对于打文件上传如果网突然断了，得重新来一遍，是不是很郁闷，怎么办，如果浏览器不支持FileAPI 那就只能使用 Flash来做断点上传，有了HTML5 基于Ajax或者WebSocket 的原生实现也很棒。
下面就是基于websocket + spring 的一个实现例子
好了直接上代码
用户注册
spring 配置
FileUploadSocketHandler
import com.chameleon.document.DocumentBusiness;
import com.chameleon.document.model.File;
import com.chameleon.document.model.FileDiskContent;
import com.chameleon.document.model.FileUploadState;
import com.chameleon.util.Sequence;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.text.DecimalFormat;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.Resource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.socket.BinaryMessage;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.AbstractWebSocketHandler;
/**
*
* @author Johnson.zhang
*/
public class FileUploadSocketHandler extends AbstractWebSocketHandler {
private static final Logger logger = LoggerFactory.getLogger(FileUploadSocketHandler.class);
private Map result = null;
@Resource(name = "documentBusinessImpl")
private DocumentBusiness documentBusiness;
private ObjectMapper objectMapper = new ObjectMapper();
private OutputStream outputStream;
private long fileTotalSize;
private long fileLoadSize;
private DecimalFormat percentFormat = new DecimalFormat("0");
private FileDiskContent fileDiskContent = null;
@Resource(name = "systemFileUploadPath")
private String uploadFilePath;
@Resource(name = "sequenceSerialNumberImpl")
private Sequence sequence;
public void setUploadFilePath(String uploadFilePath) {
this.uploadFilePath = uploadFilePath;
}
public void setObjectMapper(ObjectMapper objectMapper) {
this.objectMapper = objectMapper;
}
public void setSequence(Sequence sequence) {
this.sequence = sequence;
}
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
String id = session.getId();
logger.debug("WebSocket连接已经建立，连接ID为:" + id);
}
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
result = new HashMap();
result.put("buffer", 8192);
fileTotalSize = 0l;
fileLoadSize = 0l;
String msg = message.getPayload();
fileDiskContent = objectMapper.readValue(msg, FileDiskContent.class);
if (fileDiskContent.getId() != null && !fileDiskContent.getId().isEmpty()) {
//续传文件
CloseStatus status = null;
String filePath = fileDiskContent.getPath();
if (filePath == null || filePath.isEmpty()) {
status = new CloseStatus(2001, "续传文件路径不能为空！");
}
java.io.File tempFile = new java.io.File(uploadFilePath + "/" + filePath);
if (!tempFile.exists()) {
status = new CloseStatus(2002, "续传文件不存在！");
}
if (!tempFile.isFile()) {
status = new CloseStatus(2002, "续传文件不能是文件夹！");
}
if (status != null) {
session.close(status);
String rs = objectMapper.writeValueAsString(status);
logger.debug("WebSocket 文件断点续传初始化发生错误: " + rs);
return;
}
outputStream = new FileOutputStream(uploadFilePath + "/" + filePath, true);
fileTotalSize = fileDiskContent.getSize();
fileLoadSize = tempFile.length();
if (fileTotalSize > 0) {
double percent = ((double) fileLoadSize) / fileTotalSize * 100;
result.put("percent", percentFormat.format(percent));
}
result.put("id", fileDiskContent.getId());
result.put("name", fileDiskContent.getName());
result.put("total", fileDiskContent.getSize());
result.put("path", filePath);
result.put("load", fileLoadSize);
logger.debug("WebSocket 文件上传信息为: " + msg);
} else {
//新上传文件
String filePath = sequence.getId();
String tempPath = uploadFilePath + "/" + filePath;
outputStream = new FileOutputStream(tempPath);
fileDiskContent.setPath(filePath);
fileDiskContent.setId(sequence.getId());
fileTotalSize = fileDiskContent.getSize();
result.put("id", fileDiskContent.getId());
result.put("name", fileDiskContent.getName());
result.put("total", fileDiskContent.getSize());
result.put("path", filePath);
result.put("load", fileLoadSize);
result.put("percent", "0");
logger.debug("WebSocket 文件上传信息为: " + msg);
logger.debug("WebSocket 文件保存路径为: " + tempPath);
}
String rs = objectMapper.writeValueAsString(result);
session.sendMessage(new TextMessage(rs));
}
@Override
protected void handleBinaryMessage(WebSocketSession session, BinaryMessage message) throws Exception {
ByteBuffer msg = message.getPayload();
byte[] buffer = msg.array();
outputStream.write(buffer);
fileLoadSize = fileLoadSize + buffer.length;
logger.debug("WebSocket 文件已经上传了 [ " + fileLoadSize + " ] 字节");
result.put("load", fileLoadSize);
if (fileTotalSize > 0) {
double percent = ((double) fileLoadSize) / fileTotalSize * 100;
result.put("percent", percentFormat.format(percent));
}
if (fileLoadSize == fileTotalSize) {
closeStream();
if (fileDiskContent != null) {
if (fileDiskContent.getMeta() == null) {
documentBusiness.saveFile(fileDiskContent);
} else {
documentBusiness.deleteFileUploadStateByFile(fileDiskContent);
}
}
logger.debug("WebSocket 文件已经保存到磁盘：【" + uploadFilePath + "/" + fileDiskContent.getPath() + "】");
logger.debug("WebSocket 文件信息已经保存到数据库 文件ID为：【" + fileDiskContent.getId() + "】");
}
String rs = objectMapper.writeValueAsString(result);
logger.debug("WebSocket 文件上传回显数据位 ：【" + rs + "】");
session.sendMessage(new TextMessage(rs));
}
@Override
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
String rs = objectMapper.writeValueAsString(exception);
if (session.isOpen()) {
session.sendMessage(new TextMessage(rs));
}
logger.debug("WebSocket 程序发生异常 ：【" + rs + "】");
}
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
closeStream();
saveFileUploadState();
String rs = objectMapper.writeValueAsString(status);
logger.debug("WebSocket 连接关闭 ：【" + rs + "】");
}
private void closeStream() throws Exception {
if (outputStream != null) {
outputStream.close();
outputStream = null;
}
}
private void saveFileUploadState() {
if (fileLoadSize < fileTotalSize) {
if (fileDiskContent.getMeta() == null) {
FileUploadState fileUploadState = new FileUploadState();
fileUploadState.setId(sequence.getId());
fileUploadState.setLoadedSize(fileLoadSize);
fileUploadState.setFile(fileDiskContent);
documentBusiness.saveFileUploadState(fileUploadState);
} else {
documentBusiness.updateFileUploadStateByFile(fileDiskContent, fileLoadSize);
}
}
}
}