C download binary file java urlconnection
Full project attached below. Have c download binary file java urlconnection encountered below exception while running this as a standalone program? Exception in thread "main" java. Connection reset at java. New Unknown Source at sun. Base64Coder is a class inside the zip file.
Funny that Google did not know that and no one at Omniture knew that when I asked on the forums:. Should be a multiple of 4. Hi, I tried two approaches: I copied the codes above into my test project, downloaded Base64Coder class and all c download binary file java urlconnection dependencies. With both approaches, the result was the same: Server returned HTTP response code: One thing I noticed the difference is the "Nonce" value.
The above code as well as the code downloaded from the zip file, they both use date. Not sure if that is the issue but would someone be able to help out. Did you get solution to above issue you were facing "Exception in thread "main" java. Getting the same, server I downloaded the zip and used both of those files, only adding in my proxy and a System. Here's a more explained version, but it's in php. Got it working in 1. I think all the problems are related to base64 encoding.
Got lucky and figured out something about apache commons and magically it worked. Must be logged in to comment. Login now to comment! Uses the following classes. Cecilia Lam Would there be any samples code similar to this one in.
Portal Have you encountered below exception while running this as a standalone program? Sanjay Joshi while running this program from c download binary file java urlconnection IDE we are getting this exception: I googled and round this: But that is apparently not what is wanted. Funny that Google did not know that and no one at Omniture knew that when I asked on the forums: Adobe, can you guys look into this?
We need this to work in 1.
Most hosts are computers, but c download binary file java urlconnection also include routers, printers, fax machines, soda machines, bat houses, etc. This is written in dotted quad format like Numeric addresses are mapped to names like www. It is used by other network classes like Socket and ServerSocket to identify hosts. There are no public InetAddress constructors. Arbitrary addresses may not be created. Ports are logical abstractions that allow one host to communicate simultaneously with many other hosts.
The time protocol, RFCspecifies a binary representation, for the time that's legible to computers. Content and protocol handlers separate the data being downloaded from the the protocol used to download it. The protocol handler negotiates with the server and parses any headers. It gives the content handler only the actual data of the requested resource. When the virtual machine creates a URL object, it looks for a protocol handler that understands the protocol part of the URL such as "http" or "mailto".
The exact protocols that Java supports vary from implementation to implementation though http and file are supported pretty much everywhere. There are four six in 1. You can also construct the URL by passing its pieces to the constructor, like this: If the ref doesn't exist, it's just null, so watch out for NullPointerException s. Better yet, test to see that it's non-null before using it.
The openStream method connects to c download binary file java urlconnection server specified in the URL and returns an InputStream object fed by the data from that connection. Network connections are less reliable and slower than files. Sees a carriage return, waits to see if next character is c download binary file java urlconnection line feed before returning. What readLine should do: Sees a c download binary file java urlconnection return, return, throw away next character if it's a linefeed.
There are times when the server needs to get data from the client rather than the other way around. The common way to do this c download binary file java urlconnection with a form like this one:.
MIME headers contain name-value pairs, essentially a name followed by a colon and a space, followed by a value. When a web server responds to a web browser it sends a MIME header along with the response that looks something like this: Sat, 02 Aug Tue, 29 Jul URLEncoder class contains a single static method which encodes strings in x-www-form-url-encoded format. This prints the properly encoded query string: URLDecoder class contains a single static method which decodes strings in x-www-form-url-encoded format.
URLConnection class is c download binary file java urlconnection abstract class that handles communication with different kinds of servers like ftp servers and web servers. The parameters for the connection and the request properties that the client sends to the server are set up. Data may be read from the connection in one of two ways raw by using the input stream returned by getInputStream.
Data can be sent to the server using the output stream provided by getOutputStream. The getHeaderField String name method returns the string value of a named header field.
You can use this in combination with getHeaderField to loop through the complete header. Utility methods that read a named header and convert its value into an int and a long respectively. The long returned by getHeaderFieldDate can be converted into a Date object using a Date constructor like this: These return the values of six particularly common header fields: Before getting the connection's input stream, get the connection's output stream and write to it.
If you also want to read from the connection, you should set doInput to true with setDoInput true too. C download binary file java urlconnection getOutputStream returns an output stream on which you can write the x-www-form-urlencoded name-value pairs.
A typical HTTP response from a web server begins like this: After you've connected, you can retrieve the numeric response code in the above example--with the getResponseCode method and the message associated with it--OK in the above example--with the getResponseMessage method. ProtocolExceptiona subclass of IOExceptionis thrown if an unknown protocol is specified. GET is the default method. The boolean usingProxy method returns true if web connections are being funneled through a proxy server, false if they're not.
Most web servers can be configured to automatically redirect browsers to the new location of a page that's moved. To redirect browsers, a server sends a level response and a Location header that specifies the new location of the requested page.
HTML is returned for browsers that don't understand redirects, but most modern browsers jump straight to the page specified in the Location header instead. Because redirects can change the site which a user is connecting without their knowledge so redirects are not arbitrarily followed by URLConnections. Web Client Programming online course http:
A s far as a program is concerneda network is just another possible source of input data, and another place where data can be output. That does oversimplify things, because networks are not as easy to work with as files are. But in Java, you can do network communication using input streams and output streams, just as you can use such streams to communicate with the user or to work with files. Nevertheless, opening a network connection c download binary file java urlconnection two computers is a bit tricky, since there are two computers involved and they have to somehow agree to open a connection.
And when each computer can send data to the other, synchronizing communication can be a problem. One of the standard Java packages is called java. This package includes several classes that can be used for networking. One of these, which is fairly high-level, is based on the World-Wide Web, and provides the sort of network communication capability that is used by a Web browser when it downloads pages for you to view.
The main classes for this style of networking are java. A URLConnection represents a network connection to such a resource. It is based on the idea of a socket. A socket is used by a program to establish a connection with another program on a network. Communication over a network involves two sockets, c download binary file java urlconnection on each of the computers involved in the communication.
Java uses a class called java. Socket to represent sockets c download binary file java urlconnection are used for network communication. The term "socket" presumably comes from an image of physically plugging a wire into a computer to establish a connection to a network, but it is important to understand that a socket, as the term is used here, is simply an object belonging to the class Socket.
In particular, a program can have several sockets at the same time, each connecting it to another program running on some other computer on the network -- or even running on the same computer. All these connections use the same physical network connection. This section gives a brief introduction to these basic networking classes, and shows how they relate to input and output streams.
Every resource has an address, which identifies it uniquely and contains enough information for a Web browser to find the resource on the network and retrieve it. The address is called a "url" or "universal resource locator. An object belonging to the URL class represents such an address. A url is ordinarily specified as a string, such as " http: There are also relative url's. A relative url specifies the location of a resource relative to the location of another url, which is called the base or context for the relative url.
For example, if the context is given by the url http: An object of the class C download binary file java urlconnection is not simply a string, but it can be constructed from a string representation of a url. A URL object can also be constructed from another URL object, representing a context, plus a string that specifies a url relative to that context.
These constructors have prototypes. Note that these constructors will throw an exception of type MalformedURLException if the specified strings don't represent legal url's. Once you have a valid URL object, you can call its openConnection method to set up a connection.
This method returns a URLConnection. This is done by calling its getInputStream method. Once the InputStream has been created, you can read from it in the usual way, including wrapping it in another input stream type, such as BufferedReaderor using a Scanner.
Reading from the stream can, of course, generate exceptions. The return value can be null if the type of information is not yet known or if c download binary file java urlconnection is not possible to determine the type. The type might not be available until after the input stream has been created, so you should generally call getContentType after getInputStream. The string returned by getContentType is in a format called a mime type.
All mime types contain two parts: If you are only interested in text data, for example, you can check whether the string returned by getContentType starts with "text". Mime types were first introduced to describe the content of email messages.
The name stands for "Multipurpose Internet Mail Extensions. Let's look at a short example c download binary file java urlconnection uses all this to read the data c download binary file java urlconnection a URL. This subroutine opens a connection to a specified URL, checks that the type of data at the URL is text, and then copies the text c download binary file java urlconnection the screen.
Many of the operations in this subroutine can throw exceptions. They are handled by declaring that the c download binary file java urlconnection " throws IOException " and leaving it up to the main program to decide what to do when an error occurs. A complete program that uses this subroutine can be found in the file FetchURL. For this program, a URL can begin with "http: Try the program with URL math. Try it with some bad inputs to see the various errors that can occur.
In fact, there is a more basic communication protocol called UDP that can be used instead c download binary file java urlconnection TCP in certain applications. Once such a connection is made, communication takes place using input streams and output streams.
Each program has its own input stream and its own output stream. Data written by one program to its output stream is transmitted to the other computer. There, it enters the input stream of the program at the other end of the network connection. When that program reads data from its input stream, it is receiving the data that was transmitted to it over the network. The hard part, then, is making a network connection in the first place. Two sockets are involved.
To get things started, one program c download binary file java urlconnection create c download binary file java urlconnection socket that will wait passively until a connection request comes in from another socket. The waiting socket is said to be listening for a connection. On the other side of the connection-to-be, another program creates a socket that sends out a connection request to the listening socket.
When the listening socket receives the connection request, it responds, and the connection is established. Once that is done, each program can obtain an input stream and an output stream for sending data over the connection. Communication takes place through these streams until one program or the other closes the connection.
A program that creates a listening socket is sometimes said to be a serverand the socket is called a server socket. A program that connects to a server is called a clientand the socket that it uses to make a connection is called a client socket. The idea is that the server is out there somewhere on the network, waiting for a connection request c download binary file java urlconnection some client. The server can be thought of as offering some kind of service, and the client gets access to that service by connecting to the server.
In many actual applications, a server program can provide connections to several clients at the same time. When a client connects to a server's listening socket, that socket does not stop listening.
Instead, it continues listening for additional client connections at the same time that the first client c download binary file java urlconnection being serviced. To do this, it is necessary to use threads. We'll look at how it works in the next chapter. The URL class that was discussed at the beginning of this section uses a client socket behind the scenes to do any necessary network communication.
On the other side of that connection is a server program that accepts a connection request from the URL object, reads a request from that object for some particular file on the server computer, and responds by transmitting the contents of that file over the network back to the URL object. After transmitting the data, the server closes the connection. A client program has to have some way to specify which computer, among all those on the network, it wants to communicate with.
Many computers can also be referred to by domain names such as math. Traditional or IPv4 IP addresses are bit integers. They are usually written in the so-called "dotted decimal" form, such as A new version of the Internet Protocol, IPv6is currently being introduced. IPv6 addresses are bit integers and c download binary file java urlconnection usually written in hexadecimal form with some colons and maybe some extra information thrown in. In actual use, IPv6 addresses are still fairly rare.
Usually, one of these is the loopback addresswhich can be used when a program wants to communicate with another program on the same computer. The loopback address has IPv4 address In addition, there can be one or more IP addresses associated with physical network connections. Your computer probably has some utility for displaying your computer's IP addresses.
I have written a small Java program, ShowMyNetwork. When I run ShowMyNetwork on my computer, the output is:. The first thing on each line is a network interface name, which is really meaningful only to the computer's operating system.
The same line also contains the IP addresses for that interface. In this example, lo0 refers to the loopback address, which has IPv4 address The most important number here is The slashes at the start of each address are not part of the actual address. The other numbers in the c download binary file java urlconnection are IPv6 addresses. Now, a single computer might have several programs doing network communication at the same time, or one program communicating with several other computers. To allow for this possibility, a network connection actually has a port number in c download binary file java urlconnection with an IP address.
A port number is just a bit positive integer. A server does not simply listen for connections -- it listens for connections on a particular port.