Java 通过post将文件上载到服务器OutOfMemory
我正在开发一个远程备份应用程序,有时我需要上传大文件,例如15MB,我在一些手机上测试过,我发现内存不足错误 使用此功能是否有减少内存使用的方法Java 通过post将文件上载到服务器OutOfMemory,java,android,out-of-memory,Java,Android,Out Of Memory,我正在开发一个远程备份应用程序,有时我需要上传大文件,例如15MB,我在一些手机上测试过,我发现内存不足错误 使用此功能是否有减少内存使用的方法 public int uploadFile(String sourceFileUri) { String fileName = sourceFileUri; HttpURLConnection conn = null; DataOutputStream dos = null; String li
public int uploadFile(String sourceFileUri) {
String fileName = sourceFileUri;
HttpURLConnection conn = null;
DataOutputStream dos = null;
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024;
File sourceFile = new File(sourceFileUri);
if (!sourceFile.isFile()) {
runOnUiThread(new Runnable() {
public void run() {
/* messageText.setText("Source File not exist :"
+uploadFilePath + "" + uploadFileName);*/
}
});
return 0;
}
else
{
try {
// open a URL connection to the Servlet
FileInputStream fileInputStream = new FileInputStream(sourceFile);
URL url = new URL(upLoadServerUri);
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
conn.setDoInput(true); // Allow Inputs
conn.setDoOutput(true); // Allow Outputs
conn.setUseCaches(false); // Don't use a Cached Copy
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("ENCTYPE", "multipart/form-data");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
conn.setRequestProperty("uploaded_file", fileName);
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
+ fileName + "\"" + lineEnd);
dos.writeBytes(lineEnd);
// create a buffer of maximum size
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form...
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
// send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// Responses from the server (code and message)
serverResponseCode = conn.getResponseCode();
// String serverResponseMessage = conn.getResponseMessage();
// Log.i("uploadFile", "HTTP Response is : "
// + serverResponseMessage + ": " + serverResponseCode);
if(serverResponseCode == 200){
runOnUiThread(new Runnable() {
public void run() {
/*messageText.setText(msg);
Toast.makeText(UploadToServer.this, "File Upload Complete.",
Toast.LENGTH_SHORT).show();*/
}
});
}
//close the streams //
fileInputStream.close();
dos.flush();
dos.close();
} catch (MalformedURLException ex) {
// ex.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
/*messageText.setText("MalformedURLException Exception : check script url.");*/
Toast.makeText(UploadToServer.this, "MalformedURLException", Toast.LENGTH_SHORT).show();
}
});
Log.e("Upload file to server", "error: " + ex.getMessage(), ex);
} catch (Exception e) {
//e.printStackTrace();
runOnUiThread(new Runnable() {
public void run() {
//messageText.setText("Got Exception : see logcat ");
Toast.makeText(UploadToServer.this, "Got Exception : see logcat ",
Toast.LENGTH_SHORT).show();
}
});
Log.e("Upload file to server Exception", "Exception : "
+ e.getMessage(), e);
}
// dialog.dismiss();
return serverResponseCode;
} // End else block
}
这里是错误日志
java.lang.OutOfMemoryError
at java.io.ByteArrayOutputStream.expand(ByteArrayOutputStream.java:93)
at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:218)
at org.apache.harmony.luni.internal.net.www.protocol.http.HttpURLConnectionImpl$DefaultHttpOutputStream.write(HttpURLConnectionImpl.java:750)
at java.io.DataOutputStream.write(DataOutputStream.java:101)
at com.androidexample.uploadtoserver.UploadToServer.a(SourceFile:151)
at com.androidexample.uploadtoserver.e.run(SourceFile:62)
at java.lang.Thread.run(Thread.java:1102)
在修改和添加固定无缓冲区后,我得到这个错误
Exception : expected 589715 bytes but received 589840
java.io.IOException: expected 589715 bytes but received 589840
at libcore.net.http.FixedLengthOutputStream.write(FixedLengthOutputStream.java:39)
at java.io.DataOutputStream.write(DataOutputStream.java:98)
at com.androidexample.uploadtoserver.UploadToServer.uploadFile(UploadToServer.java:152)
at com.androidexample.uploadtoserver.UploadToServer$1.run(UploadToServer.java:62)
at java.lang.Thread.run(Thread.java:856)
我猜这些字节的差异是不是标题数据?如何获取标题的长度()。您应该使用HttpURLConnection的
setChunkedStreamingMode()
或setFixedLengthStreamingMode()
方法。这将防止缓冲内存中的数据并耗尽它
文件中的相关引用:
为了获得最佳性能,您应该调用
在中已知主体长度时设置FixedLengthStreamingMode(int)
advance,或设置ChunkedStreamingMode(int)(如果未设置)。否则
HttpURLConnection将被强制缓冲整个请求正文
在传输之前存储在内存中,浪费(可能会耗尽)
堆和增加延迟
更多信息:添加
conn.setFixedLengthStreamingMode(sourceFile.length());
下:
conn = (HttpURLConnection) url.openConnection();
你能帮我举个例子吗?我是java新手,实际上我在谷歌上没有找到任何例子来说明如何做到这一点,以及如何在发布数据之前知道正文长度。感谢上面提到的Avesjust like@Caner,您所要做的就是像这样调用方法:conn.setChunkedStreamingMode(maxBufferSize);您好,谢谢您的回复,但是当我设置conn.setChunkedStreamingMode(maxBufferSize)时;我的文件没有到达我的服务器。@aves:使用
setFixedLengthStreamingMode()
我们是否可以在服务器端获得完整的文件而不是分块?您好,我知道在应用程序中使用setFixedLengthStreamingMode与不使用setFixedLengthStreamingMode时使用的内存有什么区别吗?我如何在eclipse中进行测试,或者是否有其他方法来了解实际内存使用情况。谢谢使用DDMS。这里解释如下:首先启用它:从Eclipse:单击窗口>打开透视图>其他…>这种方式HttpURLConnection
将处理缓冲并以块的形式发送数据。以前,它正在缓冲整个15MB并尝试立即发送。intconn.setFixedLengthStreamingMode((int)sourceFile.length())中的convertsourceFile.length()
代码>