最近,项目中遇到一个问题:通过Socket方式上传头像到服务器后,读取服务器的返回数据时要等待很久,导致用户体验非常差。但是这个问题在ios手机端却不存在,因为ios采取的http文件上传方式。一开始我纠结于为何服务器迟迟没有返回文件的位置,手机客户端已经将文件上传完了呀?
我的代码是这样滴(请关注文件上传完成后处理):
public static String post(String path, Map<String, String> params, FormFile[] files) throws Exception {
final String BOUNDARY = "---------------------------7da2137580612"; // 数据分隔线
final String endline = "--" + BOUNDARY + "--\r\n";// 数据结束标志
final int BUFFER_SIZE = 1024 * 1024;
int fileDataLength = 0;
for (FormFile uploadFile : files) {// 得到文件类型数据的总长度
StringBuilder fileExplain = new StringBuilder();
fileExplain.append("--");
fileExplain.append(BOUNDARY);
fileExplain.append("\r\n");
fileExplain.append("Content-Disposition: form-data;name=\"" + uploadFile.getParameterName()
+ "\";filename=\"" + uploadFile.getFilname() + "\"\r\n");
fileExplain.append("Content-Type: " + uploadFile.getContentType() + "\r\n\r\n");
fileExplain.append("\r\n");
fileDataLength += fileExplain.length();
if (uploadFile.getInStream() != null) {
fileDataLength += uploadFile.getFile().length();
} else {
fileDataLength += uploadFile.getData().length;
}
}
StringBuilder textEntity = new StringBuilder();
for (Map.Entry<String, String> entry : params.entrySet()) {// 构造文本类型参数的实体数据
textEntity.append("--");
textEntity.append(BOUNDARY);
textEntity.append("\r\n");
textEntity.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"\r\n\r\n");
textEntity.append(entry.getValue());
textEntity.append("\r\n");
}
// 计算传输给服务器的实体数据总长度
int dataLength = textEntity.toString().getBytes().length + fileDataLength + endline.getBytes().length;
URL url = new URL(path);
int port = url.getPort() == -1 ? 80 : url.getPort();
Socket socket = new Socket(InetAddress.getByName(url.getHost()), port);
OutputStream outStream = socket.getOutputStream();
// 下面完成HTTP请求头的发送
String requestmethod = "POST " + url.getPath() + " HTTP/1.1\r\n";
outStream.write(requestmethod.getBytes());
String accept = "Accept: image/gif, image/jpeg, image/pjpeg, text/plain, application/x-shockwave-flash, application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*\r\n";
outStream.write(accept.getBytes());
String language = "Accept-Language: zh-CN\r\n";
outStream.write(language.getBytes());
String contenttype = "Content-Type: multipart/form-data; boundary=" + BOUNDARY + "\r\n";
outStream.write(contenttype.getBytes());
String contentlength = "Content-Length: " + dataLength + "\r\n";
outStream.write(contentlength.getBytes());
String alive = "Connection: Keep-Alive\r\n";
outStream.write(alive.getBytes());
String host = "Host: " + url.getHost() + ":" + port + "\r\n";
outStream.write(host.getBytes());
// 写完HTTP请求头后根据HTTP协议再写一个回车换行
outStream.write("\r\n".getBytes());
// 把所有文本类型的实体数据发送出来
outStream.write(textEntity.toString().getBytes());
// 把所有文件类型的实体数据发送出来
for (FormFile uploadFile : files) {
StringBuilder fileEntity = new StringBuilder();
fileEntity.append("--");
fileEntity.append(BOUNDARY);
fileEntity.append("\r\n");
fileEntity.append("Content-Disposition: form-data;name=\"" + uploadFile.getParameterName()
+ "\";filename=\"" + uploadFile.getFilname() + "\"\r\n");
fileEntity.append("Content-Type: " + uploadFile.getContentType() + "\r\n\r\n");
outStream.write(fileEntity.toString().getBytes());
if (uploadFile.getInStream() != null) {
byte[] buffer = new byte[1024];
int len = 0;
while ((len = uploadFile.getInStream().read(buffer, 0, 1024)) != -1) {
outStream.write(buffer, 0, len);
}
uploadFile.getInStream().close();
} else {
outStream.write(uploadFile.getData(), 0, uploadFile.getData().length);
}
outStream.write("\r\n".getBytes());
}
// 下面发送数据结束标志,表示数据已经结束
outStream.write(endline.getBytes());
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
if (reader.readLine().indexOf("200") == -1) {// 读取web服务器返回的数据,判断请求码是否为200,如果不是200,代表请求失败
return null;
}
char[] data = new char[BUFFER_SIZE];
int len = -1;
String responseMsg = null;
while((len = reader.read(data)) != -1)
{
responseMsg += String.valueOf(data, 0, len);
}
outStream.flush();
outStream.close();
reader.close();
socket.close();
LogUtil.d("SocketHttpUpload/ post() response: " + responseMsg);
return responseMsg;
}
通过debug跟踪发现,第一次执行
while((len = reader.read(data)) != -1)
{
responseMsg += String.valueOf(data, 0, len);
}
responseMsg就已经得到了文件的地址,但是第二次执行reader.read(data) 时却卡住了,过了很长时间才读到数据-1,为何呢?感觉就是服务器向客户端写数据结束了,却没告诉客户端已经写结束了,所以就开始怀疑服务器代码有问题,可是为何ios却没这个问题呢?无奈之下,只能继续从自身找原因了。幸好看到了这个博客
android通过socket发送大文件到服务器并返回结果,找到了问题的原因才得以解决。
原来socket.getOutputStream()传送完文件后,需要关闭socket的OutputStream(socket.shutdownOutput();),如果不关闭客户端的输出流,那么服务器端socket获取输入流对象后,调用这个对象的read方法会在执行完后一直处于等待状态,也就是read阻塞。
修改后代码如下:
//省略部分代码
...........
// 下面发送数据结束标志,表示数据已经结束
outStream.write(endline.getBytes());
outStream.flush();
// 一定要加上这句,否则收不到来自服务器端的消息返回
socket.shutdownOutput();
BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
if (reader.readLine().indexOf("200") == -1) {// 读取web服务器返回的数据,判断请求码是否为200,如果不是200,代表请求失败
return null;
}
char[] data = new char[BUFFER_SIZE];
int len = -1;
String responseMsg = null;
while((len = reader.read(data)) != -1)
{
responseMsg += String.valueOf(data, 0, len);
}
//省略部分代码
...........