit/1024/1024+"MB！");
            return "false";
        }
        var data = new FormData();
        data.append("file", file);
        data.append("filename", file.name);
        $.ajax({
                url : "uploadFile.action",
                type : "POST",
                async : false,
                cache : false,
                processData : false,// 告诉jQuery不要去处理发送的数据
                contentType : false,
                data : data,
                complete:function(XMLHttpRequest,textStatus){  
                    if(textStatus=='timeout'){  
                        var xmlhttp = window.XMLHttpRequest ? new window.XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHttp");  
                        xmlhttp.abort();   
                        alert("网络超时"); 
                        return "false";
                    }  
                }, 
                success : function(data) {
                    if (data.isOk) {
                        //data={"isOk":"true/false", "fileName":"原文件名", "fileNewName":"新文件名", "filePath":"上传到磁盘路径"}
                        result = data;
                    } else {
                        alert(data.info);
                        return "false";
                    }
                },
                error : function(err) {
                    fileUploadFalg = false;
                    alert(err);
                    return "false";
                },
            });
    }
    return result;
}

后台Java代码

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;

//用于返回json（setter/getter）
private Map<String,Object> validateExists = new HashMap<String, Object>(); 
//文件上传（setter/getter）
private File file;
private String fileName;

@Action(value = "uploadFile", interceptorRefs = {
        @InterceptorRef(value = "fileUpload", params={"maximumSize", "314572800"}),
        @InterceptorRef(value = "basicStack")
        },
        results = { 
        @Result(name = "success", type = "json", params= {"root","validateExists"}) })
public String uploadFile(){
    //通过config.properties配置一个文件存放路径, 如D:/upload/jrzx/
    String filePath = FilePathUtil.FILE_ROOT + FilePathUtil.SEPARATOR + Config.getProperty("file.jrzx.logo") + FilePathUtil.SEPARATOR;
    try {
        String storageFileName = generateFileName(fileName);
        if (null != file) {
            if (314572800 < file.length()) { //大小不能超过300M
                validateExists.put("isOk", false);
                validateExists.put("info", "文件大小不能超过300M");
            } else {
                File path = new File(filePath + storageFileName);
                if (path.exists()) {
                    FileUtils.deleteQuietly(path);
                }
                FileUtils.moveFile(file, path);
                validateExists.put("fileName", fileName);
                validateExists.put("fileNewName", storageFileName);
                validateExists.put("filePath",FilePathUtil.getVirtualPathBya( filePath + storageFileName));
                validateExists.put("isOk", true);
                validateExists.put("info", "上传成功");
            }
        } else {
            validateExists.put("isOk", false);
            validateExists.put("info", "请选择正确的文件格式和文件大小");
        }
    } catch (Exception e) {
        e.printStackTrace();
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        e.printStackTrace(pw);
        log.error(sw.toString());
        validateExists.put("isOk", false);
        validateExists.put("info", "系统异常，请稍候重试！");
    }
    return SUCCESS;
}

private String generateFileName(String fileName) {
    String newFileName = new SimpleDateFormat("yyyyMMddHHmmssSSS").format(new Date()) + (int)(Math.random()*9000+1000);
    String prefix = FilenameUtils.getExtension(fileName);
    if (!Tool.isEmpty(prefix)) {
        newFileName += "." + prefix;
    }
    return newFileName;
}

将上传控件修改为按钮（可以方便的修改样式）

下面这种方式应该也适合用"点击图片上传文件", 暂未尝试, 应该没问题

页面标签

<td class="table_a_td_l">上传附件：</td>

<!-- <td colspan="2" class="table_a_td_r">
    <input name="uploadFile" id="uploadFile" type="file"> onchange="return savaData('attributeId', 'uploadFile', 999*1024*1024)" 
</td> -->

<s:hidden name="news.filePath" ></s:hidden>
<s:hidden name="news.fileOldPath" ></s:hidden>
<s:hidden name="news.fileName" ></s:hidden>
<s:hidden name="news.fileOldName" ></s:hidden>
<td colspan="1" class="table_a_td_r">
    <label for="fileinp">
            <input type="button" value="选择文件">
                <s:if test="news.fileName != null"><span id="uploadFileBtnText">${news.fileName}</span></s:if>
                <s:else><span id="uploadFileBtnText">未选择任何文件</span></s:else>
            <input name="uploadFile" id="uploadFile" type="file"  onchange="return fileChange('未选择任何文件')">
            
    </label>&nbsp;
    <label>
        <input type="button" value="删除" onclick="deleteUploadFile('未选择任何文件')">
        <!-- <img src="${basePath}/images/sc.gif" alt="删除"width="37" height="19" border="0"  /> -->
    </label>
</td>
<style>
    label{
        position: relative;
    } 
    #uploadFile{
        position: absolute;
        left: 0;
        top: 0;
        opacity: 0;
    }
</style>

前端js

//当附件信息变更时的操作
function fileChange(defaultMsg) {
    var uploadFilename = $("#uploadFile").val();
    if(isEmpty(uploadFilename)) {
        $("#uploadFileBtnText").html(defaultMsg);
        $("#newsForm_news_fileName").val("")
    }else {
        var arr = uploadFilename.split("\");
        $("#uploadFileBtnText").html(arr[arr.length-1]);
        $("#newsForm_news_fileName").val(arr[arr.length-1])
    }
    
}

function deleteUploadFile(defaultMsg) {
    if(isEmpty($("#newsForm_news_fileName").val())){
        alert("不存在需要删除的附件！");
        return false;
    }
    
    if(confirm("你确定删除附件吗？

删除附件需要提交后才能生效！")){
        $("#uploadFileBtnText").html(defaultMsg);
        $("#newsForm_news_fileName").val("")
        return false;
    }
    
}

function saveNews(){
    if(confirm("你确定提交吗？") && checkForm()){
        var hasFile = $("#uploadFileBtnText").html();
        var filePath = $("#newsForm_news_filePath").val();
        var fileName = $("#newsForm_news_fileName").val();
        var fileOldName = $("#newsForm_news_fileOldName").val();
        
        //只要存在数据, 那就上传数据(因为即使文件名相同, 内容可能变更了), 然后后台再删除旧的数据
        var result = "false";    var labelId = "uploadFile";   var fileSizeLimit = 999*1024*1024;
        if( !isEmpty(fileName) && !isEmpty($("#"+labelId)[0].files[0])) {
            result = ajaxFileUpload(labelId, fileSizeLimit); //上传文件
        }else { //不存在数据, 不需要上传
            result = {"filePath":"", "fileName":""}; 
        }
        
        //alert($("#uploadFileBtnText").html());
        if(result != 'false') {//如果返回false
            //alert("上传文件成功");
            //alert(result.fileName);    //原文件名
            //alert(result.fileNewName); //新文件名
            //alert(result.filePath);    //上传到磁盘路径
            //将当前的附件信息设置到隐藏域
            $("#newsForm_news_filePath").val(result.filePath);
            $("#newsForm_news_fileName").val(result.fileName);
            //提交表单,保存数据
            var rebutUrl = "saveNewsOfCs.action";
            //$("#domains").val(getSelectTree("showDomains"))
            $("#newsForm").attr("action", rebutUrl).submit();
            return true;
        }else {
　　　　　　　 return false;
　　　　　}
    }else{
       return false;
    }
}