java应用集锦4:保存大对象 上传显示进度条

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使用fileupload上传文档,并保存到blob字段中,上传的过程中显示进度.

<form name="uploadform" id="uploadform" method="POST"
			action="upload.action" ENCTYPE="multipart/form-data" target="hidden">
			上传文件1：
			<input type="file" id="filename1" name="filename1"
				onchange="setflag(true);"
				onblur="getFileSize('filename1','fileinf1');" name="filename">
			<div id="fileinf1" style="display: none"></div>
			<br>
			上传文件2：
			<input type="file" id="filename2" name="filename2"
				onchange="setflag(true);"
				onblur="getFileSize('filename2','fileinf2');" name="sheet">
			<div id="fileinf2" style="display: none"></div>
			<br>
			上传文件3：
			<input type="file" id="filename3" name="filename3"
				onchange="setflag(true);"
				onblur="getFileSize('filename3','fileinf3');" name="sheet">
			<div id="fileinf3" style="display: none"></div>
			<br>
			上传文件4：
			<input type="file" accept="image/gif" name="filename4" id="filename4"
				onchange="setflag(true);"
				onblur="getFileSize('filename4','fileinf4');" name="sheet">
			<div id="fileinf4" style="display: none"></div>
			<br>
			<button onclick="upload();">
				上传
			</button>
		</form>

 action:

package upload;

import java.io.File;
import java.util.Iterator;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.fileupload.DiskFileUpload;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.ProgressListener;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.lsframe.mvc.ActionContext;

public class NewUpload {
	private Log log = LogFactory.getLog("logger");

	private long maxsize = 1000000000;
	UploadDao dao = new UploadDao();

	public String execute() throws Exception {
		ActionContext context = ActionContext.getContext();
		final HttpServletRequest request = context.getHttpServletRequest();

		DiskFileItemFactory factory = new DiskFileItemFactory();
		// 设置内存里面存储的文件的最大字节
		factory.setSizeThreshold(10000);
		// 设置超出文件大小限制的文件存储的位置！
		factory.setRepository(new File("c:\\temp"));
		ServletFileUpload upload = new ServletFileUpload(factory);
		upload.setSizeMax(maxsize);
		
		// 下面是监听上传的进度的代码.


		ProgressListener progressListener = new ProgressListener() {
			private long megaBytes = -1;
			public void update(long pBytesRead, long pContentLength, int pItems) {
				System.out.println("We are currently reading item " + pItems);
				long mBytes = pBytesRead / 1000000;
				System.out.println(mBytes);
				if (megaBytes == mBytes) {
					return;
				}
				System.out.println(" " + pItems);
				megaBytes = mBytes;
				System.out.println("We are currently reading item " + pItems);
				if (pContentLength == -1) {
					System.out.println("So far, " + pBytesRead
							+ " bytes have been read.");
				} else {
					System.out.println("So far, " + pBytesRead + " of "
							+ pContentLength + " bytes have been read.");
				}
			}
		};
		// 对加载对象添加进度监听.
		upload.setProgressListener(progressListener);
		FileItem fi = null;
		String fileName = "";
		int endtag = 0;
		String shortName = "";
		Iterator it =  null;
		//下面的这句话必须放在上面的进度监听后面才可以在监听里面得到信息!!


		final List fileItems = upload.parseRequest(request);
		try {
			it = fileItems.iterator();
			while (it.hasNext()) {
				fi = (FileItem) it.next();
				fileName = fi.getName();
				endtag = fileName.lastIndexOf("\\");
				if (endtag == -1) {
					continue;
				}
				shortName = fileName.substring(endtag + 1);
				//下面演示保存到数据库的大对象字段
				UploadVO file = new UploadVO(shortName,fi.get(),(int)fi.getSize());
				file = dao.preSaveBlob(file);
				dao.insertIntoBlob(file);				
			}
			request.setAttribute("aaa", "上传OK!");
		} catch (Exception e) {
			e.printStackTrace();
			request.setAttribute("aaa", "上传失败,文件最大不得超过"
					+ new Long(maxsize).toString() + "字节！");
		}
		return "success";
	}

	/**
	 * 得到上传的进度信息,返回进度条的json信息..
	 * 
	 * @return
	 */
	public String getUploadProgress() {
		return null;
	}

	/**
	 * 返回指定文件的大小
	 * 
	 * @param fileName
	 * @return
	 */
	public String getMaxFileSize() {
		String str = new Long(maxsize).toString();
		return str;
	}

}

 

保存到blob字段,首先要插入一个空的blob字段占位,然后再以io流的方式写到数据库中的这个字段:

package upload;

import java.io.IOException;
import java.io.OutputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import oracle.sql.BLOB;

import com.lsframe.jdbc.DBPoolManager;
import com.lsframe.jdbc.DataBase;

public class UploadDao {
	private DataBase dao = new DataBase();

	/**
	 * 添加大对象之前先保存一个位置,添加一个空的对象进去
	 * @return
	 * @throws SQLException 
	 */
	public int insertIntoBlob(UploadVO file) throws SQLException {
		String saveSql = "SELECT BLOB_CONTENT FROM TEST_BLOB_T WHERE BLOB_ID = ? FOR UPDATE";
		Connection conn = null;
		PreparedStatement pstmt = null;
		ResultSet rest = null;
		boolean ans = false;
		conn = DBPoolManager.getInstance().getDBConn();  
		try {
			conn.setAutoCommit(false);
			pstmt = conn.prepareStatement(saveSql);
			pstmt.setString(1, file.getBlobId());
			rest = pstmt.executeQuery();

			if (rest.next()) {
				ans = saveToDatabase((BLOB) rest.getBlob("BLOB_CONTENT"),
						file.getFileContent(), file.getFsize());
			}
			conn.setAutoCommit(true);
		} catch (Exception e) {
			System.out.println("保存大对象到数据库出错!\n错误信息:" + e.getMessage());
		}  finally {
			rest.close();
			pstmt.close();
			conn.close();
        }
		return 0;
	}

	/**
	 * 将大对象以字节流的方式写入到数据库中的blob字段.
	 * @param blobContent 从数据库中返回的blob字段对象
	 * @param fileBody 要添加到字段中的文件,以字节数组的方式保存
	 * @param vSize 文件大小
	 * @return
	 * @throws IOException
	 */
	private boolean saveToDatabase(BLOB blobContent, byte[] fileBody, int vSize)
			throws IOException {
		boolean result = false;
		try {
			OutputStream outstream = blobContent.getBinaryOutputStream();
			outstream.write(fileBody, 0, vSize);
			outstream.close();
			result = true;
		} catch (SQLException e) {
			result = false;
			e.printStackTrace();
		} catch (Exception e) {
			result = false;
			e.printStackTrace();
		}
		return result;
	}

	/**
	 * 预添加大对象到数据库.
	 * @return
	 */
	public UploadVO preSaveBlob(UploadVO file) {
		String getSeq = "SELECT TESTBLOBSEQ.NEXTVAL  FROM DUAL";
		String saveSql = "INSERT INTO TEST_BLOB_T(BLOB_CONTENT,BLOB_TIME,BLOB_SIZE,BLOB_NAME,BLOB_ID) VALUES " +
				"(EMPTY_BLOB(),SYSDATE,?,?,?)";
		List argList = new ArrayList();
		argList.add(file.getFsize());
		argList.add(file.getFileName());
		int ans = 0;
		String seq = "";
		try {
			//查询数据库中的这个文件对应的流水号
			seq = dao.queryForString(getSeq);
			argList.add(seq);
			//保存文件相关信息到数据库,并在文件内容的字段上面插入空的blob对象
			ans = dao.updateRecords(saveSql,argList);
			file.setBlobId(seq);
		} catch (Exception e) {
			System.out.println("预添加大对象失败!\n错误信息:" + e.getMessage());
		}
		return file;
	}
}

 

相关的表的结构:

create table TEST_BLOB_T
(
  BLOB_ID      VARCHAR2(30) not null,
  BLOB_SIZE    NUMBER(20,4),
  BLOB_CONTENT BLOB,
  BLOB_TIME    DATE,
  BLOB_NAME    VARCHAR2(50)
)

 

评论

1 楼 495372396 2012-09-07  

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