mongodb+GridFS文件的上传下载删除
1、背景
最近项目使用mongDB做文件服务器，用于文件存储。所以稍微研究了下mongDB API写了个简单文件上传下载删除示例
2、具体代码
完整demo下载路径：http://download.csdn.net/detail/szs860806/9846782 代码中有完整注释。这里就不一一赘述了。我这里使用的是fileupload做的上传。这里是使用的jar: 
文章图片
代码是用servlet写的，有点长。
package com.yqfz.Servlet;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import javax.servlet.ServletException;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import com.mongodb.DB;
import com.mongodb.MongoClient;
import com.mongodb.ServerAddress;
import com.mongodb.gridfs.GridFS;
import com.mongodb.gridfs.GridFSDBFile;
import com.mongodb.gridfs.GridFSInputFile;
import com.yqfz.pojo.FileInfo;
import com.yqfz.util.BaseResult;
import com.yqfz.util.FileUtils;
import com.yqfz.util.PropertiesUtils;
public class IUploadServlet extends HttpServlet
{
/**
* 注释内容
*/
private static final long serialVersionUID = 1L;
// 上传配置
private static final int MEMORY_THRESHOLD = 1024 * 1024 * 10;
// 3MBprivate static final int MAX_FILE_SIZE = 1024 * 1024 * 40;
// 40MBprivate static final int MAX_REQUEST_SIZE = 1024 * 1024 * 50;
// 50MBprivate static final Long DEFAULT_CHUNK_SIZE = 1024 * 1024 * 10L;
private static final String NOT_RENAME = "1";
// 不重命名private String showPath = PropertiesUtils.loadProperty("conf.properties").get("file_show_url");
// 文件显示路径private MongoClient mongo = null;
private DB db = null;
private GridFS gridFS = null;
private BaseResult baseResult = null;
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException
{
doPost(req, res);
}public void doPost(HttpServletRequest req, HttpServletResponse res)
throws IOException, ServletException
{
String method = req.getParameter("method");
if (method.equals("upload"))
{
upload(req, res);
}
else if (method.equals("delete"))
{
delete(req, res);
}
else if (method.equals("downloadFile"))
{
downloadFile(req, res);
}
}@SuppressWarnings("unchecked")
private void upload(HttpServletRequest req, HttpServletResponse res)
{
baseResult = new BaseResult();
try
{
if (checkForm(req, res))// 检测是否为多媒体上传
return;
String appDir = req.getParameter("appDir");
// 获取上传应用类型
String type = req.getParameter("type");
// 是否需要重命名0或者不传为需要，1为不需要
System.out.println("打印参数：appDir=" + appDir + ",type=" + type);
ServletFileUpload upload = initFileUpload();
// 初始化fileUpload
List fileItems = upload.parseRequest(req);
if (fileItems != null && fileItems.size() > 0)
{
initMongo();
// 初始化mongoDB
String fileShowPath = getFileShowPath(appDir);
// 获取展示地址
List fileList = new ArrayList();
for (FileItem item : fileItems)
{
if (!item.isFormField() && item.getSize() > 0)
{
System.out.println("处理上传的文件 begin");
String oldFileName = item.getName();
String newFileName = getNewFileName(type, oldFileName);
GridFSInputFile file = saveFile(item, newFileName);
// 生成文件信息
FileInfo fileInfo =
new FileInfo(file.getId() + "", newFileName, oldFileName,
FileUtils.formetFileSize(item.getSize()), fileShowPath + "/" + newFileName);
fileList.add(fileInfo);
System.out.println("处理上传的文件 end");
}
}baseResult.setError("上传成功");
baseResult.setErrorCode("0000");
baseResult.setResult(fileList);
}
else
{
baseResult.setError("没有上传文件");
baseResult.setErrorCode("1000");
}if (!NOT_RENAME.equals(type))
{
ajaxOut(baseResult.toString(), res);
}
}
catch (Exception e)
{
System.out.println("使用 fileupload 包时发生异常 ...");
e.printStackTrace();
baseResult.setError("上传失败");
baseResult.setErrorCode("1000");
ajaxOut(baseResult.toString(), res);
}
}private void downloadFile(HttpServletRequest req, HttpServletResponse res)
{
baseResult = new BaseResult();
try
{
String appDir = req.getParameter("appDir");
String filename = req.getParameter("filename");
System.out.println("打印参数：appDir=" + appDir + ",filename=" + filename);
initMongo();
getFileShowPath(appDir);
GridFSDBFile gridFSDBFile = (GridFSDBFile)gridFS.findOne(filename);
if (gridFSDBFile != null)
{OutputStream sos = res.getOutputStream();
res.setCharacterEncoding("UTF-8");
res.setHeader("Access-Control-Allow-Origin", "*");
res.setContentType("application/octet-stream");
res.addHeader("Content-Disposition", "attachment;
filename=\"" + filename + "\"");
gridFSDBFile.writeTo(sos);
sos.flush();
sos.close();
}
}
catch (Exception e)
{
System.out.println("下载文件异常 ...");
e.printStackTrace();
baseResult.setError("下载文件失败");
baseResult.setErrorCode("1000");
ajaxOut(baseResult.toString(), res);
}
}private void delete(HttpServletRequest req, HttpServletResponse res)
{
baseResult = new BaseResult();
try
{
String appDir = req.getParameter("appDir");
String filename = req.getParameter("filename");
System.out.println("打印参数：appDir=" + appDir + ",filename=" + filename);
initMongo();
getFileShowPath(appDir);
gridFS.remove(filename);
baseResult.setError("删除成功");
baseResult.setErrorCode("0000");
ajaxOut(baseResult.toString(), res);
}
catch (Exception e)
{
System.out.println("删除文件异常 ...");
e.printStackTrace();
baseResult.setError("删除文件失败");
baseResult.setErrorCode("1000");
ajaxOut(baseResult.toString(), res);
}
}private boolean checkForm(HttpServletRequest req, HttpServletResponse res)
{
boolean flag = false;
if (!ServletFileUpload.isMultipartContent(req))
{
baseResult.setError("Error: 表单必须包含 enctype=multipart/form-data");
baseResult.setErrorCode("1000");
ajaxOut(baseResult.toString(), res);
flag = true;
}return flag;
}public ServletFileUpload initFileUpload()
{
// 配置上传参数
DiskFileItemFactory diskFactory = new DiskFileItemFactory();
// threshold 极限、临界值，即硬盘缓存 1M
diskFactory.setSizeThreshold(MEMORY_THRESHOLD);
// repository 贮藏室，即临时文件目录
// diskFactory.setRepository(new File(filePath + File.separator + "temp"));
ServletFileUpload upload = new ServletFileUpload(diskFactory);
// 设置最大文件上传值
upload.setFileSizeMax(MAX_FILE_SIZE);
// 设置最大请求值 (包含文件和表单数据)
upload.setSizeMax(MAX_REQUEST_SIZE);
return upload;
}@SuppressWarnings("deprecation")
public void initMongo()
{
//用户名密码校验写法3.0后
//MongoCredentialcredential = MongoCredential.createCredential("root", "qyqapp", "123456".toCharArray());
//mongo = new MongoClient(new ServerAddress("192.168.122.203", 27017),Arrays.asList(credential));
mongo = new MongoClient(new ServerAddress("192.168.122.203", 27017));
db = mongo.getDB("qyqapp");
}public String getFileShowPath(String appDir)
{
String fileShowPath = "";
if (appDir != null && !"".equals(appDir))
{
gridFS = new GridFS(db, appDir);
fileShowPath = showPath + "/" + appDir;
}
else
{
gridFS = new GridFS(db);
fileShowPath = showPath;
}return fileShowPath;
}public String getNewFileName(String type, String oldFileName)
{
String newFileName;
if (NOT_RENAME.equals(type))
{
newFileName = oldFileName;
}
else
{
newFileName =
Long.toString(System.currentTimeMillis()) + oldFileName.substring(oldFileName.lastIndexOf("."));
}return newFileName;
}public GridFSInputFile saveFile(FileItem item, String newFileName)
throws Exception
{
GridFSInputFile file = gridFS.createFile(item.getInputStream());
file.setChunkSize(DEFAULT_CHUNK_SIZE);
file.setFilename(newFileName);
file.setContentType(newFileName.substring(newFileName.lastIndexOf(".")));
file.put("uploadDate", new Date());
file.save();
return file;
}/**
* <一句话功能简述> <功能详细描述> 封装返回json数据
*
* @param strContent [参数说明]
*
* @return void [返回类型说明]
* @exception throws [违例类型] [违例说明]
* @see [类、类#方法、类#成员]
*/
public final void ajaxOut(String strContent, HttpServletResponse res)
{
System.out.println(strContent);
res.setContentType("text/html;
charset=UTF-8");
res.setCharacterEncoding("UTF-8");
res.setHeader("Access-Control-Allow-Origin", "*");
PrintWriter out;
try
{
out = res.getWriter();
out.print(strContent);
out.flush();
out.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
测试页面：
Insert title here
method:
appDir:
type:
filename:
3、注意事项
（1）可以使用
GridFSInputFile file = gridFS.createFile(item.getInputStream());
file.setChunkSize(DEFAULT_CHUNK_SIZE);
设置分片的大小。我这里设置的是小于10M不分片。想看上传的文件是否分片可以使用可视化工具查看
文章图片
默认是256kb
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