Develop Reference

java.net.URL retrieves unintelligible stream

I have been using a java code to retrieve an url content. The code does not work for https://www.amazon.es/. A similar python code does achieve retrieving an amazon url content.
The java code:
URL url = new URL(urlToScan);
BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream(), StandardCharsets.UTF_8));
StringBuilder builder = new StringBuilder();
for (String temp = reader.readLine(); temp != null; temp = reader.readLine())
builder.append(temp);
webpage = builder.toString();
The python code:
from urllib.request import urlopen
url = "https://www.amazon.es/"
page = urlopen(url)
html_bytes = page.read()
html = html_bytes.decode("utf-8")
print(html)
I searched amazon's html on my own looking for the used charset (in case it was a charset issue) and they are using charset="utf-8".As the html is 22,000+ lines long, I thought it could be some parsing error for long Strings. I also tried with a ByteArrayOutputStream and then instancing using String(byte[], charset) constructor.Java output:
?
Why is not java.net.URL retrieving properly the url content?

Maybe it's because of User-Agent. To set User-Agent, using URLConnection:
URL url = new URL("https://www.amazon.es/");
URLConnection connection = url.openConnection();
connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64)");
BufferedInputStream bufferedInputStream = new BufferedInputStream(connection.getInputStream());
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(bufferedInputStream));
StringBuilder buffer = new StringBuilder();
String inputLine;
while ((inputLine = bufferedReader.readLine()) != null) {
buffer.append(inputLine).append("\n");
}
bufferedReader.close();
System.out.println(buffer.toString());
While Python's urllib should be using certain User-Agent by default.

Java InputStreamReader from URL does not encode "Umlaute"

I try to read the html content from an URL. When I wan't to print the content to the console "Umlaute" like ä, ö, ü are displayed wrong.
URL url = new URL("http://www.lauftreff.de/laeufe/halbmarathon-1-2017.html");
URLConnection conn = url.openConnection();
InputStreamReader input = new InputStreamReader(conn.getInputStream(),StandardCharsets.ISO_8859_1);
BufferedReader bi = new BufferedReader(input);
String inputLine;
while((inputLine = bi.readLine()) != null){
System.out.println(inputLine);
}
In the header of the html the information of the charset says ISO_8859_1. Also UTF-8 does not work.
Has anyone an Idea what to do?

In the website the Umlaute are decoded as HTML entities. So you would need to decode those. The code below should work, but it is untested.
URL url = new URL("http://www.lauftreff.de/laeufe/halbmarathon-1-2017.html");
URLConnection conn = url.openConnection();
InputStreamReader input = new InputStreamReader(conn.getInputStream(),StandardCharsets.ISO_8859_1);
BufferedReader bi = new BufferedReader(input);
String inputLine;
while((inputLine = bi.readLine()) != null){
inputLine = StringEscapeUtils.unescapeHtml4(inputLine);
System.out.println(inputLine);
}

URLConnection didnt return complete content of file

My code looks like
URL oracle = new URL(calURL);
FileWriter overall = new FileWriter("overall.txt");
HttpURLConnection yc = (HttpURLConnection) oracle.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
overall.append("\n"+inputLine);
}
It seems it is returning only half of content .. Not getting the full content
Note : calURL is dynamically generated

calURL is taking much time to load. Before its my stream starts reading I guess. I included timeout before URL connection it is getting full data now.

Get raw text from html

Im on quite a basic level of android development.
I would like to get text from a page such as "http://www.google.com". (The page i will be using will only have text, so no pictures or something like that)
So, to be clear: I want to get the text written on a page into etc. a string in my application.
I tried this code, but im not even sure if it does what i want.
URL url = new URL(/*"http://www.google.com");
URLConnection connection = url.openConnection();
// Get the response
BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = "";
I cant get any text from it anyhow. How should I do this?

From the sample code you gave you are not even reading the response from the request. I would get the html with the following code
URL u = new URL("http://www.google.com");
URLConnection conn = u.openConnection();
BufferedReader in = new BufferedReader(
new InputStreamReader(
conn.getInputStream()));
StringBuffer buffer = new StringBuffer();
String inputLine;
while ((inputLine = in.readLine()) != null)
buffer.append(inputLine);
in.close();
System.out.println(buffer.toString());
From there you would need to pass the string into some kind of html parser if you want only the text. From what I've heard JTidy would is a good library for this however I have never used any Java html parsing libraries.

You want to extract text from HTML file? You can make use of specialized tool such as the Jericho HTML parser library. I'm not sure if it can be used directly in Android app, it is quite big, but it is open source so you can make use of its code and take only what you need for your task.

Here is one way:
public String scrape(String urlString) throws Exception {
URL url = new URL(urlString);
URLConnection connection = url.openConnection();
BufferedReader reader = new BufferedReader(new InputStreamReader(
connection.getInputStream()));
String line = null, data = "";
while ((line = reader.readLine()) != null) {
data += line + "\n";
}
return data;
}
Here is another.

Java URL hangs and never reads in Website

I am trying to read in a website and save it to a string. I'm using this code below which works perfectly fine in Eclipse. But when I try to run the program via the command line in Windows like "java MyProgram", the program starts and just hangs and never reads in the URL. Anyone know why this would be happening?
URL link = new URL("http://www.yahoo.com");
BufferedReader in = new BufferedReader(new InputStreamReader(link.openStream()));
//InputStream in = link.openStream();
String inputLine = "";
int count = 0;
while ((inputLine = in.readLine()) != null)
{
site = site + "\n" + inputLine;
}
in.close();
...

It could be because you are behind a proxy, and Eclipse is automatically adding settings in to configure this.
If you are behind a proxy, when running from the command prompt, try setting the java.net.useSystemProxies property. You can also manually configure proxy settings with a few network properties found here (http.proxyHost, http.proxyPort).

I encountered such a problem and found a solution.
Here my working code:
// Create a URL for the desired page
URL url = new URL("your url");
// Get connection
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(5000); // 5 seconds connectTimeout
connection.setReadTimeout(5000 ); // 5 seconds socketTimeout
// Connect
connection.connect(); // Without this line, method readLine() stucks!!!
// because it reads incorrect data, possibly from another memory area
InputStreamReader isr = new InputStreamReader(url.openStream(),"UTF-8");
BufferedReader in = new BufferedReader(isr);
String str;
while (true) {
str = in.readLine();
if(str==null){break;}
listItems.add(str);
}
// Closing all
in.close();
isr.close();
connection.disconnect();

If that's all your code is doing, there's no reason it shoudln't work from the command line. I suspect you've cut out what's broken. For example:
public static void main(String[] args) throws Exception {
String site = "";
URL link = new URL("http://www.yahoo.com");
BufferedReader in = new BufferedReader(new InputStreamReader(link.openStream()));
//InputStream in = link.openStream();
String inputLine = "";
int count = 0;
while ((inputLine = in.readLine()) != null) {
site = site + "\n" + inputLine;
}
in.close();
System.out.println(site);
}
works fine. Another possibility would be if you're running it in Eclipse and from the command line on two different computers, and the latter can't reach http://www.yahoo.com.